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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /lib/maple_tree.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/maple_tree.c')
-rw-r--r--lib/maple_tree.c7268
1 files changed, 7268 insertions, 0 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Maple Tree implementation
+ * Copyright (c) 2018-2022 Oracle Corporation
+ * Authors: Liam R. Howlett <Liam.Howlett@oracle.com>
+ * Matthew Wilcox <willy@infradead.org>
+ */
+
+/*
+ * DOC: Interesting implementation details of the Maple Tree
+ *
+ * Each node type has a number of slots for entries and a number of slots for
+ * pivots. In the case of dense nodes, the pivots are implied by the position
+ * and are simply the slot index + the minimum of the node.
+ *
+ * In regular B-Tree terms, pivots are called keys. The term pivot is used to
+ * indicate that the tree is specifying ranges, Pivots may appear in the
+ * subtree with an entry attached to the value where as keys are unique to a
+ * specific position of a B-tree. Pivot values are inclusive of the slot with
+ * the same index.
+ *
+ *
+ * The following illustrates the layout of a range64 nodes slots and pivots.
+ *
+ *
+ * Slots -> | 0 | 1 | 2 | ... | 12 | 13 | 14 | 15 |
+ * ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬
+ * │ │ │ │ │ │ │ │ └─ Implied maximum
+ * │ │ │ │ │ │ │ └─ Pivot 14
+ * │ │ │ │ │ │ └─ Pivot 13
+ * │ │ │ │ │ └─ Pivot 12
+ * │ │ │ │ └─ Pivot 11
+ * │ │ │ └─ Pivot 2
+ * │ │ └─ Pivot 1
+ * │ └─ Pivot 0
+ * └─ Implied minimum
+ *
+ * Slot contents:
+ * Internal (non-leaf) nodes contain pointers to other nodes.
+ * Leaf nodes contain entries.
+ *
+ * The location of interest is often referred to as an offset. All offsets have
+ * a slot, but the last offset has an implied pivot from the node above (or
+ * UINT_MAX for the root node.
+ *
+ * Ranges complicate certain write activities. When modifying any of
+ * the B-tree variants, it is known that one entry will either be added or
+ * deleted. When modifying the Maple Tree, one store operation may overwrite
+ * the entire data set, or one half of the tree, or the middle half of the tree.
+ *
+ */
+
+
+#include <linux/maple_tree.h>
+#include <linux/xarray.h>
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/limits.h>
+#include <asm/barrier.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/maple_tree.h>
+
+#define MA_ROOT_PARENT 1
+
+/*
+ * Maple state flags
+ * * MA_STATE_BULK - Bulk insert mode
+ * * MA_STATE_REBALANCE - Indicate a rebalance during bulk insert
+ * * MA_STATE_PREALLOC - Preallocated nodes, WARN_ON allocation
+ */
+#define MA_STATE_BULK 1
+#define MA_STATE_REBALANCE 2
+#define MA_STATE_PREALLOC 4
+
+#define ma_parent_ptr(x) ((struct maple_pnode *)(x))
+#define mas_tree_parent(x) ((unsigned long)(x->tree) | MA_ROOT_PARENT)
+#define ma_mnode_ptr(x) ((struct maple_node *)(x))
+#define ma_enode_ptr(x) ((struct maple_enode *)(x))
+static struct kmem_cache *maple_node_cache;
+
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+static const unsigned long mt_max[] = {
+ [maple_dense] = MAPLE_NODE_SLOTS,
+ [maple_leaf_64] = ULONG_MAX,
+ [maple_range_64] = ULONG_MAX,
+ [maple_arange_64] = ULONG_MAX,
+};
+#define mt_node_max(x) mt_max[mte_node_type(x)]
+#endif
+
+static const unsigned char mt_slots[] = {
+ [maple_dense] = MAPLE_NODE_SLOTS,
+ [maple_leaf_64] = MAPLE_RANGE64_SLOTS,
+ [maple_range_64] = MAPLE_RANGE64_SLOTS,
+ [maple_arange_64] = MAPLE_ARANGE64_SLOTS,
+};
+#define mt_slot_count(x) mt_slots[mte_node_type(x)]
+
+static const unsigned char mt_pivots[] = {
+ [maple_dense] = 0,
+ [maple_leaf_64] = MAPLE_RANGE64_SLOTS - 1,
+ [maple_range_64] = MAPLE_RANGE64_SLOTS - 1,
+ [maple_arange_64] = MAPLE_ARANGE64_SLOTS - 1,
+};
+#define mt_pivot_count(x) mt_pivots[mte_node_type(x)]
+
+static const unsigned char mt_min_slots[] = {
+ [maple_dense] = MAPLE_NODE_SLOTS / 2,
+ [maple_leaf_64] = (MAPLE_RANGE64_SLOTS / 2) - 2,
+ [maple_range_64] = (MAPLE_RANGE64_SLOTS / 2) - 2,
+ [maple_arange_64] = (MAPLE_ARANGE64_SLOTS / 2) - 1,
+};
+#define mt_min_slot_count(x) mt_min_slots[mte_node_type(x)]
+
+#define MAPLE_BIG_NODE_SLOTS (MAPLE_RANGE64_SLOTS * 2 + 2)
+#define MAPLE_BIG_NODE_GAPS (MAPLE_ARANGE64_SLOTS * 2 + 1)
+
+struct maple_big_node {
+ struct maple_pnode *parent;
+ unsigned long pivot[MAPLE_BIG_NODE_SLOTS - 1];
+ union {
+ struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS];
+ struct {
+ unsigned long padding[MAPLE_BIG_NODE_GAPS];
+ unsigned long gap[MAPLE_BIG_NODE_GAPS];
+ };
+ };
+ unsigned char b_end;
+ enum maple_type type;
+};
+
+/*
+ * The maple_subtree_state is used to build a tree to replace a segment of an
+ * existing tree in a more atomic way. Any walkers of the older tree will hit a
+ * dead node and restart on updates.
+ */
+struct maple_subtree_state {
+ struct ma_state *orig_l; /* Original left side of subtree */
+ struct ma_state *orig_r; /* Original right side of subtree */
+ struct ma_state *l; /* New left side of subtree */
+ struct ma_state *m; /* New middle of subtree (rare) */
+ struct ma_state *r; /* New right side of subtree */
+ struct ma_topiary *free; /* nodes to be freed */
+ struct ma_topiary *destroy; /* Nodes to be destroyed (walked and freed) */
+ struct maple_big_node *bn;
+};
+
+#ifdef CONFIG_KASAN_STACK
+/* Prevent mas_wr_bnode() from exceeding the stack frame limit */
+#define noinline_for_kasan noinline_for_stack
+#else
+#define noinline_for_kasan inline
+#endif
+
+/* Functions */
+static inline struct maple_node *mt_alloc_one(gfp_t gfp)
+{
+ return kmem_cache_alloc(maple_node_cache, gfp);
+}
+
+static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes)
+{
+ return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes);
+}
+
+static inline void mt_free_bulk(size_t size, void __rcu **nodes)
+{
+ kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes);
+}
+
+static void mt_free_rcu(struct rcu_head *head)
+{
+ struct maple_node *node = container_of(head, struct maple_node, rcu);
+
+ kmem_cache_free(maple_node_cache, node);
+}
+
+/*
+ * ma_free_rcu() - Use rcu callback to free a maple node
+ * @node: The node to free
+ *
+ * The maple tree uses the parent pointer to indicate this node is no longer in
+ * use and will be freed.
+ */
+static void ma_free_rcu(struct maple_node *node)
+{
+ WARN_ON(node->parent != ma_parent_ptr(node));
+ call_rcu(&node->rcu, mt_free_rcu);
+}
+
+static void mas_set_height(struct ma_state *mas)
+{
+ unsigned int new_flags = mas->tree->ma_flags;
+
+ new_flags &= ~MT_FLAGS_HEIGHT_MASK;
+ MAS_BUG_ON(mas, mas->depth > MAPLE_HEIGHT_MAX);
+ new_flags |= mas->depth << MT_FLAGS_HEIGHT_OFFSET;
+ mas->tree->ma_flags = new_flags;
+}
+
+static unsigned int mas_mt_height(struct ma_state *mas)
+{
+ return mt_height(mas->tree);
+}
+
+static inline enum maple_type mte_node_type(const struct maple_enode *entry)
+{
+ return ((unsigned long)entry >> MAPLE_NODE_TYPE_SHIFT) &
+ MAPLE_NODE_TYPE_MASK;
+}
+
+static inline bool ma_is_dense(const enum maple_type type)
+{
+ return type < maple_leaf_64;
+}
+
+static inline bool ma_is_leaf(const enum maple_type type)
+{
+ return type < maple_range_64;
+}
+
+static inline bool mte_is_leaf(const struct maple_enode *entry)
+{
+ return ma_is_leaf(mte_node_type(entry));
+}
+
+/*
+ * We also reserve values with the bottom two bits set to '10' which are
+ * below 4096
+ */
+static inline bool mt_is_reserved(const void *entry)
+{
+ return ((unsigned long)entry < MAPLE_RESERVED_RANGE) &&
+ xa_is_internal(entry);
+}
+
+static inline void mas_set_err(struct ma_state *mas, long err)
+{
+ mas->node = MA_ERROR(err);
+}
+
+static inline bool mas_is_ptr(const struct ma_state *mas)
+{
+ return mas->node == MAS_ROOT;
+}
+
+static inline bool mas_is_start(const struct ma_state *mas)
+{
+ return mas->node == MAS_START;
+}
+
+bool mas_is_err(struct ma_state *mas)
+{
+ return xa_is_err(mas->node);
+}
+
+static __always_inline bool mas_is_overflow(struct ma_state *mas)
+{
+ if (unlikely(mas->node == MAS_OVERFLOW))
+ return true;
+
+ return false;
+}
+
+static __always_inline bool mas_is_underflow(struct ma_state *mas)
+{
+ if (unlikely(mas->node == MAS_UNDERFLOW))
+ return true;
+
+ return false;
+}
+
+static inline bool mas_searchable(struct ma_state *mas)
+{
+ if (mas_is_none(mas))
+ return false;
+
+ if (mas_is_ptr(mas))
+ return false;
+
+ return true;
+}
+
+static inline struct maple_node *mte_to_node(const struct maple_enode *entry)
+{
+ return (struct maple_node *)((unsigned long)entry & ~MAPLE_NODE_MASK);
+}
+
+/*
+ * mte_to_mat() - Convert a maple encoded node to a maple topiary node.
+ * @entry: The maple encoded node
+ *
+ * Return: a maple topiary pointer
+ */
+static inline struct maple_topiary *mte_to_mat(const struct maple_enode *entry)
+{
+ return (struct maple_topiary *)
+ ((unsigned long)entry & ~MAPLE_NODE_MASK);
+}
+
+/*
+ * mas_mn() - Get the maple state node.
+ * @mas: The maple state
+ *
+ * Return: the maple node (not encoded - bare pointer).
+ */
+static inline struct maple_node *mas_mn(const struct ma_state *mas)
+{
+ return mte_to_node(mas->node);
+}
+
+/*
+ * mte_set_node_dead() - Set a maple encoded node as dead.
+ * @mn: The maple encoded node.
+ */
+static inline void mte_set_node_dead(struct maple_enode *mn)
+{
+ mte_to_node(mn)->parent = ma_parent_ptr(mte_to_node(mn));
+ smp_wmb(); /* Needed for RCU */
+}
+
+/* Bit 1 indicates the root is a node */
+#define MAPLE_ROOT_NODE 0x02
+/* maple_type stored bit 3-6 */
+#define MAPLE_ENODE_TYPE_SHIFT 0x03
+/* Bit 2 means a NULL somewhere below */
+#define MAPLE_ENODE_NULL 0x04
+
+static inline struct maple_enode *mt_mk_node(const struct maple_node *node,
+ enum maple_type type)
+{
+ return (void *)((unsigned long)node |
+ (type << MAPLE_ENODE_TYPE_SHIFT) | MAPLE_ENODE_NULL);
+}
+
+static inline void *mte_mk_root(const struct maple_enode *node)
+{
+ return (void *)((unsigned long)node | MAPLE_ROOT_NODE);
+}
+
+static inline void *mte_safe_root(const struct maple_enode *node)
+{
+ return (void *)((unsigned long)node & ~MAPLE_ROOT_NODE);
+}
+
+static inline void *mte_set_full(const struct maple_enode *node)
+{
+ return (void *)((unsigned long)node & ~MAPLE_ENODE_NULL);
+}
+
+static inline void *mte_clear_full(const struct maple_enode *node)
+{
+ return (void *)((unsigned long)node | MAPLE_ENODE_NULL);
+}
+
+static inline bool mte_has_null(const struct maple_enode *node)
+{
+ return (unsigned long)node & MAPLE_ENODE_NULL;
+}
+
+static inline bool ma_is_root(struct maple_node *node)
+{
+ return ((unsigned long)node->parent & MA_ROOT_PARENT);
+}
+
+static inline bool mte_is_root(const struct maple_enode *node)
+{
+ return ma_is_root(mte_to_node(node));
+}
+
+static inline bool mas_is_root_limits(const struct ma_state *mas)
+{
+ return !mas->min && mas->max == ULONG_MAX;
+}
+
+static inline bool mt_is_alloc(struct maple_tree *mt)
+{
+ return (mt->ma_flags & MT_FLAGS_ALLOC_RANGE);
+}
+
+/*
+ * The Parent Pointer
+ * Excluding root, the parent pointer is 256B aligned like all other tree nodes.
+ * When storing a 32 or 64 bit values, the offset can fit into 5 bits. The 16
+ * bit values need an extra bit to store the offset. This extra bit comes from
+ * a reuse of the last bit in the node type. This is possible by using bit 1 to
+ * indicate if bit 2 is part of the type or the slot.
+ *
+ * Note types:
+ * 0x??1 = Root
+ * 0x?00 = 16 bit nodes
+ * 0x010 = 32 bit nodes
+ * 0x110 = 64 bit nodes
+ *
+ * Slot size and alignment
+ * 0b??1 : Root
+ * 0b?00 : 16 bit values, type in 0-1, slot in 2-7
+ * 0b010 : 32 bit values, type in 0-2, slot in 3-7
+ * 0b110 : 64 bit values, type in 0-2, slot in 3-7
+ */
+
+#define MAPLE_PARENT_ROOT 0x01
+
+#define MAPLE_PARENT_SLOT_SHIFT 0x03
+#define MAPLE_PARENT_SLOT_MASK 0xF8
+
+#define MAPLE_PARENT_16B_SLOT_SHIFT 0x02
+#define MAPLE_PARENT_16B_SLOT_MASK 0xFC
+
+#define MAPLE_PARENT_RANGE64 0x06
+#define MAPLE_PARENT_RANGE32 0x04
+#define MAPLE_PARENT_NOT_RANGE16 0x02
+
+/*
+ * mte_parent_shift() - Get the parent shift for the slot storage.
+ * @parent: The parent pointer cast as an unsigned long
+ * Return: The shift into that pointer to the star to of the slot
+ */
+static inline unsigned long mte_parent_shift(unsigned long parent)
+{
+ /* Note bit 1 == 0 means 16B */
+ if (likely(parent & MAPLE_PARENT_NOT_RANGE16))
+ return MAPLE_PARENT_SLOT_SHIFT;
+
+ return MAPLE_PARENT_16B_SLOT_SHIFT;
+}
+
+/*
+ * mte_parent_slot_mask() - Get the slot mask for the parent.
+ * @parent: The parent pointer cast as an unsigned long.
+ * Return: The slot mask for that parent.
+ */
+static inline unsigned long mte_parent_slot_mask(unsigned long parent)
+{
+ /* Note bit 1 == 0 means 16B */
+ if (likely(parent & MAPLE_PARENT_NOT_RANGE16))
+ return MAPLE_PARENT_SLOT_MASK;
+
+ return MAPLE_PARENT_16B_SLOT_MASK;
+}
+
+/*
+ * mas_parent_type() - Return the maple_type of the parent from the stored
+ * parent type.
+ * @mas: The maple state
+ * @enode: The maple_enode to extract the parent's enum
+ * Return: The node->parent maple_type
+ */
+static inline
+enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode)
+{
+ unsigned long p_type;
+
+ p_type = (unsigned long)mte_to_node(enode)->parent;
+ if (WARN_ON(p_type & MAPLE_PARENT_ROOT))
+ return 0;
+
+ p_type &= MAPLE_NODE_MASK;
+ p_type &= ~mte_parent_slot_mask(p_type);
+ switch (p_type) {
+ case MAPLE_PARENT_RANGE64: /* or MAPLE_PARENT_ARANGE64 */
+ if (mt_is_alloc(mas->tree))
+ return maple_arange_64;
+ return maple_range_64;
+ }
+
+ return 0;
+}
+
+/*
+ * mas_set_parent() - Set the parent node and encode the slot
+ * @enode: The encoded maple node.
+ * @parent: The encoded maple node that is the parent of @enode.
+ * @slot: The slot that @enode resides in @parent.
+ *
+ * Slot number is encoded in the enode->parent bit 3-6 or 2-6, depending on the
+ * parent type.
+ */
+static inline
+void mas_set_parent(struct ma_state *mas, struct maple_enode *enode,
+ const struct maple_enode *parent, unsigned char slot)
+{
+ unsigned long val = (unsigned long)parent;
+ unsigned long shift;
+ unsigned long type;
+ enum maple_type p_type = mte_node_type(parent);
+
+ MAS_BUG_ON(mas, p_type == maple_dense);
+ MAS_BUG_ON(mas, p_type == maple_leaf_64);
+
+ switch (p_type) {
+ case maple_range_64:
+ case maple_arange_64:
+ shift = MAPLE_PARENT_SLOT_SHIFT;
+ type = MAPLE_PARENT_RANGE64;
+ break;
+ default:
+ case maple_dense:
+ case maple_leaf_64:
+ shift = type = 0;
+ break;
+ }
+
+ val &= ~MAPLE_NODE_MASK; /* Clear all node metadata in parent */
+ val |= (slot << shift) | type;
+ mte_to_node(enode)->parent = ma_parent_ptr(val);
+}
+
+/*
+ * mte_parent_slot() - get the parent slot of @enode.
+ * @enode: The encoded maple node.
+ *
+ * Return: The slot in the parent node where @enode resides.
+ */
+static inline unsigned int mte_parent_slot(const struct maple_enode *enode)
+{
+ unsigned long val = (unsigned long)mte_to_node(enode)->parent;
+
+ if (val & MA_ROOT_PARENT)
+ return 0;
+
+ /*
+ * Okay to use MAPLE_PARENT_16B_SLOT_MASK as the last bit will be lost
+ * by shift if the parent shift is MAPLE_PARENT_SLOT_SHIFT
+ */
+ return (val & MAPLE_PARENT_16B_SLOT_MASK) >> mte_parent_shift(val);
+}
+
+/*
+ * mte_parent() - Get the parent of @node.
+ * @node: The encoded maple node.
+ *
+ * Return: The parent maple node.
+ */
+static inline struct maple_node *mte_parent(const struct maple_enode *enode)
+{
+ return (void *)((unsigned long)
+ (mte_to_node(enode)->parent) & ~MAPLE_NODE_MASK);
+}
+
+/*
+ * ma_dead_node() - check if the @enode is dead.
+ * @enode: The encoded maple node
+ *
+ * Return: true if dead, false otherwise.
+ */
+static inline bool ma_dead_node(const struct maple_node *node)
+{
+ struct maple_node *parent;
+
+ /* Do not reorder reads from the node prior to the parent check */
+ smp_rmb();
+ parent = (void *)((unsigned long) node->parent & ~MAPLE_NODE_MASK);
+ return (parent == node);
+}
+
+/*
+ * mte_dead_node() - check if the @enode is dead.
+ * @enode: The encoded maple node
+ *
+ * Return: true if dead, false otherwise.
+ */
+static inline bool mte_dead_node(const struct maple_enode *enode)
+{
+ struct maple_node *parent, *node;
+
+ node = mte_to_node(enode);
+ /* Do not reorder reads from the node prior to the parent check */
+ smp_rmb();
+ parent = mte_parent(enode);
+ return (parent == node);
+}
+
+/*
+ * mas_allocated() - Get the number of nodes allocated in a maple state.
+ * @mas: The maple state
+ *
+ * The ma_state alloc member is overloaded to hold a pointer to the first
+ * allocated node or to the number of requested nodes to allocate. If bit 0 is
+ * set, then the alloc contains the number of requested nodes. If there is an
+ * allocated node, then the total allocated nodes is in that node.
+ *
+ * Return: The total number of nodes allocated
+ */
+static inline unsigned long mas_allocated(const struct ma_state *mas)
+{
+ if (!mas->alloc || ((unsigned long)mas->alloc & 0x1))
+ return 0;
+
+ return mas->alloc->total;
+}
+
+/*
+ * mas_set_alloc_req() - Set the requested number of allocations.
+ * @mas: the maple state
+ * @count: the number of allocations.
+ *
+ * The requested number of allocations is either in the first allocated node,
+ * located in @mas->alloc->request_count, or directly in @mas->alloc if there is
+ * no allocated node. Set the request either in the node or do the necessary
+ * encoding to store in @mas->alloc directly.
+ */
+static inline void mas_set_alloc_req(struct ma_state *mas, unsigned long count)
+{
+ if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) {
+ if (!count)
+ mas->alloc = NULL;
+ else
+ mas->alloc = (struct maple_alloc *)(((count) << 1U) | 1U);
+ return;
+ }
+
+ mas->alloc->request_count = count;
+}
+
+/*
+ * mas_alloc_req() - get the requested number of allocations.
+ * @mas: The maple state
+ *
+ * The alloc count is either stored directly in @mas, or in
+ * @mas->alloc->request_count if there is at least one node allocated. Decode
+ * the request count if it's stored directly in @mas->alloc.
+ *
+ * Return: The allocation request count.
+ */
+static inline unsigned int mas_alloc_req(const struct ma_state *mas)
+{
+ if ((unsigned long)mas->alloc & 0x1)
+ return (unsigned long)(mas->alloc) >> 1;
+ else if (mas->alloc)
+ return mas->alloc->request_count;
+ return 0;
+}
+
+/*
+ * ma_pivots() - Get a pointer to the maple node pivots.
+ * @node - the maple node
+ * @type - the node type
+ *
+ * In the event of a dead node, this array may be %NULL
+ *
+ * Return: A pointer to the maple node pivots
+ */
+static inline unsigned long *ma_pivots(struct maple_node *node,
+ enum maple_type type)
+{
+ switch (type) {
+ case maple_arange_64:
+ return node->ma64.pivot;
+ case maple_range_64:
+ case maple_leaf_64:
+ return node->mr64.pivot;
+ case maple_dense:
+ return NULL;
+ }
+ return NULL;
+}
+
+/*
+ * ma_gaps() - Get a pointer to the maple node gaps.
+ * @node - the maple node
+ * @type - the node type
+ *
+ * Return: A pointer to the maple node gaps
+ */
+static inline unsigned long *ma_gaps(struct maple_node *node,
+ enum maple_type type)
+{
+ switch (type) {
+ case maple_arange_64:
+ return node->ma64.gap;
+ case maple_range_64:
+ case maple_leaf_64:
+ case maple_dense:
+ return NULL;
+ }
+ return NULL;
+}
+
+/*
+ * mas_pivot() - Get the pivot at @piv of the maple encoded node.
+ * @mas: The maple state.
+ * @piv: The pivot.
+ *
+ * Return: the pivot at @piv of @mn.
+ */
+static inline unsigned long mas_pivot(struct ma_state *mas, unsigned char piv)
+{
+ struct maple_node *node = mas_mn(mas);
+ enum maple_type type = mte_node_type(mas->node);
+
+ if (MAS_WARN_ON(mas, piv >= mt_pivots[type])) {
+ mas_set_err(mas, -EIO);
+ return 0;
+ }
+
+ switch (type) {
+ case maple_arange_64:
+ return node->ma64.pivot[piv];
+ case maple_range_64:
+ case maple_leaf_64:
+ return node->mr64.pivot[piv];
+ case maple_dense:
+ return 0;
+ }
+ return 0;
+}
+
+/*
+ * mas_safe_pivot() - get the pivot at @piv or mas->max.
+ * @mas: The maple state
+ * @pivots: The pointer to the maple node pivots
+ * @piv: The pivot to fetch
+ * @type: The maple node type
+ *
+ * Return: The pivot at @piv within the limit of the @pivots array, @mas->max
+ * otherwise.
+ */
+static inline unsigned long
+mas_safe_pivot(const struct ma_state *mas, unsigned long *pivots,
+ unsigned char piv, enum maple_type type)
+{
+ if (piv >= mt_pivots[type])
+ return mas->max;
+
+ return pivots[piv];
+}
+
+/*
+ * mas_safe_min() - Return the minimum for a given offset.
+ * @mas: The maple state
+ * @pivots: The pointer to the maple node pivots
+ * @offset: The offset into the pivot array
+ *
+ * Return: The minimum range value that is contained in @offset.
+ */
+static inline unsigned long
+mas_safe_min(struct ma_state *mas, unsigned long *pivots, unsigned char offset)
+{
+ if (likely(offset))
+ return pivots[offset - 1] + 1;
+
+ return mas->min;
+}
+
+/*
+ * mte_set_pivot() - Set a pivot to a value in an encoded maple node.
+ * @mn: The encoded maple node
+ * @piv: The pivot offset
+ * @val: The value of the pivot
+ */
+static inline void mte_set_pivot(struct maple_enode *mn, unsigned char piv,
+ unsigned long val)
+{
+ struct maple_node *node = mte_to_node(mn);
+ enum maple_type type = mte_node_type(mn);
+
+ BUG_ON(piv >= mt_pivots[type]);
+ switch (type) {
+ default:
+ case maple_range_64:
+ case maple_leaf_64:
+ node->mr64.pivot[piv] = val;
+ break;
+ case maple_arange_64:
+ node->ma64.pivot[piv] = val;
+ break;
+ case maple_dense:
+ break;
+ }
+
+}
+
+/*
+ * ma_slots() - Get a pointer to the maple node slots.
+ * @mn: The maple node
+ * @mt: The maple node type
+ *
+ * Return: A pointer to the maple node slots
+ */
+static inline void __rcu **ma_slots(struct maple_node *mn, enum maple_type mt)
+{
+ switch (mt) {
+ default:
+ case maple_arange_64:
+ return mn->ma64.slot;
+ case maple_range_64:
+ case maple_leaf_64:
+ return mn->mr64.slot;
+ case maple_dense:
+ return mn->slot;
+ }
+}
+
+static inline bool mt_write_locked(const struct maple_tree *mt)
+{
+ return mt_external_lock(mt) ? mt_write_lock_is_held(mt) :
+ lockdep_is_held(&mt->ma_lock);
+}
+
+static inline bool mt_locked(const struct maple_tree *mt)
+{
+ return mt_external_lock(mt) ? mt_lock_is_held(mt) :
+ lockdep_is_held(&mt->ma_lock);
+}
+
+static inline void *mt_slot(const struct maple_tree *mt,
+ void __rcu **slots, unsigned char offset)
+{
+ return rcu_dereference_check(slots[offset], mt_locked(mt));
+}
+
+static inline void *mt_slot_locked(struct maple_tree *mt, void __rcu **slots,
+ unsigned char offset)
+{
+ return rcu_dereference_protected(slots[offset], mt_write_locked(mt));
+}
+/*
+ * mas_slot_locked() - Get the slot value when holding the maple tree lock.
+ * @mas: The maple state
+ * @slots: The pointer to the slots
+ * @offset: The offset into the slots array to fetch
+ *
+ * Return: The entry stored in @slots at the @offset.
+ */
+static inline void *mas_slot_locked(struct ma_state *mas, void __rcu **slots,
+ unsigned char offset)
+{
+ return mt_slot_locked(mas->tree, slots, offset);
+}
+
+/*
+ * mas_slot() - Get the slot value when not holding the maple tree lock.
+ * @mas: The maple state
+ * @slots: The pointer to the slots
+ * @offset: The offset into the slots array to fetch
+ *
+ * Return: The entry stored in @slots at the @offset
+ */
+static inline void *mas_slot(struct ma_state *mas, void __rcu **slots,
+ unsigned char offset)
+{
+ return mt_slot(mas->tree, slots, offset);
+}
+
+/*
+ * mas_root() - Get the maple tree root.
+ * @mas: The maple state.
+ *
+ * Return: The pointer to the root of the tree
+ */
+static inline void *mas_root(struct ma_state *mas)
+{
+ return rcu_dereference_check(mas->tree->ma_root, mt_locked(mas->tree));
+}
+
+static inline void *mt_root_locked(struct maple_tree *mt)
+{
+ return rcu_dereference_protected(mt->ma_root, mt_write_locked(mt));
+}
+
+/*
+ * mas_root_locked() - Get the maple tree root when holding the maple tree lock.
+ * @mas: The maple state.
+ *
+ * Return: The pointer to the root of the tree
+ */
+static inline void *mas_root_locked(struct ma_state *mas)
+{
+ return mt_root_locked(mas->tree);
+}
+
+static inline struct maple_metadata *ma_meta(struct maple_node *mn,
+ enum maple_type mt)
+{
+ switch (mt) {
+ case maple_arange_64:
+ return &mn->ma64.meta;
+ default:
+ return &mn->mr64.meta;
+ }
+}
+
+/*
+ * ma_set_meta() - Set the metadata information of a node.
+ * @mn: The maple node
+ * @mt: The maple node type
+ * @offset: The offset of the highest sub-gap in this node.
+ * @end: The end of the data in this node.
+ */
+static inline void ma_set_meta(struct maple_node *mn, enum maple_type mt,
+ unsigned char offset, unsigned char end)
+{
+ struct maple_metadata *meta = ma_meta(mn, mt);
+
+ meta->gap = offset;
+ meta->end = end;
+}
+
+/*
+ * mt_clear_meta() - clear the metadata information of a node, if it exists
+ * @mt: The maple tree
+ * @mn: The maple node
+ * @type: The maple node type
+ * @offset: The offset of the highest sub-gap in this node.
+ * @end: The end of the data in this node.
+ */
+static inline void mt_clear_meta(struct maple_tree *mt, struct maple_node *mn,
+ enum maple_type type)
+{
+ struct maple_metadata *meta;
+ unsigned long *pivots;
+ void __rcu **slots;
+ void *next;
+
+ switch (type) {
+ case maple_range_64:
+ pivots = mn->mr64.pivot;
+ if (unlikely(pivots[MAPLE_RANGE64_SLOTS - 2])) {
+ slots = mn->mr64.slot;
+ next = mt_slot_locked(mt, slots,
+ MAPLE_RANGE64_SLOTS - 1);
+ if (unlikely((mte_to_node(next) &&
+ mte_node_type(next))))
+ return; /* no metadata, could be node */
+ }
+ fallthrough;
+ case maple_arange_64:
+ meta = ma_meta(mn, type);
+ break;
+ default:
+ return;
+ }
+
+ meta->gap = 0;
+ meta->end = 0;
+}
+
+/*
+ * ma_meta_end() - Get the data end of a node from the metadata
+ * @mn: The maple node
+ * @mt: The maple node type
+ */
+static inline unsigned char ma_meta_end(struct maple_node *mn,
+ enum maple_type mt)
+{
+ struct maple_metadata *meta = ma_meta(mn, mt);
+
+ return meta->end;
+}
+
+/*
+ * ma_meta_gap() - Get the largest gap location of a node from the metadata
+ * @mn: The maple node
+ * @mt: The maple node type
+ */
+static inline unsigned char ma_meta_gap(struct maple_node *mn,
+ enum maple_type mt)
+{
+ return mn->ma64.meta.gap;
+}
+
+/*
+ * ma_set_meta_gap() - Set the largest gap location in a nodes metadata
+ * @mn: The maple node
+ * @mn: The maple node type
+ * @offset: The location of the largest gap.
+ */
+static inline void ma_set_meta_gap(struct maple_node *mn, enum maple_type mt,
+ unsigned char offset)
+{
+
+ struct maple_metadata *meta = ma_meta(mn, mt);
+
+ meta->gap = offset;
+}
+
+/*
+ * mat_add() - Add a @dead_enode to the ma_topiary of a list of dead nodes.
+ * @mat - the ma_topiary, a linked list of dead nodes.
+ * @dead_enode - the node to be marked as dead and added to the tail of the list
+ *
+ * Add the @dead_enode to the linked list in @mat.
+ */
+static inline void mat_add(struct ma_topiary *mat,
+ struct maple_enode *dead_enode)
+{
+ mte_set_node_dead(dead_enode);
+ mte_to_mat(dead_enode)->next = NULL;
+ if (!mat->tail) {
+ mat->tail = mat->head = dead_enode;
+ return;
+ }
+
+ mte_to_mat(mat->tail)->next = dead_enode;
+ mat->tail = dead_enode;
+}
+
+static void mt_free_walk(struct rcu_head *head);
+static void mt_destroy_walk(struct maple_enode *enode, struct maple_tree *mt,
+ bool free);
+/*
+ * mas_mat_destroy() - Free all nodes and subtrees in a dead list.
+ * @mas - the maple state
+ * @mat - the ma_topiary linked list of dead nodes to free.
+ *
+ * Destroy walk a dead list.
+ */
+static void mas_mat_destroy(struct ma_state *mas, struct ma_topiary *mat)
+{
+ struct maple_enode *next;
+ struct maple_node *node;
+ bool in_rcu = mt_in_rcu(mas->tree);
+
+ while (mat->head) {
+ next = mte_to_mat(mat->head)->next;
+ node = mte_to_node(mat->head);
+ mt_destroy_walk(mat->head, mas->tree, !in_rcu);
+ if (in_rcu)
+ call_rcu(&node->rcu, mt_free_walk);
+ mat->head = next;
+ }
+}
+/*
+ * mas_descend() - Descend into the slot stored in the ma_state.
+ * @mas - the maple state.
+ *
+ * Note: Not RCU safe, only use in write side or debug code.
+ */
+static inline void mas_descend(struct ma_state *mas)
+{
+ enum maple_type type;
+ unsigned long *pivots;
+ struct maple_node *node;
+ void __rcu **slots;
+
+ node = mas_mn(mas);
+ type = mte_node_type(mas->node);
+ pivots = ma_pivots(node, type);
+ slots = ma_slots(node, type);
+
+ if (mas->offset)
+ mas->min = pivots[mas->offset - 1] + 1;
+ mas->max = mas_safe_pivot(mas, pivots, mas->offset, type);
+ mas->node = mas_slot(mas, slots, mas->offset);
+}
+
+/*
+ * mte_set_gap() - Set a maple node gap.
+ * @mn: The encoded maple node
+ * @gap: The offset of the gap to set
+ * @val: The gap value
+ */
+static inline void mte_set_gap(const struct maple_enode *mn,
+ unsigned char gap, unsigned long val)
+{
+ switch (mte_node_type(mn)) {
+ default:
+ break;
+ case maple_arange_64:
+ mte_to_node(mn)->ma64.gap[gap] = val;
+ break;
+ }
+}
+
+/*
+ * mas_ascend() - Walk up a level of the tree.
+ * @mas: The maple state
+ *
+ * Sets the @mas->max and @mas->min to the correct values when walking up. This
+ * may cause several levels of walking up to find the correct min and max.
+ * May find a dead node which will cause a premature return.
+ * Return: 1 on dead node, 0 otherwise
+ */
+static int mas_ascend(struct ma_state *mas)
+{
+ struct maple_enode *p_enode; /* parent enode. */
+ struct maple_enode *a_enode; /* ancestor enode. */
+ struct maple_node *a_node; /* ancestor node. */
+ struct maple_node *p_node; /* parent node. */
+ unsigned char a_slot;
+ enum maple_type a_type;
+ unsigned long min, max;
+ unsigned long *pivots;
+ bool set_max = false, set_min = false;
+
+ a_node = mas_mn(mas);
+ if (ma_is_root(a_node)) {
+ mas->offset = 0;
+ return 0;
+ }
+
+ p_node = mte_parent(mas->node);
+ if (unlikely(a_node == p_node))
+ return 1;
+
+ a_type = mas_parent_type(mas, mas->node);
+ mas->offset = mte_parent_slot(mas->node);
+ a_enode = mt_mk_node(p_node, a_type);
+
+ /* Check to make sure all parent information is still accurate */
+ if (p_node != mte_parent(mas->node))
+ return 1;
+
+ mas->node = a_enode;
+
+ if (mte_is_root(a_enode)) {
+ mas->max = ULONG_MAX;
+ mas->min = 0;
+ return 0;
+ }
+
+ if (!mas->min)
+ set_min = true;
+
+ if (mas->max == ULONG_MAX)
+ set_max = true;
+
+ min = 0;
+ max = ULONG_MAX;
+ do {
+ p_enode = a_enode;
+ a_type = mas_parent_type(mas, p_enode);
+ a_node = mte_parent(p_enode);
+ a_slot = mte_parent_slot(p_enode);
+ a_enode = mt_mk_node(a_node, a_type);
+ pivots = ma_pivots(a_node, a_type);
+
+ if (unlikely(ma_dead_node(a_node)))
+ return 1;
+
+ if (!set_min && a_slot) {
+ set_min = true;
+ min = pivots[a_slot - 1] + 1;
+ }
+
+ if (!set_max && a_slot < mt_pivots[a_type]) {
+ set_max = true;
+ max = pivots[a_slot];
+ }
+
+ if (unlikely(ma_dead_node(a_node)))
+ return 1;
+
+ if (unlikely(ma_is_root(a_node)))
+ break;
+
+ } while (!set_min || !set_max);
+
+ mas->max = max;
+ mas->min = min;
+ return 0;
+}
+
+/*
+ * mas_pop_node() - Get a previously allocated maple node from the maple state.
+ * @mas: The maple state
+ *
+ * Return: A pointer to a maple node.
+ */
+static inline struct maple_node *mas_pop_node(struct ma_state *mas)
+{
+ struct maple_alloc *ret, *node = mas->alloc;
+ unsigned long total = mas_allocated(mas);
+ unsigned int req = mas_alloc_req(mas);
+
+ /* nothing or a request pending. */
+ if (WARN_ON(!total))
+ return NULL;
+
+ if (total == 1) {
+ /* single allocation in this ma_state */
+ mas->alloc = NULL;
+ ret = node;
+ goto single_node;
+ }
+
+ if (node->node_count == 1) {
+ /* Single allocation in this node. */
+ mas->alloc = node->slot[0];
+ mas->alloc->total = node->total - 1;
+ ret = node;
+ goto new_head;
+ }
+ node->total--;
+ ret = node->slot[--node->node_count];
+ node->slot[node->node_count] = NULL;
+
+single_node:
+new_head:
+ if (req) {
+ req++;
+ mas_set_alloc_req(mas, req);
+ }
+
+ memset(ret, 0, sizeof(*ret));
+ return (struct maple_node *)ret;
+}
+
+/*
+ * mas_push_node() - Push a node back on the maple state allocation.
+ * @mas: The maple state
+ * @used: The used maple node
+ *
+ * Stores the maple node back into @mas->alloc for reuse. Updates allocated and
+ * requested node count as necessary.
+ */
+static inline void mas_push_node(struct ma_state *mas, struct maple_node *used)
+{
+ struct maple_alloc *reuse = (struct maple_alloc *)used;
+ struct maple_alloc *head = mas->alloc;
+ unsigned long count;
+ unsigned int requested = mas_alloc_req(mas);
+
+ count = mas_allocated(mas);
+
+ reuse->request_count = 0;
+ reuse->node_count = 0;
+ if (count && (head->node_count < MAPLE_ALLOC_SLOTS)) {
+ head->slot[head->node_count++] = reuse;
+ head->total++;
+ goto done;
+ }
+
+ reuse->total = 1;
+ if ((head) && !((unsigned long)head & 0x1)) {
+ reuse->slot[0] = head;
+ reuse->node_count = 1;
+ reuse->total += head->total;
+ }
+
+ mas->alloc = reuse;
+done:
+ if (requested > 1)
+ mas_set_alloc_req(mas, requested - 1);
+}
+
+/*
+ * mas_alloc_nodes() - Allocate nodes into a maple state
+ * @mas: The maple state
+ * @gfp: The GFP Flags
+ */
+static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
+{
+ struct maple_alloc *node;
+ unsigned long allocated = mas_allocated(mas);
+ unsigned int requested = mas_alloc_req(mas);
+ unsigned int count;
+ void **slots = NULL;
+ unsigned int max_req = 0;
+
+ if (!requested)
+ return;
+
+ mas_set_alloc_req(mas, 0);
+ if (mas->mas_flags & MA_STATE_PREALLOC) {
+ if (allocated)
+ return;
+ WARN_ON(!allocated);
+ }
+
+ if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS) {
+ node = (struct maple_alloc *)mt_alloc_one(gfp);
+ if (!node)
+ goto nomem_one;
+
+ if (allocated) {
+ node->slot[0] = mas->alloc;
+ node->node_count = 1;
+ } else {
+ node->node_count = 0;
+ }
+
+ mas->alloc = node;
+ node->total = ++allocated;
+ requested--;
+ }
+
+ node = mas->alloc;
+ node->request_count = 0;
+ while (requested) {
+ max_req = MAPLE_ALLOC_SLOTS - node->node_count;
+ slots = (void **)&node->slot[node->node_count];
+ max_req = min(requested, max_req);
+ count = mt_alloc_bulk(gfp, max_req, slots);
+ if (!count)
+ goto nomem_bulk;
+
+ if (node->node_count == 0) {
+ node->slot[0]->node_count = 0;
+ node->slot[0]->request_count = 0;
+ }
+
+ node->node_count += count;
+ allocated += count;
+ node = node->slot[0];
+ requested -= count;
+ }
+ mas->alloc->total = allocated;
+ return;
+
+nomem_bulk:
+ /* Clean up potential freed allocations on bulk failure */
+ memset(slots, 0, max_req * sizeof(unsigned long));
+nomem_one:
+ mas_set_alloc_req(mas, requested);
+ if (mas->alloc && !(((unsigned long)mas->alloc & 0x1)))
+ mas->alloc->total = allocated;
+ mas_set_err(mas, -ENOMEM);
+}
+
+/*
+ * mas_free() - Free an encoded maple node
+ * @mas: The maple state
+ * @used: The encoded maple node to free.
+ *
+ * Uses rcu free if necessary, pushes @used back on the maple state allocations
+ * otherwise.
+ */
+static inline void mas_free(struct ma_state *mas, struct maple_enode *used)
+{
+ struct maple_node *tmp = mte_to_node(used);
+
+ if (mt_in_rcu(mas->tree))
+ ma_free_rcu(tmp);
+ else
+ mas_push_node(mas, tmp);
+}
+
+/*
+ * mas_node_count() - Check if enough nodes are allocated and request more if
+ * there is not enough nodes.
+ * @mas: The maple state
+ * @count: The number of nodes needed
+ * @gfp: the gfp flags
+ */
+static void mas_node_count_gfp(struct ma_state *mas, int count, gfp_t gfp)
+{
+ unsigned long allocated = mas_allocated(mas);
+
+ if (allocated < count) {
+ mas_set_alloc_req(mas, count - allocated);
+ mas_alloc_nodes(mas, gfp);
+ }
+}
+
+/*
+ * mas_node_count() - Check if enough nodes are allocated and request more if
+ * there is not enough nodes.
+ * @mas: The maple state
+ * @count: The number of nodes needed
+ *
+ * Note: Uses GFP_NOWAIT | __GFP_NOWARN for gfp flags.
+ */
+static void mas_node_count(struct ma_state *mas, int count)
+{
+ return mas_node_count_gfp(mas, count, GFP_NOWAIT | __GFP_NOWARN);
+}
+
+/*
+ * mas_start() - Sets up maple state for operations.
+ * @mas: The maple state.
+ *
+ * If mas->node == MAS_START, then set the min, max and depth to
+ * defaults.
+ *
+ * Return:
+ * - If mas->node is an error or not MAS_START, return NULL.
+ * - If it's an empty tree: NULL & mas->node == MAS_NONE
+ * - If it's a single entry: The entry & mas->node == MAS_ROOT
+ * - If it's a tree: NULL & mas->node == safe root node.
+ */
+static inline struct maple_enode *mas_start(struct ma_state *mas)
+{
+ if (likely(mas_is_start(mas))) {
+ struct maple_enode *root;
+
+ mas->min = 0;
+ mas->max = ULONG_MAX;
+
+retry:
+ mas->depth = 0;
+ root = mas_root(mas);
+ /* Tree with nodes */
+ if (likely(xa_is_node(root))) {
+ mas->depth = 1;
+ mas->node = mte_safe_root(root);
+ mas->offset = 0;
+ if (mte_dead_node(mas->node))
+ goto retry;
+
+ return NULL;
+ }
+
+ /* empty tree */
+ if (unlikely(!root)) {
+ mas->node = MAS_NONE;
+ mas->offset = MAPLE_NODE_SLOTS;
+ return NULL;
+ }
+
+ /* Single entry tree */
+ mas->node = MAS_ROOT;
+ mas->offset = MAPLE_NODE_SLOTS;
+
+ /* Single entry tree. */
+ if (mas->index > 0)
+ return NULL;
+
+ return root;
+ }
+
+ return NULL;
+}
+
+/*
+ * ma_data_end() - Find the end of the data in a node.
+ * @node: The maple node
+ * @type: The maple node type
+ * @pivots: The array of pivots in the node
+ * @max: The maximum value in the node
+ *
+ * Uses metadata to find the end of the data when possible.
+ * Return: The zero indexed last slot with data (may be null).
+ */
+static inline unsigned char ma_data_end(struct maple_node *node,
+ enum maple_type type,
+ unsigned long *pivots,
+ unsigned long max)
+{
+ unsigned char offset;
+
+ if (!pivots)
+ return 0;
+
+ if (type == maple_arange_64)
+ return ma_meta_end(node, type);
+
+ offset = mt_pivots[type] - 1;
+ if (likely(!pivots[offset]))
+ return ma_meta_end(node, type);
+
+ if (likely(pivots[offset] == max))
+ return offset;
+
+ return mt_pivots[type];
+}
+
+/*
+ * mas_data_end() - Find the end of the data (slot).
+ * @mas: the maple state
+ *
+ * This method is optimized to check the metadata of a node if the node type
+ * supports data end metadata.
+ *
+ * Return: The zero indexed last slot with data (may be null).
+ */
+static inline unsigned char mas_data_end(struct ma_state *mas)
+{
+ enum maple_type type;
+ struct maple_node *node;
+ unsigned char offset;
+ unsigned long *pivots;
+
+ type = mte_node_type(mas->node);
+ node = mas_mn(mas);
+ if (type == maple_arange_64)
+ return ma_meta_end(node, type);
+
+ pivots = ma_pivots(node, type);
+ if (unlikely(ma_dead_node(node)))
+ return 0;
+
+ offset = mt_pivots[type] - 1;
+ if (likely(!pivots[offset]))
+ return ma_meta_end(node, type);
+
+ if (likely(pivots[offset] == mas->max))
+ return offset;
+
+ return mt_pivots[type];
+}
+
+/*
+ * mas_leaf_max_gap() - Returns the largest gap in a leaf node
+ * @mas - the maple state
+ *
+ * Return: The maximum gap in the leaf.
+ */
+static unsigned long mas_leaf_max_gap(struct ma_state *mas)
+{
+ enum maple_type mt;
+ unsigned long pstart, gap, max_gap;
+ struct maple_node *mn;
+ unsigned long *pivots;
+ void __rcu **slots;
+ unsigned char i;
+ unsigned char max_piv;
+
+ mt = mte_node_type(mas->node);
+ mn = mas_mn(mas);
+ slots = ma_slots(mn, mt);
+ max_gap = 0;
+ if (unlikely(ma_is_dense(mt))) {
+ gap = 0;
+ for (i = 0; i < mt_slots[mt]; i++) {
+ if (slots[i]) {
+ if (gap > max_gap)
+ max_gap = gap;
+ gap = 0;
+ } else {
+ gap++;
+ }
+ }
+ if (gap > max_gap)
+ max_gap = gap;
+ return max_gap;
+ }
+
+ /*
+ * Check the first implied pivot optimizes the loop below and slot 1 may
+ * be skipped if there is a gap in slot 0.
+ */
+ pivots = ma_pivots(mn, mt);
+ if (likely(!slots[0])) {
+ max_gap = pivots[0] - mas->min + 1;
+ i = 2;
+ } else {
+ i = 1;
+ }
+
+ /* reduce max_piv as the special case is checked before the loop */
+ max_piv = ma_data_end(mn, mt, pivots, mas->max) - 1;
+ /*
+ * Check end implied pivot which can only be a gap on the right most
+ * node.
+ */
+ if (unlikely(mas->max == ULONG_MAX) && !slots[max_piv + 1]) {
+ gap = ULONG_MAX - pivots[max_piv];
+ if (gap > max_gap)
+ max_gap = gap;
+ }
+
+ for (; i <= max_piv; i++) {
+ /* data == no gap. */
+ if (likely(slots[i]))
+ continue;
+
+ pstart = pivots[i - 1];
+ gap = pivots[i] - pstart;
+ if (gap > max_gap)
+ max_gap = gap;
+
+ /* There cannot be two gaps in a row. */
+ i++;
+ }
+ return max_gap;
+}
+
+/*
+ * ma_max_gap() - Get the maximum gap in a maple node (non-leaf)
+ * @node: The maple node
+ * @gaps: The pointer to the gaps
+ * @mt: The maple node type
+ * @*off: Pointer to store the offset location of the gap.
+ *
+ * Uses the metadata data end to scan backwards across set gaps.
+ *
+ * Return: The maximum gap value
+ */
+static inline unsigned long
+ma_max_gap(struct maple_node *node, unsigned long *gaps, enum maple_type mt,
+ unsigned char *off)
+{
+ unsigned char offset, i;
+ unsigned long max_gap = 0;
+
+ i = offset = ma_meta_end(node, mt);
+ do {
+ if (gaps[i] > max_gap) {
+ max_gap = gaps[i];
+ offset = i;
+ }
+ } while (i--);
+
+ *off = offset;
+ return max_gap;
+}
+
+/*
+ * mas_max_gap() - find the largest gap in a non-leaf node and set the slot.
+ * @mas: The maple state.
+ *
+ * Return: The gap value.
+ */
+static inline unsigned long mas_max_gap(struct ma_state *mas)
+{
+ unsigned long *gaps;
+ unsigned char offset;
+ enum maple_type mt;
+ struct maple_node *node;
+
+ mt = mte_node_type(mas->node);
+ if (ma_is_leaf(mt))
+ return mas_leaf_max_gap(mas);
+
+ node = mas_mn(mas);
+ MAS_BUG_ON(mas, mt != maple_arange_64);
+ offset = ma_meta_gap(node, mt);
+ gaps = ma_gaps(node, mt);
+ return gaps[offset];
+}
+
+/*
+ * mas_parent_gap() - Set the parent gap and any gaps above, as needed
+ * @mas: The maple state
+ * @offset: The gap offset in the parent to set
+ * @new: The new gap value.
+ *
+ * Set the parent gap then continue to set the gap upwards, using the metadata
+ * of the parent to see if it is necessary to check the node above.
+ */
+static inline void mas_parent_gap(struct ma_state *mas, unsigned char offset,
+ unsigned long new)
+{
+ unsigned long meta_gap = 0;
+ struct maple_node *pnode;
+ struct maple_enode *penode;
+ unsigned long *pgaps;
+ unsigned char meta_offset;
+ enum maple_type pmt;
+
+ pnode = mte_parent(mas->node);
+ pmt = mas_parent_type(mas, mas->node);
+ penode = mt_mk_node(pnode, pmt);
+ pgaps = ma_gaps(pnode, pmt);
+
+ascend:
+ MAS_BUG_ON(mas, pmt != maple_arange_64);
+ meta_offset = ma_meta_gap(pnode, pmt);
+ meta_gap = pgaps[meta_offset];
+
+ pgaps[offset] = new;
+
+ if (meta_gap == new)
+ return;
+
+ if (offset != meta_offset) {
+ if (meta_gap > new)
+ return;
+
+ ma_set_meta_gap(pnode, pmt, offset);
+ } else if (new < meta_gap) {
+ new = ma_max_gap(pnode, pgaps, pmt, &meta_offset);
+ ma_set_meta_gap(pnode, pmt, meta_offset);
+ }
+
+ if (ma_is_root(pnode))
+ return;
+
+ /* Go to the parent node. */
+ pnode = mte_parent(penode);
+ pmt = mas_parent_type(mas, penode);
+ pgaps = ma_gaps(pnode, pmt);
+ offset = mte_parent_slot(penode);
+ penode = mt_mk_node(pnode, pmt);
+ goto ascend;
+}
+
+/*
+ * mas_update_gap() - Update a nodes gaps and propagate up if necessary.
+ * @mas - the maple state.
+ */
+static inline void mas_update_gap(struct ma_state *mas)
+{
+ unsigned char pslot;
+ unsigned long p_gap;
+ unsigned long max_gap;
+
+ if (!mt_is_alloc(mas->tree))
+ return;
+
+ if (mte_is_root(mas->node))
+ return;
+
+ max_gap = mas_max_gap(mas);
+
+ pslot = mte_parent_slot(mas->node);
+ p_gap = ma_gaps(mte_parent(mas->node),
+ mas_parent_type(mas, mas->node))[pslot];
+
+ if (p_gap != max_gap)
+ mas_parent_gap(mas, pslot, max_gap);
+}
+
+/*
+ * mas_adopt_children() - Set the parent pointer of all nodes in @parent to
+ * @parent with the slot encoded.
+ * @mas - the maple state (for the tree)
+ * @parent - the maple encoded node containing the children.
+ */
+static inline void mas_adopt_children(struct ma_state *mas,
+ struct maple_enode *parent)
+{
+ enum maple_type type = mte_node_type(parent);
+ struct maple_node *node = mte_to_node(parent);
+ void __rcu **slots = ma_slots(node, type);
+ unsigned long *pivots = ma_pivots(node, type);
+ struct maple_enode *child;
+ unsigned char offset;
+
+ offset = ma_data_end(node, type, pivots, mas->max);
+ do {
+ child = mas_slot_locked(mas, slots, offset);
+ mas_set_parent(mas, child, parent, offset);
+ } while (offset--);
+}
+
+/*
+ * mas_put_in_tree() - Put a new node in the tree, smp_wmb(), and mark the old
+ * node as dead.
+ * @mas - the maple state with the new node
+ * @old_enode - The old maple encoded node to replace.
+ */
+static inline void mas_put_in_tree(struct ma_state *mas,
+ struct maple_enode *old_enode)
+ __must_hold(mas->tree->ma_lock)
+{
+ unsigned char offset;
+ void __rcu **slots;
+
+ if (mte_is_root(mas->node)) {
+ mas_mn(mas)->parent = ma_parent_ptr(mas_tree_parent(mas));
+ rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
+ mas_set_height(mas);
+ } else {
+
+ offset = mte_parent_slot(mas->node);
+ slots = ma_slots(mte_parent(mas->node),
+ mas_parent_type(mas, mas->node));
+ rcu_assign_pointer(slots[offset], mas->node);
+ }
+
+ mte_set_node_dead(old_enode);
+}
+
+/*
+ * mas_replace_node() - Replace a node by putting it in the tree, marking it
+ * dead, and freeing it.
+ * the parent encoding to locate the maple node in the tree.
+ * @mas - the ma_state with @mas->node pointing to the new node.
+ * @old_enode - The old maple encoded node.
+ */
+static inline void mas_replace_node(struct ma_state *mas,
+ struct maple_enode *old_enode)
+ __must_hold(mas->tree->ma_lock)
+{
+ mas_put_in_tree(mas, old_enode);
+ mas_free(mas, old_enode);
+}
+
+/*
+ * mas_find_child() - Find a child who has the parent @mas->node.
+ * @mas: the maple state with the parent.
+ * @child: the maple state to store the child.
+ */
+static inline bool mas_find_child(struct ma_state *mas, struct ma_state *child)
+ __must_hold(mas->tree->ma_lock)
+{
+ enum maple_type mt;
+ unsigned char offset;
+ unsigned char end;
+ unsigned long *pivots;
+ struct maple_enode *entry;
+ struct maple_node *node;
+ void __rcu **slots;
+
+ mt = mte_node_type(mas->node);
+ node = mas_mn(mas);
+ slots = ma_slots(node, mt);
+ pivots = ma_pivots(node, mt);
+ end = ma_data_end(node, mt, pivots, mas->max);
+ for (offset = mas->offset; offset <= end; offset++) {
+ entry = mas_slot_locked(mas, slots, offset);
+ if (mte_parent(entry) == node) {
+ *child = *mas;
+ mas->offset = offset + 1;
+ child->offset = offset;
+ mas_descend(child);
+ child->offset = 0;
+ return true;
+ }
+ }
+ return false;
+}
+
+/*
+ * mab_shift_right() - Shift the data in mab right. Note, does not clean out the
+ * old data or set b_node->b_end.
+ * @b_node: the maple_big_node
+ * @shift: the shift count
+ */
+static inline void mab_shift_right(struct maple_big_node *b_node,
+ unsigned char shift)
+{
+ unsigned long size = b_node->b_end * sizeof(unsigned long);
+
+ memmove(b_node->pivot + shift, b_node->pivot, size);
+ memmove(b_node->slot + shift, b_node->slot, size);
+ if (b_node->type == maple_arange_64)
+ memmove(b_node->gap + shift, b_node->gap, size);
+}
+
+/*
+ * mab_middle_node() - Check if a middle node is needed (unlikely)
+ * @b_node: the maple_big_node that contains the data.
+ * @size: the amount of data in the b_node
+ * @split: the potential split location
+ * @slot_count: the size that can be stored in a single node being considered.
+ *
+ * Return: true if a middle node is required.
+ */
+static inline bool mab_middle_node(struct maple_big_node *b_node, int split,
+ unsigned char slot_count)
+{
+ unsigned char size = b_node->b_end;
+
+ if (size >= 2 * slot_count)
+ return true;
+
+ if (!b_node->slot[split] && (size >= 2 * slot_count - 1))
+ return true;
+
+ return false;
+}
+
+/*
+ * mab_no_null_split() - ensure the split doesn't fall on a NULL
+ * @b_node: the maple_big_node with the data
+ * @split: the suggested split location
+ * @slot_count: the number of slots in the node being considered.
+ *
+ * Return: the split location.
+ */
+static inline int mab_no_null_split(struct maple_big_node *b_node,
+ unsigned char split, unsigned char slot_count)
+{
+ if (!b_node->slot[split]) {
+ /*
+ * If the split is less than the max slot && the right side will
+ * still be sufficient, then increment the split on NULL.
+ */
+ if ((split < slot_count - 1) &&
+ (b_node->b_end - split) > (mt_min_slots[b_node->type]))
+ split++;
+ else
+ split--;
+ }
+ return split;
+}
+
+/*
+ * mab_calc_split() - Calculate the split location and if there needs to be two
+ * splits.
+ * @bn: The maple_big_node with the data
+ * @mid_split: The second split, if required. 0 otherwise.
+ *
+ * Return: The first split location. The middle split is set in @mid_split.
+ */
+static inline int mab_calc_split(struct ma_state *mas,
+ struct maple_big_node *bn, unsigned char *mid_split, unsigned long min)
+{
+ unsigned char b_end = bn->b_end;
+ int split = b_end / 2; /* Assume equal split. */
+ unsigned char slot_min, slot_count = mt_slots[bn->type];
+
+ /*
+ * To support gap tracking, all NULL entries are kept together and a node cannot
+ * end on a NULL entry, with the exception of the left-most leaf. The
+ * limitation means that the split of a node must be checked for this condition
+ * and be able to put more data in one direction or the other.
+ */
+ if (unlikely((mas->mas_flags & MA_STATE_BULK))) {
+ *mid_split = 0;
+ split = b_end - mt_min_slots[bn->type];
+
+ if (!ma_is_leaf(bn->type))
+ return split;
+
+ mas->mas_flags |= MA_STATE_REBALANCE;
+ if (!bn->slot[split])
+ split--;
+ return split;
+ }
+
+ /*
+ * Although extremely rare, it is possible to enter what is known as the 3-way
+ * split scenario. The 3-way split comes about by means of a store of a range
+ * that overwrites the end and beginning of two full nodes. The result is a set
+ * of entries that cannot be stored in 2 nodes. Sometimes, these two nodes can
+ * also be located in different parent nodes which are also full. This can
+ * carry upwards all the way to the root in the worst case.
+ */
+ if (unlikely(mab_middle_node(bn, split, slot_count))) {
+ split = b_end / 3;
+ *mid_split = split * 2;
+ } else {
+ slot_min = mt_min_slots[bn->type];
+
+ *mid_split = 0;
+ /*
+ * Avoid having a range less than the slot count unless it
+ * causes one node to be deficient.
+ * NOTE: mt_min_slots is 1 based, b_end and split are zero.
+ */
+ while ((split < slot_count - 1) &&
+ ((bn->pivot[split] - min) < slot_count - 1) &&
+ (b_end - split > slot_min))
+ split++;
+ }
+
+ /* Avoid ending a node on a NULL entry */
+ split = mab_no_null_split(bn, split, slot_count);
+
+ if (unlikely(*mid_split))
+ *mid_split = mab_no_null_split(bn, *mid_split, slot_count);
+
+ return split;
+}
+
+/*
+ * mas_mab_cp() - Copy data from a maple state inclusively to a maple_big_node
+ * and set @b_node->b_end to the next free slot.
+ * @mas: The maple state
+ * @mas_start: The starting slot to copy
+ * @mas_end: The end slot to copy (inclusively)
+ * @b_node: The maple_big_node to place the data
+ * @mab_start: The starting location in maple_big_node to store the data.
+ */
+static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start,
+ unsigned char mas_end, struct maple_big_node *b_node,
+ unsigned char mab_start)
+{
+ enum maple_type mt;
+ struct maple_node *node;
+ void __rcu **slots;
+ unsigned long *pivots, *gaps;
+ int i = mas_start, j = mab_start;
+ unsigned char piv_end;
+
+ node = mas_mn(mas);
+ mt = mte_node_type(mas->node);
+ pivots = ma_pivots(node, mt);
+ if (!i) {
+ b_node->pivot[j] = pivots[i++];
+ if (unlikely(i > mas_end))
+ goto complete;
+ j++;
+ }
+
+ piv_end = min(mas_end, mt_pivots[mt]);
+ for (; i < piv_end; i++, j++) {
+ b_node->pivot[j] = pivots[i];
+ if (unlikely(!b_node->pivot[j]))
+ break;
+
+ if (unlikely(mas->max == b_node->pivot[j]))
+ goto complete;
+ }
+
+ if (likely(i <= mas_end))
+ b_node->pivot[j] = mas_safe_pivot(mas, pivots, i, mt);
+
+complete:
+ b_node->b_end = ++j;
+ j -= mab_start;
+ slots = ma_slots(node, mt);
+ memcpy(b_node->slot + mab_start, slots + mas_start, sizeof(void *) * j);
+ if (!ma_is_leaf(mt) && mt_is_alloc(mas->tree)) {
+ gaps = ma_gaps(node, mt);
+ memcpy(b_node->gap + mab_start, gaps + mas_start,
+ sizeof(unsigned long) * j);
+ }
+}
+
+/*
+ * mas_leaf_set_meta() - Set the metadata of a leaf if possible.
+ * @mas: The maple state
+ * @node: The maple node
+ * @pivots: pointer to the maple node pivots
+ * @mt: The maple type
+ * @end: The assumed end
+ *
+ * Note, end may be incremented within this function but not modified at the
+ * source. This is fine since the metadata is the last thing to be stored in a
+ * node during a write.
+ */
+static inline void mas_leaf_set_meta(struct ma_state *mas,
+ struct maple_node *node, unsigned long *pivots,
+ enum maple_type mt, unsigned char end)
+{
+ /* There is no room for metadata already */
+ if (mt_pivots[mt] <= end)
+ return;
+
+ if (pivots[end] && pivots[end] < mas->max)
+ end++;
+
+ if (end < mt_slots[mt] - 1)
+ ma_set_meta(node, mt, 0, end);
+}
+
+/*
+ * mab_mas_cp() - Copy data from maple_big_node to a maple encoded node.
+ * @b_node: the maple_big_node that has the data
+ * @mab_start: the start location in @b_node.
+ * @mab_end: The end location in @b_node (inclusively)
+ * @mas: The maple state with the maple encoded node.
+ */
+static inline void mab_mas_cp(struct maple_big_node *b_node,
+ unsigned char mab_start, unsigned char mab_end,
+ struct ma_state *mas, bool new_max)
+{
+ int i, j = 0;
+ enum maple_type mt = mte_node_type(mas->node);
+ struct maple_node *node = mte_to_node(mas->node);
+ void __rcu **slots = ma_slots(node, mt);
+ unsigned long *pivots = ma_pivots(node, mt);
+ unsigned long *gaps = NULL;
+ unsigned char end;
+
+ if (mab_end - mab_start > mt_pivots[mt])
+ mab_end--;
+
+ if (!pivots[mt_pivots[mt] - 1])
+ slots[mt_pivots[mt]] = NULL;
+
+ i = mab_start;
+ do {
+ pivots[j++] = b_node->pivot[i++];
+ } while (i <= mab_end && likely(b_node->pivot[i]));
+
+ memcpy(slots, b_node->slot + mab_start,
+ sizeof(void *) * (i - mab_start));
+
+ if (new_max)
+ mas->max = b_node->pivot[i - 1];
+
+ end = j - 1;
+ if (likely(!ma_is_leaf(mt) && mt_is_alloc(mas->tree))) {
+ unsigned long max_gap = 0;
+ unsigned char offset = 0;
+
+ gaps = ma_gaps(node, mt);
+ do {
+ gaps[--j] = b_node->gap[--i];
+ if (gaps[j] > max_gap) {
+ offset = j;
+ max_gap = gaps[j];
+ }
+ } while (j);
+
+ ma_set_meta(node, mt, offset, end);
+ } else {
+ mas_leaf_set_meta(mas, node, pivots, mt, end);
+ }
+}
+
+/*
+ * mas_bulk_rebalance() - Rebalance the end of a tree after a bulk insert.
+ * @mas: The maple state
+ * @end: The maple node end
+ * @mt: The maple node type
+ */
+static inline void mas_bulk_rebalance(struct ma_state *mas, unsigned char end,
+ enum maple_type mt)
+{
+ if (!(mas->mas_flags & MA_STATE_BULK))
+ return;
+
+ if (mte_is_root(mas->node))
+ return;
+
+ if (end > mt_min_slots[mt]) {
+ mas->mas_flags &= ~MA_STATE_REBALANCE;
+ return;
+ }
+}
+
+/*
+ * mas_store_b_node() - Store an @entry into the b_node while also copying the
+ * data from a maple encoded node.
+ * @wr_mas: the maple write state
+ * @b_node: the maple_big_node to fill with data
+ * @offset_end: the offset to end copying
+ *
+ * Return: The actual end of the data stored in @b_node
+ */
+static noinline_for_kasan void mas_store_b_node(struct ma_wr_state *wr_mas,
+ struct maple_big_node *b_node, unsigned char offset_end)
+{
+ unsigned char slot;
+ unsigned char b_end;
+ /* Possible underflow of piv will wrap back to 0 before use. */
+ unsigned long piv;
+ struct ma_state *mas = wr_mas->mas;
+
+ b_node->type = wr_mas->type;
+ b_end = 0;
+ slot = mas->offset;
+ if (slot) {
+ /* Copy start data up to insert. */
+ mas_mab_cp(mas, 0, slot - 1, b_node, 0);
+ b_end = b_node->b_end;
+ piv = b_node->pivot[b_end - 1];
+ } else
+ piv = mas->min - 1;
+
+ if (piv + 1 < mas->index) {
+ /* Handle range starting after old range */
+ b_node->slot[b_end] = wr_mas->content;
+ if (!wr_mas->content)
+ b_node->gap[b_end] = mas->index - 1 - piv;
+ b_node->pivot[b_end++] = mas->index - 1;
+ }
+
+ /* Store the new entry. */
+ mas->offset = b_end;
+ b_node->slot[b_end] = wr_mas->entry;
+ b_node->pivot[b_end] = mas->last;
+
+ /* Appended. */
+ if (mas->last >= mas->max)
+ goto b_end;
+
+ /* Handle new range ending before old range ends */
+ piv = mas_safe_pivot(mas, wr_mas->pivots, offset_end, wr_mas->type);
+ if (piv > mas->last) {
+ if (piv == ULONG_MAX)
+ mas_bulk_rebalance(mas, b_node->b_end, wr_mas->type);
+
+ if (offset_end != slot)
+ wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
+ offset_end);
+
+ b_node->slot[++b_end] = wr_mas->content;
+ if (!wr_mas->content)
+ b_node->gap[b_end] = piv - mas->last + 1;
+ b_node->pivot[b_end] = piv;
+ }
+
+ slot = offset_end + 1;
+ if (slot > wr_mas->node_end)
+ goto b_end;
+
+ /* Copy end data to the end of the node. */
+ mas_mab_cp(mas, slot, wr_mas->node_end + 1, b_node, ++b_end);
+ b_node->b_end--;
+ return;
+
+b_end:
+ b_node->b_end = b_end;
+}
+
+/*
+ * mas_prev_sibling() - Find the previous node with the same parent.
+ * @mas: the maple state
+ *
+ * Return: True if there is a previous sibling, false otherwise.
+ */
+static inline bool mas_prev_sibling(struct ma_state *mas)
+{
+ unsigned int p_slot = mte_parent_slot(mas->node);
+
+ if (mte_is_root(mas->node))
+ return false;
+
+ if (!p_slot)
+ return false;
+
+ mas_ascend(mas);
+ mas->offset = p_slot - 1;
+ mas_descend(mas);
+ return true;
+}
+
+/*
+ * mas_next_sibling() - Find the next node with the same parent.
+ * @mas: the maple state
+ *
+ * Return: true if there is a next sibling, false otherwise.
+ */
+static inline bool mas_next_sibling(struct ma_state *mas)
+{
+ MA_STATE(parent, mas->tree, mas->index, mas->last);
+
+ if (mte_is_root(mas->node))
+ return false;
+
+ parent = *mas;
+ mas_ascend(&parent);
+ parent.offset = mte_parent_slot(mas->node) + 1;
+ if (parent.offset > mas_data_end(&parent))
+ return false;
+
+ *mas = parent;
+ mas_descend(mas);
+ return true;
+}
+
+/*
+ * mte_node_or_node() - Return the encoded node or MAS_NONE.
+ * @enode: The encoded maple node.
+ *
+ * Shorthand to avoid setting %NULLs in the tree or maple_subtree_state.
+ *
+ * Return: @enode or MAS_NONE
+ */
+static inline struct maple_enode *mte_node_or_none(struct maple_enode *enode)
+{
+ if (enode)
+ return enode;
+
+ return ma_enode_ptr(MAS_NONE);
+}
+
+/*
+ * mas_wr_node_walk() - Find the correct offset for the index in the @mas.
+ * @wr_mas: The maple write state
+ *
+ * Uses mas_slot_locked() and does not need to worry about dead nodes.
+ */
+static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+ unsigned char count, offset;
+
+ if (unlikely(ma_is_dense(wr_mas->type))) {
+ wr_mas->r_max = wr_mas->r_min = mas->index;
+ mas->offset = mas->index = mas->min;
+ return;
+ }
+
+ wr_mas->node = mas_mn(wr_mas->mas);
+ wr_mas->pivots = ma_pivots(wr_mas->node, wr_mas->type);
+ count = wr_mas->node_end = ma_data_end(wr_mas->node, wr_mas->type,
+ wr_mas->pivots, mas->max);
+ offset = mas->offset;
+
+ while (offset < count && mas->index > wr_mas->pivots[offset])
+ offset++;
+
+ wr_mas->r_max = offset < count ? wr_mas->pivots[offset] : mas->max;
+ wr_mas->r_min = mas_safe_min(mas, wr_mas->pivots, offset);
+ wr_mas->offset_end = mas->offset = offset;
+}
+
+/*
+ * mast_rebalance_next() - Rebalance against the next node
+ * @mast: The maple subtree state
+ * @old_r: The encoded maple node to the right (next node).
+ */
+static inline void mast_rebalance_next(struct maple_subtree_state *mast)
+{
+ unsigned char b_end = mast->bn->b_end;
+
+ mas_mab_cp(mast->orig_r, 0, mt_slot_count(mast->orig_r->node),
+ mast->bn, b_end);
+ mast->orig_r->last = mast->orig_r->max;
+}
+
+/*
+ * mast_rebalance_prev() - Rebalance against the previous node
+ * @mast: The maple subtree state
+ * @old_l: The encoded maple node to the left (previous node)
+ */
+static inline void mast_rebalance_prev(struct maple_subtree_state *mast)
+{
+ unsigned char end = mas_data_end(mast->orig_l) + 1;
+ unsigned char b_end = mast->bn->b_end;
+
+ mab_shift_right(mast->bn, end);
+ mas_mab_cp(mast->orig_l, 0, end - 1, mast->bn, 0);
+ mast->l->min = mast->orig_l->min;
+ mast->orig_l->index = mast->orig_l->min;
+ mast->bn->b_end = end + b_end;
+ mast->l->offset += end;
+}
+
+/*
+ * mast_spanning_rebalance() - Rebalance nodes with nearest neighbour favouring
+ * the node to the right. Checking the nodes to the right then the left at each
+ * level upwards until root is reached.
+ * Data is copied into the @mast->bn.
+ * @mast: The maple_subtree_state.
+ */
+static inline
+bool mast_spanning_rebalance(struct maple_subtree_state *mast)
+{
+ struct ma_state r_tmp = *mast->orig_r;
+ struct ma_state l_tmp = *mast->orig_l;
+ unsigned char depth = 0;
+
+ r_tmp = *mast->orig_r;
+ l_tmp = *mast->orig_l;
+ do {
+ mas_ascend(mast->orig_r);
+ mas_ascend(mast->orig_l);
+ depth++;
+ if (mast->orig_r->offset < mas_data_end(mast->orig_r)) {
+ mast->orig_r->offset++;
+ do {
+ mas_descend(mast->orig_r);
+ mast->orig_r->offset = 0;
+ } while (--depth);
+
+ mast_rebalance_next(mast);
+ *mast->orig_l = l_tmp;
+ return true;
+ } else if (mast->orig_l->offset != 0) {
+ mast->orig_l->offset--;
+ do {
+ mas_descend(mast->orig_l);
+ mast->orig_l->offset =
+ mas_data_end(mast->orig_l);
+ } while (--depth);
+
+ mast_rebalance_prev(mast);
+ *mast->orig_r = r_tmp;
+ return true;
+ }
+ } while (!mte_is_root(mast->orig_r->node));
+
+ *mast->orig_r = r_tmp;
+ *mast->orig_l = l_tmp;
+ return false;
+}
+
+/*
+ * mast_ascend() - Ascend the original left and right maple states.
+ * @mast: the maple subtree state.
+ *
+ * Ascend the original left and right sides. Set the offsets to point to the
+ * data already in the new tree (@mast->l and @mast->r).
+ */
+static inline void mast_ascend(struct maple_subtree_state *mast)
+{
+ MA_WR_STATE(wr_mas, mast->orig_r, NULL);
+ mas_ascend(mast->orig_l);
+ mas_ascend(mast->orig_r);
+
+ mast->orig_r->offset = 0;
+ mast->orig_r->index = mast->r->max;
+ /* last should be larger than or equal to index */
+ if (mast->orig_r->last < mast->orig_r->index)
+ mast->orig_r->last = mast->orig_r->index;
+
+ wr_mas.type = mte_node_type(mast->orig_r->node);
+ mas_wr_node_walk(&wr_mas);
+ /* Set up the left side of things */
+ mast->orig_l->offset = 0;
+ mast->orig_l->index = mast->l->min;
+ wr_mas.mas = mast->orig_l;
+ wr_mas.type = mte_node_type(mast->orig_l->node);
+ mas_wr_node_walk(&wr_mas);
+
+ mast->bn->type = wr_mas.type;
+}
+
+/*
+ * mas_new_ma_node() - Create and return a new maple node. Helper function.
+ * @mas: the maple state with the allocations.
+ * @b_node: the maple_big_node with the type encoding.
+ *
+ * Use the node type from the maple_big_node to allocate a new node from the
+ * ma_state. This function exists mainly for code readability.
+ *
+ * Return: A new maple encoded node
+ */
+static inline struct maple_enode
+*mas_new_ma_node(struct ma_state *mas, struct maple_big_node *b_node)
+{
+ return mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), b_node->type);
+}
+
+/*
+ * mas_mab_to_node() - Set up right and middle nodes
+ *
+ * @mas: the maple state that contains the allocations.
+ * @b_node: the node which contains the data.
+ * @left: The pointer which will have the left node
+ * @right: The pointer which may have the right node
+ * @middle: the pointer which may have the middle node (rare)
+ * @mid_split: the split location for the middle node
+ *
+ * Return: the split of left.
+ */
+static inline unsigned char mas_mab_to_node(struct ma_state *mas,
+ struct maple_big_node *b_node, struct maple_enode **left,
+ struct maple_enode **right, struct maple_enode **middle,
+ unsigned char *mid_split, unsigned long min)
+{
+ unsigned char split = 0;
+ unsigned char slot_count = mt_slots[b_node->type];
+
+ *left = mas_new_ma_node(mas, b_node);
+ *right = NULL;
+ *middle = NULL;
+ *mid_split = 0;
+
+ if (b_node->b_end < slot_count) {
+ split = b_node->b_end;
+ } else {
+ split = mab_calc_split(mas, b_node, mid_split, min);
+ *right = mas_new_ma_node(mas, b_node);
+ }
+
+ if (*mid_split)
+ *middle = mas_new_ma_node(mas, b_node);
+
+ return split;
+
+}
+
+/*
+ * mab_set_b_end() - Add entry to b_node at b_node->b_end and increment the end
+ * pointer.
+ * @b_node - the big node to add the entry
+ * @mas - the maple state to get the pivot (mas->max)
+ * @entry - the entry to add, if NULL nothing happens.
+ */
+static inline void mab_set_b_end(struct maple_big_node *b_node,
+ struct ma_state *mas,
+ void *entry)
+{
+ if (!entry)
+ return;
+
+ b_node->slot[b_node->b_end] = entry;
+ if (mt_is_alloc(mas->tree))
+ b_node->gap[b_node->b_end] = mas_max_gap(mas);
+ b_node->pivot[b_node->b_end++] = mas->max;
+}
+
+/*
+ * mas_set_split_parent() - combine_then_separate helper function. Sets the parent
+ * of @mas->node to either @left or @right, depending on @slot and @split
+ *
+ * @mas - the maple state with the node that needs a parent
+ * @left - possible parent 1
+ * @right - possible parent 2
+ * @slot - the slot the mas->node was placed
+ * @split - the split location between @left and @right
+ */
+static inline void mas_set_split_parent(struct ma_state *mas,
+ struct maple_enode *left,
+ struct maple_enode *right,
+ unsigned char *slot, unsigned char split)
+{
+ if (mas_is_none(mas))
+ return;
+
+ if ((*slot) <= split)
+ mas_set_parent(mas, mas->node, left, *slot);
+ else if (right)
+ mas_set_parent(mas, mas->node, right, (*slot) - split - 1);
+
+ (*slot)++;
+}
+
+/*
+ * mte_mid_split_check() - Check if the next node passes the mid-split
+ * @**l: Pointer to left encoded maple node.
+ * @**m: Pointer to middle encoded maple node.
+ * @**r: Pointer to right encoded maple node.
+ * @slot: The offset
+ * @*split: The split location.
+ * @mid_split: The middle split.
+ */
+static inline void mte_mid_split_check(struct maple_enode **l,
+ struct maple_enode **r,
+ struct maple_enode *right,
+ unsigned char slot,
+ unsigned char *split,
+ unsigned char mid_split)
+{
+ if (*r == right)
+ return;
+
+ if (slot < mid_split)
+ return;
+
+ *l = *r;
+ *r = right;
+ *split = mid_split;
+}
+
+/*
+ * mast_set_split_parents() - Helper function to set three nodes parents. Slot
+ * is taken from @mast->l.
+ * @mast - the maple subtree state
+ * @left - the left node
+ * @right - the right node
+ * @split - the split location.
+ */
+static inline void mast_set_split_parents(struct maple_subtree_state *mast,
+ struct maple_enode *left,
+ struct maple_enode *middle,
+ struct maple_enode *right,
+ unsigned char split,
+ unsigned char mid_split)
+{
+ unsigned char slot;
+ struct maple_enode *l = left;
+ struct maple_enode *r = right;
+
+ if (mas_is_none(mast->l))
+ return;
+
+ if (middle)
+ r = middle;
+
+ slot = mast->l->offset;
+
+ mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
+ mas_set_split_parent(mast->l, l, r, &slot, split);
+
+ mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
+ mas_set_split_parent(mast->m, l, r, &slot, split);
+
+ mte_mid_split_check(&l, &r, right, slot, &split, mid_split);
+ mas_set_split_parent(mast->r, l, r, &slot, split);
+}
+
+/*
+ * mas_topiary_node() - Dispose of a singe node
+ * @mas: The maple state for pushing nodes
+ * @enode: The encoded maple node
+ * @in_rcu: If the tree is in rcu mode
+ *
+ * The node will either be RCU freed or pushed back on the maple state.
+ */
+static inline void mas_topiary_node(struct ma_state *mas,
+ struct maple_enode *enode, bool in_rcu)
+{
+ struct maple_node *tmp;
+
+ if (enode == MAS_NONE)
+ return;
+
+ tmp = mte_to_node(enode);
+ mte_set_node_dead(enode);
+ if (in_rcu)
+ ma_free_rcu(tmp);
+ else
+ mas_push_node(mas, tmp);
+}
+
+/*
+ * mas_topiary_replace() - Replace the data with new data, then repair the
+ * parent links within the new tree. Iterate over the dead sub-tree and collect
+ * the dead subtrees and topiary the nodes that are no longer of use.
+ *
+ * The new tree will have up to three children with the correct parent. Keep
+ * track of the new entries as they need to be followed to find the next level
+ * of new entries.
+ *
+ * The old tree will have up to three children with the old parent. Keep track
+ * of the old entries as they may have more nodes below replaced. Nodes within
+ * [index, last] are dead subtrees, others need to be freed and followed.
+ *
+ * @mas: The maple state pointing at the new data
+ * @old_enode: The maple encoded node being replaced
+ *
+ */
+static inline void mas_topiary_replace(struct ma_state *mas,
+ struct maple_enode *old_enode)
+{
+ struct ma_state tmp[3], tmp_next[3];
+ MA_TOPIARY(subtrees, mas->tree);
+ bool in_rcu;
+ int i, n;
+
+ /* Place data in tree & then mark node as old */
+ mas_put_in_tree(mas, old_enode);
+
+ /* Update the parent pointers in the tree */
+ tmp[0] = *mas;
+ tmp[0].offset = 0;
+ tmp[1].node = MAS_NONE;
+ tmp[2].node = MAS_NONE;
+ while (!mte_is_leaf(tmp[0].node)) {
+ n = 0;
+ for (i = 0; i < 3; i++) {
+ if (mas_is_none(&tmp[i]))
+ continue;
+
+ while (n < 3) {
+ if (!mas_find_child(&tmp[i], &tmp_next[n]))
+ break;
+ n++;
+ }
+
+ mas_adopt_children(&tmp[i], tmp[i].node);
+ }
+
+ if (MAS_WARN_ON(mas, n == 0))
+ break;
+
+ while (n < 3)
+ tmp_next[n++].node = MAS_NONE;
+
+ for (i = 0; i < 3; i++)
+ tmp[i] = tmp_next[i];
+ }
+
+ /* Collect the old nodes that need to be discarded */
+ if (mte_is_leaf(old_enode))
+ return mas_free(mas, old_enode);
+
+ tmp[0] = *mas;
+ tmp[0].offset = 0;
+ tmp[0].node = old_enode;
+ tmp[1].node = MAS_NONE;
+ tmp[2].node = MAS_NONE;
+ in_rcu = mt_in_rcu(mas->tree);
+ do {
+ n = 0;
+ for (i = 0; i < 3; i++) {
+ if (mas_is_none(&tmp[i]))
+ continue;
+
+ while (n < 3) {
+ if (!mas_find_child(&tmp[i], &tmp_next[n]))
+ break;
+
+ if ((tmp_next[n].min >= tmp_next->index) &&
+ (tmp_next[n].max <= tmp_next->last)) {
+ mat_add(&subtrees, tmp_next[n].node);
+ tmp_next[n].node = MAS_NONE;
+ } else {
+ n++;
+ }
+ }
+ }
+
+ if (MAS_WARN_ON(mas, n == 0))
+ break;
+
+ while (n < 3)
+ tmp_next[n++].node = MAS_NONE;
+
+ for (i = 0; i < 3; i++) {
+ mas_topiary_node(mas, tmp[i].node, in_rcu);
+ tmp[i] = tmp_next[i];
+ }
+ } while (!mte_is_leaf(tmp[0].node));
+
+ for (i = 0; i < 3; i++)
+ mas_topiary_node(mas, tmp[i].node, in_rcu);
+
+ mas_mat_destroy(mas, &subtrees);
+}
+
+/*
+ * mas_wmb_replace() - Write memory barrier and replace
+ * @mas: The maple state
+ * @old: The old maple encoded node that is being replaced.
+ *
+ * Updates gap as necessary.
+ */
+static inline void mas_wmb_replace(struct ma_state *mas,
+ struct maple_enode *old_enode)
+{
+ /* Insert the new data in the tree */
+ mas_topiary_replace(mas, old_enode);
+
+ if (mte_is_leaf(mas->node))
+ return;
+
+ mas_update_gap(mas);
+}
+
+/*
+ * mast_cp_to_nodes() - Copy data out to nodes.
+ * @mast: The maple subtree state
+ * @left: The left encoded maple node
+ * @middle: The middle encoded maple node
+ * @right: The right encoded maple node
+ * @split: The location to split between left and (middle ? middle : right)
+ * @mid_split: The location to split between middle and right.
+ */
+static inline void mast_cp_to_nodes(struct maple_subtree_state *mast,
+ struct maple_enode *left, struct maple_enode *middle,
+ struct maple_enode *right, unsigned char split, unsigned char mid_split)
+{
+ bool new_lmax = true;
+
+ mast->l->node = mte_node_or_none(left);
+ mast->m->node = mte_node_or_none(middle);
+ mast->r->node = mte_node_or_none(right);
+
+ mast->l->min = mast->orig_l->min;
+ if (split == mast->bn->b_end) {
+ mast->l->max = mast->orig_r->max;
+ new_lmax = false;
+ }
+
+ mab_mas_cp(mast->bn, 0, split, mast->l, new_lmax);
+
+ if (middle) {
+ mab_mas_cp(mast->bn, 1 + split, mid_split, mast->m, true);
+ mast->m->min = mast->bn->pivot[split] + 1;
+ split = mid_split;
+ }
+
+ mast->r->max = mast->orig_r->max;
+ if (right) {
+ mab_mas_cp(mast->bn, 1 + split, mast->bn->b_end, mast->r, false);
+ mast->r->min = mast->bn->pivot[split] + 1;
+ }
+}
+
+/*
+ * mast_combine_cp_left - Copy in the original left side of the tree into the
+ * combined data set in the maple subtree state big node.
+ * @mast: The maple subtree state
+ */
+static inline void mast_combine_cp_left(struct maple_subtree_state *mast)
+{
+ unsigned char l_slot = mast->orig_l->offset;
+
+ if (!l_slot)
+ return;
+
+ mas_mab_cp(mast->orig_l, 0, l_slot - 1, mast->bn, 0);
+}
+
+/*
+ * mast_combine_cp_right: Copy in the original right side of the tree into the
+ * combined data set in the maple subtree state big node.
+ * @mast: The maple subtree state
+ */
+static inline void mast_combine_cp_right(struct maple_subtree_state *mast)
+{
+ if (mast->bn->pivot[mast->bn->b_end - 1] >= mast->orig_r->max)
+ return;
+
+ mas_mab_cp(mast->orig_r, mast->orig_r->offset + 1,
+ mt_slot_count(mast->orig_r->node), mast->bn,
+ mast->bn->b_end);
+ mast->orig_r->last = mast->orig_r->max;
+}
+
+/*
+ * mast_sufficient: Check if the maple subtree state has enough data in the big
+ * node to create at least one sufficient node
+ * @mast: the maple subtree state
+ */
+static inline bool mast_sufficient(struct maple_subtree_state *mast)
+{
+ if (mast->bn->b_end > mt_min_slot_count(mast->orig_l->node))
+ return true;
+
+ return false;
+}
+
+/*
+ * mast_overflow: Check if there is too much data in the subtree state for a
+ * single node.
+ * @mast: The maple subtree state
+ */
+static inline bool mast_overflow(struct maple_subtree_state *mast)
+{
+ if (mast->bn->b_end >= mt_slot_count(mast->orig_l->node))
+ return true;
+
+ return false;
+}
+
+static inline void *mtree_range_walk(struct ma_state *mas)
+{
+ unsigned long *pivots;
+ unsigned char offset;
+ struct maple_node *node;
+ struct maple_enode *next, *last;
+ enum maple_type type;
+ void __rcu **slots;
+ unsigned char end;
+ unsigned long max, min;
+ unsigned long prev_max, prev_min;
+
+ next = mas->node;
+ min = mas->min;
+ max = mas->max;
+ do {
+ offset = 0;
+ last = next;
+ node = mte_to_node(next);
+ type = mte_node_type(next);
+ pivots = ma_pivots(node, type);
+ end = ma_data_end(node, type, pivots, max);
+ if (unlikely(ma_dead_node(node)))
+ goto dead_node;
+
+ if (pivots[offset] >= mas->index) {
+ prev_max = max;
+ prev_min = min;
+ max = pivots[offset];
+ goto next;
+ }
+
+ do {
+ offset++;
+ } while ((offset < end) && (pivots[offset] < mas->index));
+
+ prev_min = min;
+ min = pivots[offset - 1] + 1;
+ prev_max = max;
+ if (likely(offset < end && pivots[offset]))
+ max = pivots[offset];
+
+next:
+ slots = ma_slots(node, type);
+ next = mt_slot(mas->tree, slots, offset);
+ if (unlikely(ma_dead_node(node)))
+ goto dead_node;
+ } while (!ma_is_leaf(type));
+
+ mas->offset = offset;
+ mas->index = min;
+ mas->last = max;
+ mas->min = prev_min;
+ mas->max = prev_max;
+ mas->node = last;
+ return (void *)next;
+
+dead_node:
+ mas_reset(mas);
+ return NULL;
+}
+
+/*
+ * mas_spanning_rebalance() - Rebalance across two nodes which may not be peers.
+ * @mas: The starting maple state
+ * @mast: The maple_subtree_state, keeps track of 4 maple states.
+ * @count: The estimated count of iterations needed.
+ *
+ * Follow the tree upwards from @l_mas and @r_mas for @count, or until the root
+ * is hit. First @b_node is split into two entries which are inserted into the
+ * next iteration of the loop. @b_node is returned populated with the final
+ * iteration. @mas is used to obtain allocations. orig_l_mas keeps track of the
+ * nodes that will remain active by using orig_l_mas->index and orig_l_mas->last
+ * to account of what has been copied into the new sub-tree. The update of
+ * orig_l_mas->last is used in mas_consume to find the slots that will need to
+ * be either freed or destroyed. orig_l_mas->depth keeps track of the height of
+ * the new sub-tree in case the sub-tree becomes the full tree.
+ *
+ * Return: the number of elements in b_node during the last loop.
+ */
+static int mas_spanning_rebalance(struct ma_state *mas,
+ struct maple_subtree_state *mast, unsigned char count)
+{
+ unsigned char split, mid_split;
+ unsigned char slot = 0;
+ struct maple_enode *left = NULL, *middle = NULL, *right = NULL;
+ struct maple_enode *old_enode;
+
+ MA_STATE(l_mas, mas->tree, mas->index, mas->index);
+ MA_STATE(r_mas, mas->tree, mas->index, mas->last);
+ MA_STATE(m_mas, mas->tree, mas->index, mas->index);
+
+ /*
+ * The tree needs to be rebalanced and leaves need to be kept at the same level.
+ * Rebalancing is done by use of the ``struct maple_topiary``.
+ */
+ mast->l = &l_mas;
+ mast->m = &m_mas;
+ mast->r = &r_mas;
+ l_mas.node = r_mas.node = m_mas.node = MAS_NONE;
+
+ /* Check if this is not root and has sufficient data. */
+ if (((mast->orig_l->min != 0) || (mast->orig_r->max != ULONG_MAX)) &&
+ unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type]))
+ mast_spanning_rebalance(mast);
+
+ l_mas.depth = 0;
+
+ /*
+ * Each level of the tree is examined and balanced, pushing data to the left or
+ * right, or rebalancing against left or right nodes is employed to avoid
+ * rippling up the tree to limit the amount of churn. Once a new sub-section of
+ * the tree is created, there may be a mix of new and old nodes. The old nodes
+ * will have the incorrect parent pointers and currently be in two trees: the
+ * original tree and the partially new tree. To remedy the parent pointers in
+ * the old tree, the new data is swapped into the active tree and a walk down
+ * the tree is performed and the parent pointers are updated.
+ * See mas_topiary_replace() for more information.
+ */
+ while (count--) {
+ mast->bn->b_end--;
+ mast->bn->type = mte_node_type(mast->orig_l->node);
+ split = mas_mab_to_node(mas, mast->bn, &left, &right, &middle,
+ &mid_split, mast->orig_l->min);
+ mast_set_split_parents(mast, left, middle, right, split,
+ mid_split);
+ mast_cp_to_nodes(mast, left, middle, right, split, mid_split);
+
+ /*
+ * Copy data from next level in the tree to mast->bn from next
+ * iteration
+ */
+ memset(mast->bn, 0, sizeof(struct maple_big_node));
+ mast->bn->type = mte_node_type(left);
+ l_mas.depth++;
+
+ /* Root already stored in l->node. */
+ if (mas_is_root_limits(mast->l))
+ goto new_root;
+
+ mast_ascend(mast);
+ mast_combine_cp_left(mast);
+ l_mas.offset = mast->bn->b_end;
+ mab_set_b_end(mast->bn, &l_mas, left);
+ mab_set_b_end(mast->bn, &m_mas, middle);
+ mab_set_b_end(mast->bn, &r_mas, right);
+
+ /* Copy anything necessary out of the right node. */
+ mast_combine_cp_right(mast);
+ mast->orig_l->last = mast->orig_l->max;
+
+ if (mast_sufficient(mast))
+ continue;
+
+ if (mast_overflow(mast))
+ continue;
+
+ /* May be a new root stored in mast->bn */
+ if (mas_is_root_limits(mast->orig_l))
+ break;
+
+ mast_spanning_rebalance(mast);
+
+ /* rebalancing from other nodes may require another loop. */
+ if (!count)
+ count++;
+ }
+
+ l_mas.node = mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)),
+ mte_node_type(mast->orig_l->node));
+ l_mas.depth++;
+ mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, &l_mas, true);
+ mas_set_parent(mas, left, l_mas.node, slot);
+ if (middle)
+ mas_set_parent(mas, middle, l_mas.node, ++slot);
+
+ if (right)
+ mas_set_parent(mas, right, l_mas.node, ++slot);
+
+ if (mas_is_root_limits(mast->l)) {
+new_root:
+ mas_mn(mast->l)->parent = ma_parent_ptr(mas_tree_parent(mas));
+ while (!mte_is_root(mast->orig_l->node))
+ mast_ascend(mast);
+ } else {
+ mas_mn(&l_mas)->parent = mas_mn(mast->orig_l)->parent;
+ }
+
+ old_enode = mast->orig_l->node;
+ mas->depth = l_mas.depth;
+ mas->node = l_mas.node;
+ mas->min = l_mas.min;
+ mas->max = l_mas.max;
+ mas->offset = l_mas.offset;
+ mas_wmb_replace(mas, old_enode);
+ mtree_range_walk(mas);
+ return mast->bn->b_end;
+}
+
+/*
+ * mas_rebalance() - Rebalance a given node.
+ * @mas: The maple state
+ * @b_node: The big maple node.
+ *
+ * Rebalance two nodes into a single node or two new nodes that are sufficient.
+ * Continue upwards until tree is sufficient.
+ *
+ * Return: the number of elements in b_node during the last loop.
+ */
+static inline int mas_rebalance(struct ma_state *mas,
+ struct maple_big_node *b_node)
+{
+ char empty_count = mas_mt_height(mas);
+ struct maple_subtree_state mast;
+ unsigned char shift, b_end = ++b_node->b_end;
+
+ MA_STATE(l_mas, mas->tree, mas->index, mas->last);
+ MA_STATE(r_mas, mas->tree, mas->index, mas->last);
+
+ trace_ma_op(__func__, mas);
+
+ /*
+ * Rebalancing occurs if a node is insufficient. Data is rebalanced
+ * against the node to the right if it exists, otherwise the node to the
+ * left of this node is rebalanced against this node. If rebalancing
+ * causes just one node to be produced instead of two, then the parent
+ * is also examined and rebalanced if it is insufficient. Every level
+ * tries to combine the data in the same way. If one node contains the
+ * entire range of the tree, then that node is used as a new root node.
+ */
+ mas_node_count(mas, empty_count * 2 - 1);
+ if (mas_is_err(mas))
+ return 0;
+
+ mast.orig_l = &l_mas;
+ mast.orig_r = &r_mas;
+ mast.bn = b_node;
+ mast.bn->type = mte_node_type(mas->node);
+
+ l_mas = r_mas = *mas;
+
+ if (mas_next_sibling(&r_mas)) {
+ mas_mab_cp(&r_mas, 0, mt_slot_count(r_mas.node), b_node, b_end);
+ r_mas.last = r_mas.index = r_mas.max;
+ } else {
+ mas_prev_sibling(&l_mas);
+ shift = mas_data_end(&l_mas) + 1;
+ mab_shift_right(b_node, shift);
+ mas->offset += shift;
+ mas_mab_cp(&l_mas, 0, shift - 1, b_node, 0);
+ b_node->b_end = shift + b_end;
+ l_mas.index = l_mas.last = l_mas.min;
+ }
+
+ return mas_spanning_rebalance(mas, &mast, empty_count);
+}
+
+/*
+ * mas_destroy_rebalance() - Rebalance left-most node while destroying the maple
+ * state.
+ * @mas: The maple state
+ * @end: The end of the left-most node.
+ *
+ * During a mass-insert event (such as forking), it may be necessary to
+ * rebalance the left-most node when it is not sufficient.
+ */
+static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end)
+{
+ enum maple_type mt = mte_node_type(mas->node);
+ struct maple_node reuse, *newnode, *parent, *new_left, *left, *node;
+ struct maple_enode *eparent, *old_eparent;
+ unsigned char offset, tmp, split = mt_slots[mt] / 2;
+ void __rcu **l_slots, **slots;
+ unsigned long *l_pivs, *pivs, gap;
+ bool in_rcu = mt_in_rcu(mas->tree);
+
+ MA_STATE(l_mas, mas->tree, mas->index, mas->last);
+
+ l_mas = *mas;
+ mas_prev_sibling(&l_mas);
+
+ /* set up node. */
+ if (in_rcu) {
+ /* Allocate for both left and right as well as parent. */
+ mas_node_count(mas, 3);
+ if (mas_is_err(mas))
+ return;
+
+ newnode = mas_pop_node(mas);
+ } else {
+ newnode = &reuse;
+ }
+
+ node = mas_mn(mas);
+ newnode->parent = node->parent;
+ slots = ma_slots(newnode, mt);
+ pivs = ma_pivots(newnode, mt);
+ left = mas_mn(&l_mas);
+ l_slots = ma_slots(left, mt);
+ l_pivs = ma_pivots(left, mt);
+ if (!l_slots[split])
+ split++;
+ tmp = mas_data_end(&l_mas) - split;
+
+ memcpy(slots, l_slots + split + 1, sizeof(void *) * tmp);
+ memcpy(pivs, l_pivs + split + 1, sizeof(unsigned long) * tmp);
+ pivs[tmp] = l_mas.max;
+ memcpy(slots + tmp, ma_slots(node, mt), sizeof(void *) * end);
+ memcpy(pivs + tmp, ma_pivots(node, mt), sizeof(unsigned long) * end);
+
+ l_mas.max = l_pivs[split];
+ mas->min = l_mas.max + 1;
+ old_eparent = mt_mk_node(mte_parent(l_mas.node),
+ mas_parent_type(&l_mas, l_mas.node));
+ tmp += end;
+ if (!in_rcu) {
+ unsigned char max_p = mt_pivots[mt];
+ unsigned char max_s = mt_slots[mt];
+
+ if (tmp < max_p)
+ memset(pivs + tmp, 0,
+ sizeof(unsigned long) * (max_p - tmp));
+
+ if (tmp < mt_slots[mt])
+ memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp));
+
+ memcpy(node, newnode, sizeof(struct maple_node));
+ ma_set_meta(node, mt, 0, tmp - 1);
+ mte_set_pivot(old_eparent, mte_parent_slot(l_mas.node),
+ l_pivs[split]);
+
+ /* Remove data from l_pivs. */
+ tmp = split + 1;
+ memset(l_pivs + tmp, 0, sizeof(unsigned long) * (max_p - tmp));
+ memset(l_slots + tmp, 0, sizeof(void *) * (max_s - tmp));
+ ma_set_meta(left, mt, 0, split);
+ eparent = old_eparent;
+
+ goto done;
+ }
+
+ /* RCU requires replacing both l_mas, mas, and parent. */
+ mas->node = mt_mk_node(newnode, mt);
+ ma_set_meta(newnode, mt, 0, tmp);
+
+ new_left = mas_pop_node(mas);
+ new_left->parent = left->parent;
+ mt = mte_node_type(l_mas.node);
+ slots = ma_slots(new_left, mt);
+ pivs = ma_pivots(new_left, mt);
+ memcpy(slots, l_slots, sizeof(void *) * split);
+ memcpy(pivs, l_pivs, sizeof(unsigned long) * split);
+ ma_set_meta(new_left, mt, 0, split);
+ l_mas.node = mt_mk_node(new_left, mt);
+
+ /* replace parent. */
+ offset = mte_parent_slot(mas->node);
+ mt = mas_parent_type(&l_mas, l_mas.node);
+ parent = mas_pop_node(mas);
+ slots = ma_slots(parent, mt);
+ pivs = ma_pivots(parent, mt);
+ memcpy(parent, mte_to_node(old_eparent), sizeof(struct maple_node));
+ rcu_assign_pointer(slots[offset], mas->node);
+ rcu_assign_pointer(slots[offset - 1], l_mas.node);
+ pivs[offset - 1] = l_mas.max;
+ eparent = mt_mk_node(parent, mt);
+done:
+ gap = mas_leaf_max_gap(mas);
+ mte_set_gap(eparent, mte_parent_slot(mas->node), gap);
+ gap = mas_leaf_max_gap(&l_mas);
+ mte_set_gap(eparent, mte_parent_slot(l_mas.node), gap);
+ mas_ascend(mas);
+
+ if (in_rcu) {
+ mas_replace_node(mas, old_eparent);
+ mas_adopt_children(mas, mas->node);
+ }
+
+ mas_update_gap(mas);
+}
+
+/*
+ * mas_split_final_node() - Split the final node in a subtree operation.
+ * @mast: the maple subtree state
+ * @mas: The maple state
+ * @height: The height of the tree in case it's a new root.
+ */
+static inline bool mas_split_final_node(struct maple_subtree_state *mast,
+ struct ma_state *mas, int height)
+{
+ struct maple_enode *ancestor;
+
+ if (mte_is_root(mas->node)) {
+ if (mt_is_alloc(mas->tree))
+ mast->bn->type = maple_arange_64;
+ else
+ mast->bn->type = maple_range_64;
+ mas->depth = height;
+ }
+ /*
+ * Only a single node is used here, could be root.
+ * The Big_node data should just fit in a single node.
+ */
+ ancestor = mas_new_ma_node(mas, mast->bn);
+ mas_set_parent(mas, mast->l->node, ancestor, mast->l->offset);
+ mas_set_parent(mas, mast->r->node, ancestor, mast->r->offset);
+ mte_to_node(ancestor)->parent = mas_mn(mas)->parent;
+
+ mast->l->node = ancestor;
+ mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, mast->l, true);
+ mas->offset = mast->bn->b_end - 1;
+ return true;
+}
+
+/*
+ * mast_fill_bnode() - Copy data into the big node in the subtree state
+ * @mast: The maple subtree state
+ * @mas: the maple state
+ * @skip: The number of entries to skip for new nodes insertion.
+ */
+static inline void mast_fill_bnode(struct maple_subtree_state *mast,
+ struct ma_state *mas,
+ unsigned char skip)
+{
+ bool cp = true;
+ unsigned char split;
+
+ memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap));
+ memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot));
+ memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot));
+ mast->bn->b_end = 0;
+
+ if (mte_is_root(mas->node)) {
+ cp = false;
+ } else {
+ mas_ascend(mas);
+ mas->offset = mte_parent_slot(mas->node);
+ }
+
+ if (cp && mast->l->offset)
+ mas_mab_cp(mas, 0, mast->l->offset - 1, mast->bn, 0);
+
+ split = mast->bn->b_end;
+ mab_set_b_end(mast->bn, mast->l, mast->l->node);
+ mast->r->offset = mast->bn->b_end;
+ mab_set_b_end(mast->bn, mast->r, mast->r->node);
+ if (mast->bn->pivot[mast->bn->b_end - 1] == mas->max)
+ cp = false;
+
+ if (cp)
+ mas_mab_cp(mas, split + skip, mt_slot_count(mas->node) - 1,
+ mast->bn, mast->bn->b_end);
+
+ mast->bn->b_end--;
+ mast->bn->type = mte_node_type(mas->node);
+}
+
+/*
+ * mast_split_data() - Split the data in the subtree state big node into regular
+ * nodes.
+ * @mast: The maple subtree state
+ * @mas: The maple state
+ * @split: The location to split the big node
+ */
+static inline void mast_split_data(struct maple_subtree_state *mast,
+ struct ma_state *mas, unsigned char split)
+{
+ unsigned char p_slot;
+
+ mab_mas_cp(mast->bn, 0, split, mast->l, true);
+ mte_set_pivot(mast->r->node, 0, mast->r->max);
+ mab_mas_cp(mast->bn, split + 1, mast->bn->b_end, mast->r, false);
+ mast->l->offset = mte_parent_slot(mas->node);
+ mast->l->max = mast->bn->pivot[split];
+ mast->r->min = mast->l->max + 1;
+ if (mte_is_leaf(mas->node))
+ return;
+
+ p_slot = mast->orig_l->offset;
+ mas_set_split_parent(mast->orig_l, mast->l->node, mast->r->node,
+ &p_slot, split);
+ mas_set_split_parent(mast->orig_r, mast->l->node, mast->r->node,
+ &p_slot, split);
+}
+
+/*
+ * mas_push_data() - Instead of splitting a node, it is beneficial to push the
+ * data to the right or left node if there is room.
+ * @mas: The maple state
+ * @height: The current height of the maple state
+ * @mast: The maple subtree state
+ * @left: Push left or not.
+ *
+ * Keeping the height of the tree low means faster lookups.
+ *
+ * Return: True if pushed, false otherwise.
+ */
+static inline bool mas_push_data(struct ma_state *mas, int height,
+ struct maple_subtree_state *mast, bool left)
+{
+ unsigned char slot_total = mast->bn->b_end;
+ unsigned char end, space, split;
+
+ MA_STATE(tmp_mas, mas->tree, mas->index, mas->last);
+ tmp_mas = *mas;
+ tmp_mas.depth = mast->l->depth;
+
+ if (left && !mas_prev_sibling(&tmp_mas))
+ return false;
+ else if (!left && !mas_next_sibling(&tmp_mas))
+ return false;
+
+ end = mas_data_end(&tmp_mas);
+ slot_total += end;
+ space = 2 * mt_slot_count(mas->node) - 2;
+ /* -2 instead of -1 to ensure there isn't a triple split */
+ if (ma_is_leaf(mast->bn->type))
+ space--;
+
+ if (mas->max == ULONG_MAX)
+ space--;
+
+ if (slot_total >= space)
+ return false;
+
+ /* Get the data; Fill mast->bn */
+ mast->bn->b_end++;
+ if (left) {
+ mab_shift_right(mast->bn, end + 1);
+ mas_mab_cp(&tmp_mas, 0, end, mast->bn, 0);
+ mast->bn->b_end = slot_total + 1;
+ } else {
+ mas_mab_cp(&tmp_mas, 0, end, mast->bn, mast->bn->b_end);
+ }
+
+ /* Configure mast for splitting of mast->bn */
+ split = mt_slots[mast->bn->type] - 2;
+ if (left) {
+ /* Switch mas to prev node */
+ *mas = tmp_mas;
+ /* Start using mast->l for the left side. */
+ tmp_mas.node = mast->l->node;
+ *mast->l = tmp_mas;
+ } else {
+ tmp_mas.node = mast->r->node;
+ *mast->r = tmp_mas;
+ split = slot_total - split;
+ }
+ split = mab_no_null_split(mast->bn, split, mt_slots[mast->bn->type]);
+ /* Update parent slot for split calculation. */
+ if (left)
+ mast->orig_l->offset += end + 1;
+
+ mast_split_data(mast, mas, split);
+ mast_fill_bnode(mast, mas, 2);
+ mas_split_final_node(mast, mas, height + 1);
+ return true;
+}
+
+/*
+ * mas_split() - Split data that is too big for one node into two.
+ * @mas: The maple state
+ * @b_node: The maple big node
+ * Return: 1 on success, 0 on failure.
+ */
+static int mas_split(struct ma_state *mas, struct maple_big_node *b_node)
+{
+ struct maple_subtree_state mast;
+ int height = 0;
+ unsigned char mid_split, split = 0;
+ struct maple_enode *old;
+
+ /*
+ * Splitting is handled differently from any other B-tree; the Maple
+ * Tree splits upwards. Splitting up means that the split operation
+ * occurs when the walk of the tree hits the leaves and not on the way
+ * down. The reason for splitting up is that it is impossible to know
+ * how much space will be needed until the leaf is (or leaves are)
+ * reached. Since overwriting data is allowed and a range could
+ * overwrite more than one range or result in changing one entry into 3
+ * entries, it is impossible to know if a split is required until the
+ * data is examined.
+ *
+ * Splitting is a balancing act between keeping allocations to a minimum
+ * and avoiding a 'jitter' event where a tree is expanded to make room
+ * for an entry followed by a contraction when the entry is removed. To
+ * accomplish the balance, there are empty slots remaining in both left
+ * and right nodes after a split.
+ */
+ MA_STATE(l_mas, mas->tree, mas->index, mas->last);
+ MA_STATE(r_mas, mas->tree, mas->index, mas->last);
+ MA_STATE(prev_l_mas, mas->tree, mas->index, mas->last);
+ MA_STATE(prev_r_mas, mas->tree, mas->index, mas->last);
+
+ trace_ma_op(__func__, mas);
+ mas->depth = mas_mt_height(mas);
+ /* Allocation failures will happen early. */
+ mas_node_count(mas, 1 + mas->depth * 2);
+ if (mas_is_err(mas))
+ return 0;
+
+ mast.l = &l_mas;
+ mast.r = &r_mas;
+ mast.orig_l = &prev_l_mas;
+ mast.orig_r = &prev_r_mas;
+ mast.bn = b_node;
+
+ while (height++ <= mas->depth) {
+ if (mt_slots[b_node->type] > b_node->b_end) {
+ mas_split_final_node(&mast, mas, height);
+ break;
+ }
+
+ l_mas = r_mas = *mas;
+ l_mas.node = mas_new_ma_node(mas, b_node);
+ r_mas.node = mas_new_ma_node(mas, b_node);
+ /*
+ * Another way that 'jitter' is avoided is to terminate a split up early if the
+ * left or right node has space to spare. This is referred to as "pushing left"
+ * or "pushing right" and is similar to the B* tree, except the nodes left or
+ * right can rarely be reused due to RCU, but the ripple upwards is halted which
+ * is a significant savings.
+ */
+ /* Try to push left. */
+ if (mas_push_data(mas, height, &mast, true))
+ break;
+
+ /* Try to push right. */
+ if (mas_push_data(mas, height, &mast, false))
+ break;
+
+ split = mab_calc_split(mas, b_node, &mid_split, prev_l_mas.min);
+ mast_split_data(&mast, mas, split);
+ /*
+ * Usually correct, mab_mas_cp in the above call overwrites
+ * r->max.
+ */
+ mast.r->max = mas->max;
+ mast_fill_bnode(&mast, mas, 1);
+ prev_l_mas = *mast.l;
+ prev_r_mas = *mast.r;
+ }
+
+ /* Set the original node as dead */
+ old = mas->node;
+ mas->node = l_mas.node;
+ mas_wmb_replace(mas, old);
+ mtree_range_walk(mas);
+ return 1;
+}
+
+/*
+ * mas_reuse_node() - Reuse the node to store the data.
+ * @wr_mas: The maple write state
+ * @bn: The maple big node
+ * @end: The end of the data.
+ *
+ * Will always return false in RCU mode.
+ *
+ * Return: True if node was reused, false otherwise.
+ */
+static inline bool mas_reuse_node(struct ma_wr_state *wr_mas,
+ struct maple_big_node *bn, unsigned char end)
+{
+ /* Need to be rcu safe. */
+ if (mt_in_rcu(wr_mas->mas->tree))
+ return false;
+
+ if (end > bn->b_end) {
+ int clear = mt_slots[wr_mas->type] - bn->b_end;
+
+ memset(wr_mas->slots + bn->b_end, 0, sizeof(void *) * clear--);
+ memset(wr_mas->pivots + bn->b_end, 0, sizeof(void *) * clear);
+ }
+ mab_mas_cp(bn, 0, bn->b_end, wr_mas->mas, false);
+ return true;
+}
+
+/*
+ * mas_commit_b_node() - Commit the big node into the tree.
+ * @wr_mas: The maple write state
+ * @b_node: The maple big node
+ * @end: The end of the data.
+ */
+static noinline_for_kasan int mas_commit_b_node(struct ma_wr_state *wr_mas,
+ struct maple_big_node *b_node, unsigned char end)
+{
+ struct maple_node *node;
+ struct maple_enode *old_enode;
+ unsigned char b_end = b_node->b_end;
+ enum maple_type b_type = b_node->type;
+
+ old_enode = wr_mas->mas->node;
+ if ((b_end < mt_min_slots[b_type]) &&
+ (!mte_is_root(old_enode)) &&
+ (mas_mt_height(wr_mas->mas) > 1))
+ return mas_rebalance(wr_mas->mas, b_node);
+
+ if (b_end >= mt_slots[b_type])
+ return mas_split(wr_mas->mas, b_node);
+
+ if (mas_reuse_node(wr_mas, b_node, end))
+ goto reuse_node;
+
+ mas_node_count(wr_mas->mas, 1);
+ if (mas_is_err(wr_mas->mas))
+ return 0;
+
+ node = mas_pop_node(wr_mas->mas);
+ node->parent = mas_mn(wr_mas->mas)->parent;
+ wr_mas->mas->node = mt_mk_node(node, b_type);
+ mab_mas_cp(b_node, 0, b_end, wr_mas->mas, false);
+ mas_replace_node(wr_mas->mas, old_enode);
+reuse_node:
+ mas_update_gap(wr_mas->mas);
+ return 1;
+}
+
+/*
+ * mas_root_expand() - Expand a root to a node
+ * @mas: The maple state
+ * @entry: The entry to store into the tree
+ */
+static inline int mas_root_expand(struct ma_state *mas, void *entry)
+{
+ void *contents = mas_root_locked(mas);
+ enum maple_type type = maple_leaf_64;
+ struct maple_node *node;
+ void __rcu **slots;
+ unsigned long *pivots;
+ int slot = 0;
+
+ mas_node_count(mas, 1);
+ if (unlikely(mas_is_err(mas)))
+ return 0;
+
+ node = mas_pop_node(mas);
+ pivots = ma_pivots(node, type);
+ slots = ma_slots(node, type);
+ node->parent = ma_parent_ptr(mas_tree_parent(mas));
+ mas->node = mt_mk_node(node, type);
+
+ if (mas->index) {
+ if (contents) {
+ rcu_assign_pointer(slots[slot], contents);
+ if (likely(mas->index > 1))
+ slot++;
+ }
+ pivots[slot++] = mas->index - 1;
+ }
+
+ rcu_assign_pointer(slots[slot], entry);
+ mas->offset = slot;
+ pivots[slot] = mas->last;
+ if (mas->last != ULONG_MAX)
+ pivots[++slot] = ULONG_MAX;
+
+ mas->depth = 1;
+ mas_set_height(mas);
+ ma_set_meta(node, maple_leaf_64, 0, slot);
+ /* swap the new root into the tree */
+ rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
+ return slot;
+}
+
+static inline void mas_store_root(struct ma_state *mas, void *entry)
+{
+ if (likely((mas->last != 0) || (mas->index != 0)))
+ mas_root_expand(mas, entry);
+ else if (((unsigned long) (entry) & 3) == 2)
+ mas_root_expand(mas, entry);
+ else {
+ rcu_assign_pointer(mas->tree->ma_root, entry);
+ mas->node = MAS_START;
+ }
+}
+
+/*
+ * mas_is_span_wr() - Check if the write needs to be treated as a write that
+ * spans the node.
+ * @mas: The maple state
+ * @piv: The pivot value being written
+ * @type: The maple node type
+ * @entry: The data to write
+ *
+ * Spanning writes are writes that start in one node and end in another OR if
+ * the write of a %NULL will cause the node to end with a %NULL.
+ *
+ * Return: True if this is a spanning write, false otherwise.
+ */
+static bool mas_is_span_wr(struct ma_wr_state *wr_mas)
+{
+ unsigned long max = wr_mas->r_max;
+ unsigned long last = wr_mas->mas->last;
+ enum maple_type type = wr_mas->type;
+ void *entry = wr_mas->entry;
+
+ /* Contained in this pivot, fast path */
+ if (last < max)
+ return false;
+
+ if (ma_is_leaf(type)) {
+ max = wr_mas->mas->max;
+ if (last < max)
+ return false;
+ }
+
+ if (last == max) {
+ /*
+ * The last entry of leaf node cannot be NULL unless it is the
+ * rightmost node (writing ULONG_MAX), otherwise it spans slots.
+ */
+ if (entry || last == ULONG_MAX)
+ return false;
+ }
+
+ trace_ma_write(__func__, wr_mas->mas, wr_mas->r_max, entry);
+ return true;
+}
+
+static inline void mas_wr_walk_descend(struct ma_wr_state *wr_mas)
+{
+ wr_mas->type = mte_node_type(wr_mas->mas->node);
+ mas_wr_node_walk(wr_mas);
+ wr_mas->slots = ma_slots(wr_mas->node, wr_mas->type);
+}
+
+static inline void mas_wr_walk_traverse(struct ma_wr_state *wr_mas)
+{
+ wr_mas->mas->max = wr_mas->r_max;
+ wr_mas->mas->min = wr_mas->r_min;
+ wr_mas->mas->node = wr_mas->content;
+ wr_mas->mas->offset = 0;
+ wr_mas->mas->depth++;
+}
+/*
+ * mas_wr_walk() - Walk the tree for a write.
+ * @wr_mas: The maple write state
+ *
+ * Uses mas_slot_locked() and does not need to worry about dead nodes.
+ *
+ * Return: True if it's contained in a node, false on spanning write.
+ */
+static bool mas_wr_walk(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+
+ while (true) {
+ mas_wr_walk_descend(wr_mas);
+ if (unlikely(mas_is_span_wr(wr_mas)))
+ return false;
+
+ wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
+ mas->offset);
+ if (ma_is_leaf(wr_mas->type))
+ return true;
+
+ mas_wr_walk_traverse(wr_mas);
+ }
+
+ return true;
+}
+
+static bool mas_wr_walk_index(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+
+ while (true) {
+ mas_wr_walk_descend(wr_mas);
+ wr_mas->content = mas_slot_locked(mas, wr_mas->slots,
+ mas->offset);
+ if (ma_is_leaf(wr_mas->type))
+ return true;
+ mas_wr_walk_traverse(wr_mas);
+
+ }
+ return true;
+}
+/*
+ * mas_extend_spanning_null() - Extend a store of a %NULL to include surrounding %NULLs.
+ * @l_wr_mas: The left maple write state
+ * @r_wr_mas: The right maple write state
+ */
+static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas,
+ struct ma_wr_state *r_wr_mas)
+{
+ struct ma_state *r_mas = r_wr_mas->mas;
+ struct ma_state *l_mas = l_wr_mas->mas;
+ unsigned char l_slot;
+
+ l_slot = l_mas->offset;
+ if (!l_wr_mas->content)
+ l_mas->index = l_wr_mas->r_min;
+
+ if ((l_mas->index == l_wr_mas->r_min) &&
+ (l_slot &&
+ !mas_slot_locked(l_mas, l_wr_mas->slots, l_slot - 1))) {
+ if (l_slot > 1)
+ l_mas->index = l_wr_mas->pivots[l_slot - 2] + 1;
+ else
+ l_mas->index = l_mas->min;
+
+ l_mas->offset = l_slot - 1;
+ }
+
+ if (!r_wr_mas->content) {
+ if (r_mas->last < r_wr_mas->r_max)
+ r_mas->last = r_wr_mas->r_max;
+ r_mas->offset++;
+ } else if ((r_mas->last == r_wr_mas->r_max) &&
+ (r_mas->last < r_mas->max) &&
+ !mas_slot_locked(r_mas, r_wr_mas->slots, r_mas->offset + 1)) {
+ r_mas->last = mas_safe_pivot(r_mas, r_wr_mas->pivots,
+ r_wr_mas->type, r_mas->offset + 1);
+ r_mas->offset++;
+ }
+}
+
+static inline void *mas_state_walk(struct ma_state *mas)
+{
+ void *entry;
+
+ entry = mas_start(mas);
+ if (mas_is_none(mas))
+ return NULL;
+
+ if (mas_is_ptr(mas))
+ return entry;
+
+ return mtree_range_walk(mas);
+}
+
+/*
+ * mtree_lookup_walk() - Internal quick lookup that does not keep maple state up
+ * to date.
+ *
+ * @mas: The maple state.
+ *
+ * Note: Leaves mas in undesirable state.
+ * Return: The entry for @mas->index or %NULL on dead node.
+ */
+static inline void *mtree_lookup_walk(struct ma_state *mas)
+{
+ unsigned long *pivots;
+ unsigned char offset;
+ struct maple_node *node;
+ struct maple_enode *next;
+ enum maple_type type;
+ void __rcu **slots;
+ unsigned char end;
+ unsigned long max;
+
+ next = mas->node;
+ max = ULONG_MAX;
+ do {
+ offset = 0;
+ node = mte_to_node(next);
+ type = mte_node_type(next);
+ pivots = ma_pivots(node, type);
+ end = ma_data_end(node, type, pivots, max);
+ if (unlikely(ma_dead_node(node)))
+ goto dead_node;
+ do {
+ if (pivots[offset] >= mas->index) {
+ max = pivots[offset];
+ break;
+ }
+ } while (++offset < end);
+
+ slots = ma_slots(node, type);
+ next = mt_slot(mas->tree, slots, offset);
+ if (unlikely(ma_dead_node(node)))
+ goto dead_node;
+ } while (!ma_is_leaf(type));
+
+ return (void *)next;
+
+dead_node:
+ mas_reset(mas);
+ return NULL;
+}
+
+static void mte_destroy_walk(struct maple_enode *, struct maple_tree *);
+/*
+ * mas_new_root() - Create a new root node that only contains the entry passed
+ * in.
+ * @mas: The maple state
+ * @entry: The entry to store.
+ *
+ * Only valid when the index == 0 and the last == ULONG_MAX
+ *
+ * Return 0 on error, 1 on success.
+ */
+static inline int mas_new_root(struct ma_state *mas, void *entry)
+{
+ struct maple_enode *root = mas_root_locked(mas);
+ enum maple_type type = maple_leaf_64;
+ struct maple_node *node;
+ void __rcu **slots;
+ unsigned long *pivots;
+
+ if (!entry && !mas->index && mas->last == ULONG_MAX) {
+ mas->depth = 0;
+ mas_set_height(mas);
+ rcu_assign_pointer(mas->tree->ma_root, entry);
+ mas->node = MAS_START;
+ goto done;
+ }
+
+ mas_node_count(mas, 1);
+ if (mas_is_err(mas))
+ return 0;
+
+ node = mas_pop_node(mas);
+ pivots = ma_pivots(node, type);
+ slots = ma_slots(node, type);
+ node->parent = ma_parent_ptr(mas_tree_parent(mas));
+ mas->node = mt_mk_node(node, type);
+ rcu_assign_pointer(slots[0], entry);
+ pivots[0] = mas->last;
+ mas->depth = 1;
+ mas_set_height(mas);
+ rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
+
+done:
+ if (xa_is_node(root))
+ mte_destroy_walk(root, mas->tree);
+
+ return 1;
+}
+/*
+ * mas_wr_spanning_store() - Create a subtree with the store operation completed
+ * and new nodes where necessary, then place the sub-tree in the actual tree.
+ * Note that mas is expected to point to the node which caused the store to
+ * span.
+ * @wr_mas: The maple write state
+ *
+ * Return: 0 on error, positive on success.
+ */
+static inline int mas_wr_spanning_store(struct ma_wr_state *wr_mas)
+{
+ struct maple_subtree_state mast;
+ struct maple_big_node b_node;
+ struct ma_state *mas;
+ unsigned char height;
+
+ /* Left and Right side of spanning store */
+ MA_STATE(l_mas, NULL, 0, 0);
+ MA_STATE(r_mas, NULL, 0, 0);
+ MA_WR_STATE(r_wr_mas, &r_mas, wr_mas->entry);
+ MA_WR_STATE(l_wr_mas, &l_mas, wr_mas->entry);
+
+ /*
+ * A store operation that spans multiple nodes is called a spanning
+ * store and is handled early in the store call stack by the function
+ * mas_is_span_wr(). When a spanning store is identified, the maple
+ * state is duplicated. The first maple state walks the left tree path
+ * to ``index``, the duplicate walks the right tree path to ``last``.
+ * The data in the two nodes are combined into a single node, two nodes,
+ * or possibly three nodes (see the 3-way split above). A ``NULL``
+ * written to the last entry of a node is considered a spanning store as
+ * a rebalance is required for the operation to complete and an overflow
+ * of data may happen.
+ */
+ mas = wr_mas->mas;
+ trace_ma_op(__func__, mas);
+
+ if (unlikely(!mas->index && mas->last == ULONG_MAX))
+ return mas_new_root(mas, wr_mas->entry);
+ /*
+ * Node rebalancing may occur due to this store, so there may be three new
+ * entries per level plus a new root.
+ */
+ height = mas_mt_height(mas);
+ mas_node_count(mas, 1 + height * 3);
+ if (mas_is_err(mas))
+ return 0;
+
+ /*
+ * Set up right side. Need to get to the next offset after the spanning
+ * store to ensure it's not NULL and to combine both the next node and
+ * the node with the start together.
+ */
+ r_mas = *mas;
+ /* Avoid overflow, walk to next slot in the tree. */
+ if (r_mas.last + 1)
+ r_mas.last++;
+
+ r_mas.index = r_mas.last;
+ mas_wr_walk_index(&r_wr_mas);
+ r_mas.last = r_mas.index = mas->last;
+
+ /* Set up left side. */
+ l_mas = *mas;
+ mas_wr_walk_index(&l_wr_mas);
+
+ if (!wr_mas->entry) {
+ mas_extend_spanning_null(&l_wr_mas, &r_wr_mas);
+ mas->offset = l_mas.offset;
+ mas->index = l_mas.index;
+ mas->last = l_mas.last = r_mas.last;
+ }
+
+ /* expanding NULLs may make this cover the entire range */
+ if (!l_mas.index && r_mas.last == ULONG_MAX) {
+ mas_set_range(mas, 0, ULONG_MAX);
+ return mas_new_root(mas, wr_mas->entry);
+ }
+
+ memset(&b_node, 0, sizeof(struct maple_big_node));
+ /* Copy l_mas and store the value in b_node. */
+ mas_store_b_node(&l_wr_mas, &b_node, l_wr_mas.node_end);
+ /* Copy r_mas into b_node. */
+ if (r_mas.offset <= r_wr_mas.node_end)
+ mas_mab_cp(&r_mas, r_mas.offset, r_wr_mas.node_end,
+ &b_node, b_node.b_end + 1);
+ else
+ b_node.b_end++;
+
+ /* Stop spanning searches by searching for just index. */
+ l_mas.index = l_mas.last = mas->index;
+
+ mast.bn = &b_node;
+ mast.orig_l = &l_mas;
+ mast.orig_r = &r_mas;
+ /* Combine l_mas and r_mas and split them up evenly again. */
+ return mas_spanning_rebalance(mas, &mast, height + 1);
+}
+
+/*
+ * mas_wr_node_store() - Attempt to store the value in a node
+ * @wr_mas: The maple write state
+ *
+ * Attempts to reuse the node, but may allocate.
+ *
+ * Return: True if stored, false otherwise
+ */
+static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas,
+ unsigned char new_end)
+{
+ struct ma_state *mas = wr_mas->mas;
+ void __rcu **dst_slots;
+ unsigned long *dst_pivots;
+ unsigned char dst_offset, offset_end = wr_mas->offset_end;
+ struct maple_node reuse, *newnode;
+ unsigned char copy_size, node_pivots = mt_pivots[wr_mas->type];
+ bool in_rcu = mt_in_rcu(mas->tree);
+
+ /* Check if there is enough data. The room is enough. */
+ if (!mte_is_root(mas->node) && (new_end <= mt_min_slots[wr_mas->type]) &&
+ !(mas->mas_flags & MA_STATE_BULK))
+ return false;
+
+ if (mas->last == wr_mas->end_piv)
+ offset_end++; /* don't copy this offset */
+ else if (unlikely(wr_mas->r_max == ULONG_MAX))
+ mas_bulk_rebalance(mas, wr_mas->node_end, wr_mas->type);
+
+ /* set up node. */
+ if (in_rcu) {
+ mas_node_count(mas, 1);
+ if (mas_is_err(mas))
+ return false;
+
+ newnode = mas_pop_node(mas);
+ } else {
+ memset(&reuse, 0, sizeof(struct maple_node));
+ newnode = &reuse;
+ }
+
+ newnode->parent = mas_mn(mas)->parent;
+ dst_pivots = ma_pivots(newnode, wr_mas->type);
+ dst_slots = ma_slots(newnode, wr_mas->type);
+ /* Copy from start to insert point */
+ memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset);
+ memcpy(dst_slots, wr_mas->slots, sizeof(void *) * mas->offset);
+
+ /* Handle insert of new range starting after old range */
+ if (wr_mas->r_min < mas->index) {
+ rcu_assign_pointer(dst_slots[mas->offset], wr_mas->content);
+ dst_pivots[mas->offset++] = mas->index - 1;
+ }
+
+ /* Store the new entry and range end. */
+ if (mas->offset < node_pivots)
+ dst_pivots[mas->offset] = mas->last;
+ rcu_assign_pointer(dst_slots[mas->offset], wr_mas->entry);
+
+ /*
+ * this range wrote to the end of the node or it overwrote the rest of
+ * the data
+ */
+ if (offset_end > wr_mas->node_end)
+ goto done;
+
+ dst_offset = mas->offset + 1;
+ /* Copy to the end of node if necessary. */
+ copy_size = wr_mas->node_end - offset_end + 1;
+ memcpy(dst_slots + dst_offset, wr_mas->slots + offset_end,
+ sizeof(void *) * copy_size);
+ memcpy(dst_pivots + dst_offset, wr_mas->pivots + offset_end,
+ sizeof(unsigned long) * (copy_size - 1));
+
+ if (new_end < node_pivots)
+ dst_pivots[new_end] = mas->max;
+
+done:
+ mas_leaf_set_meta(mas, newnode, dst_pivots, maple_leaf_64, new_end);
+ if (in_rcu) {
+ struct maple_enode *old_enode = mas->node;
+
+ mas->node = mt_mk_node(newnode, wr_mas->type);
+ mas_replace_node(mas, old_enode);
+ } else {
+ memcpy(wr_mas->node, newnode, sizeof(struct maple_node));
+ }
+ trace_ma_write(__func__, mas, 0, wr_mas->entry);
+ mas_update_gap(mas);
+ return true;
+}
+
+/*
+ * mas_wr_slot_store: Attempt to store a value in a slot.
+ * @wr_mas: the maple write state
+ *
+ * Return: True if stored, false otherwise
+ */
+static inline bool mas_wr_slot_store(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+ unsigned char offset = mas->offset;
+ void __rcu **slots = wr_mas->slots;
+ bool gap = false;
+
+ gap |= !mt_slot_locked(mas->tree, slots, offset);
+ gap |= !mt_slot_locked(mas->tree, slots, offset + 1);
+
+ if (wr_mas->offset_end - offset == 1) {
+ if (mas->index == wr_mas->r_min) {
+ /* Overwriting the range and a part of the next one */
+ rcu_assign_pointer(slots[offset], wr_mas->entry);
+ wr_mas->pivots[offset] = mas->last;
+ } else {
+ /* Overwriting a part of the range and the next one */
+ rcu_assign_pointer(slots[offset + 1], wr_mas->entry);
+ wr_mas->pivots[offset] = mas->index - 1;
+ mas->offset++; /* Keep mas accurate. */
+ }
+ } else if (!mt_in_rcu(mas->tree)) {
+ /*
+ * Expand the range, only partially overwriting the previous and
+ * next ranges
+ */
+ gap |= !mt_slot_locked(mas->tree, slots, offset + 2);
+ rcu_assign_pointer(slots[offset + 1], wr_mas->entry);
+ wr_mas->pivots[offset] = mas->index - 1;
+ wr_mas->pivots[offset + 1] = mas->last;
+ mas->offset++; /* Keep mas accurate. */
+ } else {
+ return false;
+ }
+
+ trace_ma_write(__func__, mas, 0, wr_mas->entry);
+ /*
+ * Only update gap when the new entry is empty or there is an empty
+ * entry in the original two ranges.
+ */
+ if (!wr_mas->entry || gap)
+ mas_update_gap(mas);
+
+ return true;
+}
+
+static inline void mas_wr_extend_null(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+
+ if (!wr_mas->slots[wr_mas->offset_end]) {
+ /* If this one is null, the next and prev are not */
+ mas->last = wr_mas->end_piv;
+ } else {
+ /* Check next slot(s) if we are overwriting the end */
+ if ((mas->last == wr_mas->end_piv) &&
+ (wr_mas->node_end != wr_mas->offset_end) &&
+ !wr_mas->slots[wr_mas->offset_end + 1]) {
+ wr_mas->offset_end++;
+ if (wr_mas->offset_end == wr_mas->node_end)
+ mas->last = mas->max;
+ else
+ mas->last = wr_mas->pivots[wr_mas->offset_end];
+ wr_mas->end_piv = mas->last;
+ }
+ }
+
+ if (!wr_mas->content) {
+ /* If this one is null, the next and prev are not */
+ mas->index = wr_mas->r_min;
+ } else {
+ /* Check prev slot if we are overwriting the start */
+ if (mas->index == wr_mas->r_min && mas->offset &&
+ !wr_mas->slots[mas->offset - 1]) {
+ mas->offset--;
+ wr_mas->r_min = mas->index =
+ mas_safe_min(mas, wr_mas->pivots, mas->offset);
+ wr_mas->r_max = wr_mas->pivots[mas->offset];
+ }
+ }
+}
+
+static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas)
+{
+ while ((wr_mas->offset_end < wr_mas->node_end) &&
+ (wr_mas->mas->last > wr_mas->pivots[wr_mas->offset_end]))
+ wr_mas->offset_end++;
+
+ if (wr_mas->offset_end < wr_mas->node_end)
+ wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end];
+ else
+ wr_mas->end_piv = wr_mas->mas->max;
+
+ if (!wr_mas->entry)
+ mas_wr_extend_null(wr_mas);
+}
+
+static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+ unsigned char new_end = wr_mas->node_end + 2;
+
+ new_end -= wr_mas->offset_end - mas->offset;
+ if (wr_mas->r_min == mas->index)
+ new_end--;
+
+ if (wr_mas->end_piv == mas->last)
+ new_end--;
+
+ return new_end;
+}
+
+/*
+ * mas_wr_append: Attempt to append
+ * @wr_mas: the maple write state
+ * @new_end: The end of the node after the modification
+ *
+ * This is currently unsafe in rcu mode since the end of the node may be cached
+ * by readers while the node contents may be updated which could result in
+ * inaccurate information.
+ *
+ * Return: True if appended, false otherwise
+ */
+static inline bool mas_wr_append(struct ma_wr_state *wr_mas,
+ unsigned char new_end)
+{
+ struct ma_state *mas;
+ void __rcu **slots;
+ unsigned char end;
+
+ mas = wr_mas->mas;
+ if (mt_in_rcu(mas->tree))
+ return false;
+
+ if (mas->offset != wr_mas->node_end)
+ return false;
+
+ end = wr_mas->node_end;
+ if (mas->offset != end)
+ return false;
+
+ if (new_end < mt_pivots[wr_mas->type]) {
+ wr_mas->pivots[new_end] = wr_mas->pivots[end];
+ ma_set_meta(wr_mas->node, wr_mas->type, 0, new_end);
+ }
+
+ slots = wr_mas->slots;
+ if (new_end == end + 1) {
+ if (mas->last == wr_mas->r_max) {
+ /* Append to end of range */
+ rcu_assign_pointer(slots[new_end], wr_mas->entry);
+ wr_mas->pivots[end] = mas->index - 1;
+ mas->offset = new_end;
+ } else {
+ /* Append to start of range */
+ rcu_assign_pointer(slots[new_end], wr_mas->content);
+ wr_mas->pivots[end] = mas->last;
+ rcu_assign_pointer(slots[end], wr_mas->entry);
+ }
+ } else {
+ /* Append to the range without touching any boundaries. */
+ rcu_assign_pointer(slots[new_end], wr_mas->content);
+ wr_mas->pivots[end + 1] = mas->last;
+ rcu_assign_pointer(slots[end + 1], wr_mas->entry);
+ wr_mas->pivots[end] = mas->index - 1;
+ mas->offset = end + 1;
+ }
+
+ if (!wr_mas->content || !wr_mas->entry)
+ mas_update_gap(mas);
+
+ trace_ma_write(__func__, mas, new_end, wr_mas->entry);
+ return true;
+}
+
+/*
+ * mas_wr_bnode() - Slow path for a modification.
+ * @wr_mas: The write maple state
+ *
+ * This is where split, rebalance end up.
+ */
+static void mas_wr_bnode(struct ma_wr_state *wr_mas)
+{
+ struct maple_big_node b_node;
+
+ trace_ma_write(__func__, wr_mas->mas, 0, wr_mas->entry);
+ memset(&b_node, 0, sizeof(struct maple_big_node));
+ mas_store_b_node(wr_mas, &b_node, wr_mas->offset_end);
+ mas_commit_b_node(wr_mas, &b_node, wr_mas->node_end);
+}
+
+static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+ unsigned char new_end;
+
+ /* Direct replacement */
+ if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) {
+ rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);
+ if (!!wr_mas->entry ^ !!wr_mas->content)
+ mas_update_gap(mas);
+ return;
+ }
+
+ /*
+ * new_end exceeds the size of the maple node and cannot enter the fast
+ * path.
+ */
+ new_end = mas_wr_new_end(wr_mas);
+ if (new_end >= mt_slots[wr_mas->type])
+ goto slow_path;
+
+ /* Attempt to append */
+ if (mas_wr_append(wr_mas, new_end))
+ return;
+
+ if (new_end == wr_mas->node_end && mas_wr_slot_store(wr_mas))
+ return;
+
+ if (mas_wr_node_store(wr_mas, new_end))
+ return;
+
+ if (mas_is_err(mas))
+ return;
+
+slow_path:
+ mas_wr_bnode(wr_mas);
+}
+
+/*
+ * mas_wr_store_entry() - Internal call to store a value
+ * @mas: The maple state
+ * @entry: The entry to store.
+ *
+ * Return: The contents that was stored at the index.
+ */
+static inline void *mas_wr_store_entry(struct ma_wr_state *wr_mas)
+{
+ struct ma_state *mas = wr_mas->mas;
+
+ wr_mas->content = mas_start(mas);
+ if (mas_is_none(mas) || mas_is_ptr(mas)) {
+ mas_store_root(mas, wr_mas->entry);
+ return wr_mas->content;
+ }
+
+ if (unlikely(!mas_wr_walk(wr_mas))) {
+ mas_wr_spanning_store(wr_mas);
+ return wr_mas->content;
+ }
+
+ /* At this point, we are at the leaf node that needs to be altered. */
+ mas_wr_end_piv(wr_mas);
+ /* New root for a single pointer */
+ if (unlikely(!mas->index && mas->last == ULONG_MAX)) {
+ mas_new_root(mas, wr_mas->entry);
+ return wr_mas->content;
+ }
+
+ mas_wr_modify(wr_mas);
+ return wr_mas->content;
+}
+
+/**
+ * mas_insert() - Internal call to insert a value
+ * @mas: The maple state
+ * @entry: The entry to store
+ *
+ * Return: %NULL or the contents that already exists at the requested index
+ * otherwise. The maple state needs to be checked for error conditions.
+ */
+static inline void *mas_insert(struct ma_state *mas, void *entry)
+{
+ MA_WR_STATE(wr_mas, mas, entry);
+
+ /*
+ * Inserting a new range inserts either 0, 1, or 2 pivots within the
+ * tree. If the insert fits exactly into an existing gap with a value
+ * of NULL, then the slot only needs to be written with the new value.
+ * If the range being inserted is adjacent to another range, then only a
+ * single pivot needs to be inserted (as well as writing the entry). If
+ * the new range is within a gap but does not touch any other ranges,
+ * then two pivots need to be inserted: the start - 1, and the end. As
+ * usual, the entry must be written. Most operations require a new node
+ * to be allocated and replace an existing node to ensure RCU safety,
+ * when in RCU mode. The exception to requiring a newly allocated node
+ * is when inserting at the end of a node (appending). When done
+ * carefully, appending can reuse the node in place.
+ */
+ wr_mas.content = mas_start(mas);
+ if (wr_mas.content)
+ goto exists;
+
+ if (mas_is_none(mas) || mas_is_ptr(mas)) {
+ mas_store_root(mas, entry);
+ return NULL;
+ }
+
+ /* spanning writes always overwrite something */
+ if (!mas_wr_walk(&wr_mas))
+ goto exists;
+
+ /* At this point, we are at the leaf node that needs to be altered. */
+ wr_mas.offset_end = mas->offset;
+ wr_mas.end_piv = wr_mas.r_max;
+
+ if (wr_mas.content || (mas->last > wr_mas.r_max))
+ goto exists;
+
+ if (!entry)
+ return NULL;
+
+ mas_wr_modify(&wr_mas);
+ return wr_mas.content;
+
+exists:
+ mas_set_err(mas, -EEXIST);
+ return wr_mas.content;
+
+}
+
+static inline void mas_rewalk(struct ma_state *mas, unsigned long index)
+{
+retry:
+ mas_set(mas, index);
+ mas_state_walk(mas);
+ if (mas_is_start(mas))
+ goto retry;
+}
+
+static inline bool mas_rewalk_if_dead(struct ma_state *mas,
+ struct maple_node *node, const unsigned long index)
+{
+ if (unlikely(ma_dead_node(node))) {
+ mas_rewalk(mas, index);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * mas_prev_node() - Find the prev non-null entry at the same level in the
+ * tree. The prev value will be mas->node[mas->offset] or MAS_NONE.
+ * @mas: The maple state
+ * @min: The lower limit to search
+ *
+ * The prev node value will be mas->node[mas->offset] or MAS_NONE.
+ * Return: 1 if the node is dead, 0 otherwise.
+ */
+static inline int mas_prev_node(struct ma_state *mas, unsigned long min)
+{
+ enum maple_type mt;
+ int offset, level;
+ void __rcu **slots;
+ struct maple_node *node;
+ unsigned long *pivots;
+ unsigned long max;
+
+ node = mas_mn(mas);
+ if (!mas->min)
+ goto no_entry;
+
+ max = mas->min - 1;
+ if (max < min)
+ goto no_entry;
+
+ level = 0;
+ do {
+ if (ma_is_root(node))
+ goto no_entry;
+
+ /* Walk up. */
+ if (unlikely(mas_ascend(mas)))
+ return 1;
+ offset = mas->offset;
+ level++;
+ node = mas_mn(mas);
+ } while (!offset);
+
+ offset--;
+ mt = mte_node_type(mas->node);
+ while (level > 1) {
+ level--;
+ slots = ma_slots(node, mt);
+ mas->node = mas_slot(mas, slots, offset);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ mt = mte_node_type(mas->node);
+ node = mas_mn(mas);
+ pivots = ma_pivots(node, mt);
+ offset = ma_data_end(node, mt, pivots, max);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+ }
+
+ slots = ma_slots(node, mt);
+ mas->node = mas_slot(mas, slots, offset);
+ pivots = ma_pivots(node, mt);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ if (likely(offset))
+ mas->min = pivots[offset - 1] + 1;
+ mas->max = max;
+ mas->offset = mas_data_end(mas);
+ if (unlikely(mte_dead_node(mas->node)))
+ return 1;
+
+ return 0;
+
+no_entry:
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ mas->node = MAS_NONE;
+ return 0;
+}
+
+/*
+ * mas_prev_slot() - Get the entry in the previous slot
+ *
+ * @mas: The maple state
+ * @max: The minimum starting range
+ * @empty: Can be empty
+ * @set_underflow: Set the @mas->node to underflow state on limit.
+ *
+ * Return: The entry in the previous slot which is possibly NULL
+ */
+static void *mas_prev_slot(struct ma_state *mas, unsigned long min, bool empty,
+ bool set_underflow)
+{
+ void *entry;
+ void __rcu **slots;
+ unsigned long pivot;
+ enum maple_type type;
+ unsigned long *pivots;
+ struct maple_node *node;
+ unsigned long save_point = mas->index;
+
+retry:
+ node = mas_mn(mas);
+ type = mte_node_type(mas->node);
+ pivots = ma_pivots(node, type);
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (mas->min <= min) {
+ pivot = mas_safe_min(mas, pivots, mas->offset);
+
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (pivot <= min)
+ goto underflow;
+ }
+
+again:
+ if (likely(mas->offset)) {
+ mas->offset--;
+ mas->last = mas->index - 1;
+ mas->index = mas_safe_min(mas, pivots, mas->offset);
+ } else {
+ if (mas_prev_node(mas, min)) {
+ mas_rewalk(mas, save_point);
+ goto retry;
+ }
+
+ if (mas_is_none(mas))
+ goto underflow;
+
+ mas->last = mas->max;
+ node = mas_mn(mas);
+ type = mte_node_type(mas->node);
+ pivots = ma_pivots(node, type);
+ mas->index = pivots[mas->offset - 1] + 1;
+ }
+
+ slots = ma_slots(node, type);
+ entry = mas_slot(mas, slots, mas->offset);
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (likely(entry))
+ return entry;
+
+ if (!empty) {
+ if (mas->index <= min)
+ goto underflow;
+
+ goto again;
+ }
+
+ return entry;
+
+underflow:
+ if (set_underflow)
+ mas->node = MAS_UNDERFLOW;
+ return NULL;
+}
+
+/*
+ * mas_next_node() - Get the next node at the same level in the tree.
+ * @mas: The maple state
+ * @max: The maximum pivot value to check.
+ *
+ * The next value will be mas->node[mas->offset] or MAS_NONE.
+ * Return: 1 on dead node, 0 otherwise.
+ */
+static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
+ unsigned long max)
+{
+ unsigned long min;
+ unsigned long *pivots;
+ struct maple_enode *enode;
+ int level = 0;
+ unsigned char node_end;
+ enum maple_type mt;
+ void __rcu **slots;
+
+ if (mas->max >= max)
+ goto no_entry;
+
+ min = mas->max + 1;
+ level = 0;
+ do {
+ if (ma_is_root(node))
+ goto no_entry;
+
+ /* Walk up. */
+ if (unlikely(mas_ascend(mas)))
+ return 1;
+
+ level++;
+ node = mas_mn(mas);
+ mt = mte_node_type(mas->node);
+ pivots = ma_pivots(node, mt);
+ node_end = ma_data_end(node, mt, pivots, mas->max);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ } while (unlikely(mas->offset == node_end));
+
+ slots = ma_slots(node, mt);
+ mas->offset++;
+ enode = mas_slot(mas, slots, mas->offset);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ if (level > 1)
+ mas->offset = 0;
+
+ while (unlikely(level > 1)) {
+ level--;
+ mas->node = enode;
+ node = mas_mn(mas);
+ mt = mte_node_type(mas->node);
+ slots = ma_slots(node, mt);
+ enode = mas_slot(mas, slots, 0);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+ }
+
+ if (!mas->offset)
+ pivots = ma_pivots(node, mt);
+
+ mas->max = mas_safe_pivot(mas, pivots, mas->offset, mt);
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ mas->node = enode;
+ mas->min = min;
+ return 0;
+
+no_entry:
+ if (unlikely(ma_dead_node(node)))
+ return 1;
+
+ mas->node = MAS_NONE;
+ return 0;
+}
+
+/*
+ * mas_next_slot() - Get the entry in the next slot
+ *
+ * @mas: The maple state
+ * @max: The maximum starting range
+ * @empty: Can be empty
+ * @set_overflow: Should @mas->node be set to overflow when the limit is
+ * reached.
+ *
+ * Return: The entry in the next slot which is possibly NULL
+ */
+static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty,
+ bool set_overflow)
+{
+ void __rcu **slots;
+ unsigned long *pivots;
+ unsigned long pivot;
+ enum maple_type type;
+ struct maple_node *node;
+ unsigned char data_end;
+ unsigned long save_point = mas->last;
+ void *entry;
+
+retry:
+ node = mas_mn(mas);
+ type = mte_node_type(mas->node);
+ pivots = ma_pivots(node, type);
+ data_end = ma_data_end(node, type, pivots, mas->max);
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (mas->max >= max) {
+ if (likely(mas->offset < data_end))
+ pivot = pivots[mas->offset];
+ else
+ goto overflow;
+
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (pivot >= max)
+ goto overflow;
+ }
+
+ if (likely(mas->offset < data_end)) {
+ mas->index = pivots[mas->offset] + 1;
+again:
+ mas->offset++;
+ if (likely(mas->offset < data_end))
+ mas->last = pivots[mas->offset];
+ else
+ mas->last = mas->max;
+ } else {
+ if (mas_next_node(mas, node, max)) {
+ mas_rewalk(mas, save_point);
+ goto retry;
+ }
+
+ if (WARN_ON_ONCE(mas_is_none(mas))) {
+ mas->node = MAS_OVERFLOW;
+ return NULL;
+ goto overflow;
+ }
+
+ mas->offset = 0;
+ mas->index = mas->min;
+ node = mas_mn(mas);
+ type = mte_node_type(mas->node);
+ pivots = ma_pivots(node, type);
+ mas->last = pivots[0];
+ }
+
+ slots = ma_slots(node, type);
+ entry = mt_slot(mas->tree, slots, mas->offset);
+ if (unlikely(mas_rewalk_if_dead(mas, node, save_point)))
+ goto retry;
+
+ if (entry)
+ return entry;
+
+ if (!empty) {
+ if (mas->last >= max)
+ goto overflow;
+
+ mas->index = mas->last + 1;
+ /* Node cannot end on NULL, so it's safe to short-cut here */
+ goto again;
+ }
+
+ return entry;
+
+overflow:
+ if (set_overflow)
+ mas->node = MAS_OVERFLOW;
+ return NULL;
+}
+
+/*
+ * mas_next_entry() - Internal function to get the next entry.
+ * @mas: The maple state
+ * @limit: The maximum range start.
+ *
+ * Set the @mas->node to the next entry and the range_start to
+ * the beginning value for the entry. Does not check beyond @limit.
+ * Sets @mas->index and @mas->last to the range, Does not update @mas->index and
+ * @mas->last on overflow.
+ * Restarts on dead nodes.
+ *
+ * Return: the next entry or %NULL.
+ */
+static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit)
+{
+ if (mas->last >= limit) {
+ mas->node = MAS_OVERFLOW;
+ return NULL;
+ }
+
+ return mas_next_slot(mas, limit, false, true);
+}
+
+/*
+ * mas_rev_awalk() - Internal function. Reverse allocation walk. Find the
+ * highest gap address of a given size in a given node and descend.
+ * @mas: The maple state
+ * @size: The needed size.
+ *
+ * Return: True if found in a leaf, false otherwise.
+ *
+ */
+static bool mas_rev_awalk(struct ma_state *mas, unsigned long size,
+ unsigned long *gap_min, unsigned long *gap_max)
+{
+ enum maple_type type = mte_node_type(mas->node);
+ struct maple_node *node = mas_mn(mas);
+ unsigned long *pivots, *gaps;
+ void __rcu **slots;
+ unsigned long gap = 0;
+ unsigned long max, min;
+ unsigned char offset;
+
+ if (unlikely(mas_is_err(mas)))
+ return true;
+
+ if (ma_is_dense(type)) {
+ /* dense nodes. */
+ mas->offset = (unsigned char)(mas->index - mas->min);
+ return true;
+ }
+
+ pivots = ma_pivots(node, type);
+ slots = ma_slots(node, type);
+ gaps = ma_gaps(node, type);
+ offset = mas->offset;
+ min = mas_safe_min(mas, pivots, offset);
+ /* Skip out of bounds. */
+ while (mas->last < min)
+ min = mas_safe_min(mas, pivots, --offset);
+
+ max = mas_safe_pivot(mas, pivots, offset, type);
+ while (mas->index <= max) {
+ gap = 0;
+ if (gaps)
+ gap = gaps[offset];
+ else if (!mas_slot(mas, slots, offset))
+ gap = max - min + 1;
+
+ if (gap) {
+ if ((size <= gap) && (size <= mas->last - min + 1))
+ break;
+
+ if (!gaps) {
+ /* Skip the next slot, it cannot be a gap. */
+ if (offset < 2)
+ goto ascend;
+
+ offset -= 2;
+ max = pivots[offset];
+ min = mas_safe_min(mas, pivots, offset);
+ continue;
+ }
+ }
+
+ if (!offset)
+ goto ascend;
+
+ offset--;
+ max = min - 1;
+ min = mas_safe_min(mas, pivots, offset);
+ }
+
+ if (unlikely((mas->index > max) || (size - 1 > max - mas->index)))
+ goto no_space;
+
+ if (unlikely(ma_is_leaf(type))) {
+ mas->offset = offset;
+ *gap_min = min;
+ *gap_max = min + gap - 1;
+ return true;
+ }
+
+ /* descend, only happens under lock. */
+ mas->node = mas_slot(mas, slots, offset);
+ mas->min = min;
+ mas->max = max;
+ mas->offset = mas_data_end(mas);
+ return false;
+
+ascend:
+ if (!mte_is_root(mas->node))
+ return false;
+
+no_space:
+ mas_set_err(mas, -EBUSY);
+ return false;
+}
+
+static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size)
+{
+ enum maple_type type = mte_node_type(mas->node);
+ unsigned long pivot, min, gap = 0;
+ unsigned char offset, data_end;
+ unsigned long *gaps, *pivots;
+ void __rcu **slots;
+ struct maple_node *node;
+ bool found = false;
+
+ if (ma_is_dense(type)) {
+ mas->offset = (unsigned char)(mas->index - mas->min);
+ return true;
+ }
+
+ node = mas_mn(mas);
+ pivots = ma_pivots(node, type);
+ slots = ma_slots(node, type);
+ gaps = ma_gaps(node, type);
+ offset = mas->offset;
+ min = mas_safe_min(mas, pivots, offset);
+ data_end = ma_data_end(node, type, pivots, mas->max);
+ for (; offset <= data_end; offset++) {
+ pivot = mas_safe_pivot(mas, pivots, offset, type);
+
+ /* Not within lower bounds */
+ if (mas->index > pivot)
+ goto next_slot;
+
+ if (gaps)
+ gap = gaps[offset];
+ else if (!mas_slot(mas, slots, offset))
+ gap = min(pivot, mas->last) - max(mas->index, min) + 1;
+ else
+ goto next_slot;
+
+ if (gap >= size) {
+ if (ma_is_leaf(type)) {
+ found = true;
+ goto done;
+ }
+ if (mas->index <= pivot) {
+ mas->node = mas_slot(mas, slots, offset);
+ mas->min = min;
+ mas->max = pivot;
+ offset = 0;
+ break;
+ }
+ }
+next_slot:
+ min = pivot + 1;
+ if (mas->last <= pivot) {
+ mas_set_err(mas, -EBUSY);
+ return true;
+ }
+ }
+
+ if (mte_is_root(mas->node))
+ found = true;
+done:
+ mas->offset = offset;
+ return found;
+}
+
+/**
+ * mas_walk() - Search for @mas->index in the tree.
+ * @mas: The maple state.
+ *
+ * mas->index and mas->last will be set to the range if there is a value. If
+ * mas->node is MAS_NONE, reset to MAS_START.
+ *
+ * Return: the entry at the location or %NULL.
+ */
+void *mas_walk(struct ma_state *mas)
+{
+ void *entry;
+
+ if (!mas_is_active(mas) || !mas_is_start(mas))
+ mas->node = MAS_START;
+retry:
+ entry = mas_state_walk(mas);
+ if (mas_is_start(mas)) {
+ goto retry;
+ } else if (mas_is_none(mas)) {
+ mas->index = 0;
+ mas->last = ULONG_MAX;
+ } else if (mas_is_ptr(mas)) {
+ if (!mas->index) {
+ mas->last = 0;
+ return entry;
+ }
+
+ mas->index = 1;
+ mas->last = ULONG_MAX;
+ mas->node = MAS_NONE;
+ return NULL;
+ }
+
+ return entry;
+}
+EXPORT_SYMBOL_GPL(mas_walk);
+
+static inline bool mas_rewind_node(struct ma_state *mas)
+{
+ unsigned char slot;
+
+ do {
+ if (mte_is_root(mas->node)) {
+ slot = mas->offset;
+ if (!slot)
+ return false;
+ } else {
+ mas_ascend(mas);
+ slot = mas->offset;
+ }
+ } while (!slot);
+
+ mas->offset = --slot;
+ return true;
+}
+
+/*
+ * mas_skip_node() - Internal function. Skip over a node.
+ * @mas: The maple state.
+ *
+ * Return: true if there is another node, false otherwise.
+ */
+static inline bool mas_skip_node(struct ma_state *mas)
+{
+ if (mas_is_err(mas))
+ return false;
+
+ do {
+ if (mte_is_root(mas->node)) {
+ if (mas->offset >= mas_data_end(mas)) {
+ mas_set_err(mas, -EBUSY);
+ return false;
+ }
+ } else {
+ mas_ascend(mas);
+ }
+ } while (mas->offset >= mas_data_end(mas));
+
+ mas->offset++;
+ return true;
+}
+
+/*
+ * mas_awalk() - Allocation walk. Search from low address to high, for a gap of
+ * @size
+ * @mas: The maple state
+ * @size: The size of the gap required
+ *
+ * Search between @mas->index and @mas->last for a gap of @size.
+ */
+static inline void mas_awalk(struct ma_state *mas, unsigned long size)
+{
+ struct maple_enode *last = NULL;
+
+ /*
+ * There are 4 options:
+ * go to child (descend)
+ * go back to parent (ascend)
+ * no gap found. (return, slot == MAPLE_NODE_SLOTS)
+ * found the gap. (return, slot != MAPLE_NODE_SLOTS)
+ */
+ while (!mas_is_err(mas) && !mas_anode_descend(mas, size)) {
+ if (last == mas->node)
+ mas_skip_node(mas);
+ else
+ last = mas->node;
+ }
+}
+
+/*
+ * mas_sparse_area() - Internal function. Return upper or lower limit when
+ * searching for a gap in an empty tree.
+ * @mas: The maple state
+ * @min: the minimum range
+ * @max: The maximum range
+ * @size: The size of the gap
+ * @fwd: Searching forward or back
+ */
+static inline int mas_sparse_area(struct ma_state *mas, unsigned long min,
+ unsigned long max, unsigned long size, bool fwd)
+{
+ if (!unlikely(mas_is_none(mas)) && min == 0) {
+ min++;
+ /*
+ * At this time, min is increased, we need to recheck whether
+ * the size is satisfied.
+ */
+ if (min > max || max - min + 1 < size)
+ return -EBUSY;
+ }
+ /* mas_is_ptr */
+
+ if (fwd) {
+ mas->index = min;
+ mas->last = min + size - 1;
+ } else {
+ mas->last = max;
+ mas->index = max - size + 1;
+ }
+ return 0;
+}
+
+/*
+ * mas_empty_area() - Get the lowest address within the range that is
+ * sufficient for the size requested.
+ * @mas: The maple state
+ * @min: The lowest value of the range
+ * @max: The highest value of the range
+ * @size: The size needed
+ */
+int mas_empty_area(struct ma_state *mas, unsigned long min,
+ unsigned long max, unsigned long size)
+{
+ unsigned char offset;
+ unsigned long *pivots;
+ enum maple_type mt;
+
+ if (min > max)
+ return -EINVAL;
+
+ if (size == 0 || max - min < size - 1)
+ return -EINVAL;
+
+ if (mas_is_start(mas))
+ mas_start(mas);
+ else if (mas->offset >= 2)
+ mas->offset -= 2;
+ else if (!mas_skip_node(mas))
+ return -EBUSY;
+
+ /* Empty set */
+ if (mas_is_none(mas) || mas_is_ptr(mas))
+ return mas_sparse_area(mas, min, max, size, true);
+
+ /* The start of the window can only be within these values */
+ mas->index = min;
+ mas->last = max;
+ mas_awalk(mas, size);
+
+ if (unlikely(mas_is_err(mas)))
+ return xa_err(mas->node);
+
+ offset = mas->offset;
+ if (unlikely(offset == MAPLE_NODE_SLOTS))
+ return -EBUSY;
+
+ mt = mte_node_type(mas->node);
+ pivots = ma_pivots(mas_mn(mas), mt);
+ min = mas_safe_min(mas, pivots, offset);
+ if (mas->index < min)
+ mas->index = min;
+ mas->last = mas->index + size - 1;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mas_empty_area);
+
+/*
+ * mas_empty_area_rev() - Get the highest address within the range that is
+ * sufficient for the size requested.
+ * @mas: The maple state
+ * @min: The lowest value of the range
+ * @max: The highest value of the range
+ * @size: The size needed
+ */
+int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
+ unsigned long max, unsigned long size)
+{
+ struct maple_enode *last = mas->node;
+
+ if (min > max)
+ return -EINVAL;
+
+ if (size == 0 || max - min < size - 1)
+ return -EINVAL;
+
+ if (mas_is_start(mas)) {
+ mas_start(mas);
+ mas->offset = mas_data_end(mas);
+ } else if (mas->offset >= 2) {
+ mas->offset -= 2;
+ } else if (!mas_rewind_node(mas)) {
+ return -EBUSY;
+ }
+
+ /* Empty set. */
+ if (mas_is_none(mas) || mas_is_ptr(mas))
+ return mas_sparse_area(mas, min, max, size, false);
+
+ /* The start of the window can only be within these values. */
+ mas->index = min;
+ mas->last = max;
+
+ while (!mas_rev_awalk(mas, size, &min, &max)) {
+ if (last == mas->node) {
+ if (!mas_rewind_node(mas))
+ return -EBUSY;
+ } else {
+ last = mas->node;
+ }
+ }
+
+ if (mas_is_err(mas))
+ return xa_err(mas->node);
+
+ if (unlikely(mas->offset == MAPLE_NODE_SLOTS))
+ return -EBUSY;
+
+ /* Trim the upper limit to the max. */
+ if (max < mas->last)
+ mas->last = max;
+
+ mas->index = mas->last - size + 1;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mas_empty_area_rev);
+
+/*
+ * mte_dead_leaves() - Mark all leaves of a node as dead.
+ * @mas: The maple state
+ * @slots: Pointer to the slot array
+ * @type: The maple node type
+ *
+ * Must hold the write lock.
+ *
+ * Return: The number of leaves marked as dead.
+ */
+static inline
+unsigned char mte_dead_leaves(struct maple_enode *enode, struct maple_tree *mt,
+ void __rcu **slots)
+{
+ struct maple_node *node;
+ enum maple_type type;
+ void *entry;
+ int offset;
+
+ for (offset = 0; offset < mt_slot_count(enode); offset++) {
+ entry = mt_slot(mt, slots, offset);
+ type = mte_node_type(entry);
+ node = mte_to_node(entry);
+ /* Use both node and type to catch LE & BE metadata */
+ if (!node || !type)
+ break;
+
+ mte_set_node_dead(entry);
+ node->type = type;
+ rcu_assign_pointer(slots[offset], node);
+ }
+
+ return offset;
+}
+
+/**
+ * mte_dead_walk() - Walk down a dead tree to just before the leaves
+ * @enode: The maple encoded node
+ * @offset: The starting offset
+ *
+ * Note: This can only be used from the RCU callback context.
+ */
+static void __rcu **mte_dead_walk(struct maple_enode **enode, unsigned char offset)
+{
+ struct maple_node *node, *next;
+ void __rcu **slots = NULL;
+
+ next = mte_to_node(*enode);
+ do {
+ *enode = ma_enode_ptr(next);
+ node = mte_to_node(*enode);
+ slots = ma_slots(node, node->type);
+ next = rcu_dereference_protected(slots[offset],
+ lock_is_held(&rcu_callback_map));
+ offset = 0;
+ } while (!ma_is_leaf(next->type));
+
+ return slots;
+}
+
+/**
+ * mt_free_walk() - Walk & free a tree in the RCU callback context
+ * @head: The RCU head that's within the node.
+ *
+ * Note: This can only be used from the RCU callback context.
+ */
+static void mt_free_walk(struct rcu_head *head)
+{
+ void __rcu **slots;
+ struct maple_node *node, *start;
+ struct maple_enode *enode;
+ unsigned char offset;
+ enum maple_type type;
+
+ node = container_of(head, struct maple_node, rcu);
+
+ if (ma_is_leaf(node->type))
+ goto free_leaf;
+
+ start = node;
+ enode = mt_mk_node(node, node->type);
+ slots = mte_dead_walk(&enode, 0);
+ node = mte_to_node(enode);
+ do {
+ mt_free_bulk(node->slot_len, slots);
+ offset = node->parent_slot + 1;
+ enode = node->piv_parent;
+ if (mte_to_node(enode) == node)
+ goto free_leaf;
+
+ type = mte_node_type(enode);
+ slots = ma_slots(mte_to_node(enode), type);
+ if ((offset < mt_slots[type]) &&
+ rcu_dereference_protected(slots[offset],
+ lock_is_held(&rcu_callback_map)))
+ slots = mte_dead_walk(&enode, offset);
+ node = mte_to_node(enode);
+ } while ((node != start) || (node->slot_len < offset));
+
+ slots = ma_slots(node, node->type);
+ mt_free_bulk(node->slot_len, slots);
+
+free_leaf:
+ mt_free_rcu(&node->rcu);
+}
+
+static inline void __rcu **mte_destroy_descend(struct maple_enode **enode,
+ struct maple_tree *mt, struct maple_enode *prev, unsigned char offset)
+{
+ struct maple_node *node;
+ struct maple_enode *next = *enode;
+ void __rcu **slots = NULL;
+ enum maple_type type;
+ unsigned char next_offset = 0;
+
+ do {
+ *enode = next;
+ node = mte_to_node(*enode);
+ type = mte_node_type(*enode);
+ slots = ma_slots(node, type);
+ next = mt_slot_locked(mt, slots, next_offset);
+ if ((mte_dead_node(next)))
+ next = mt_slot_locked(mt, slots, ++next_offset);
+
+ mte_set_node_dead(*enode);
+ node->type = type;
+ node->piv_parent = prev;
+ node->parent_slot = offset;
+ offset = next_offset;
+ next_offset = 0;
+ prev = *enode;
+ } while (!mte_is_leaf(next));
+
+ return slots;
+}
+
+static void mt_destroy_walk(struct maple_enode *enode, struct maple_tree *mt,
+ bool free)
+{
+ void __rcu **slots;
+ struct maple_node *node = mte_to_node(enode);
+ struct maple_enode *start;
+
+ if (mte_is_leaf(enode)) {
+ node->type = mte_node_type(enode);
+ goto free_leaf;
+ }
+
+ start = enode;
+ slots = mte_destroy_descend(&enode, mt, start, 0);
+ node = mte_to_node(enode); // Updated in the above call.
+ do {
+ enum maple_type type;
+ unsigned char offset;
+ struct maple_enode *parent, *tmp;
+
+ node->slot_len = mte_dead_leaves(enode, mt, slots);
+ if (free)
+ mt_free_bulk(node->slot_len, slots);
+ offset = node->parent_slot + 1;
+ enode = node->piv_parent;
+ if (mte_to_node(enode) == node)
+ goto free_leaf;
+
+ type = mte_node_type(enode);
+ slots = ma_slots(mte_to_node(enode), type);
+ if (offset >= mt_slots[type])
+ goto next;
+
+ tmp = mt_slot_locked(mt, slots, offset);
+ if (mte_node_type(tmp) && mte_to_node(tmp)) {
+ parent = enode;
+ enode = tmp;
+ slots = mte_destroy_descend(&enode, mt, parent, offset);
+ }
+next:
+ node = mte_to_node(enode);
+ } while (start != enode);
+
+ node = mte_to_node(enode);
+ node->slot_len = mte_dead_leaves(enode, mt, slots);
+ if (free)
+ mt_free_bulk(node->slot_len, slots);
+
+free_leaf:
+ if (free)
+ mt_free_rcu(&node->rcu);
+ else
+ mt_clear_meta(mt, node, node->type);
+}
+
+/*
+ * mte_destroy_walk() - Free a tree or sub-tree.
+ * @enode: the encoded maple node (maple_enode) to start
+ * @mt: the tree to free - needed for node types.
+ *
+ * Must hold the write lock.
+ */
+static inline void mte_destroy_walk(struct maple_enode *enode,
+ struct maple_tree *mt)
+{
+ struct maple_node *node = mte_to_node(enode);
+
+ if (mt_in_rcu(mt)) {
+ mt_destroy_walk(enode, mt, false);
+ call_rcu(&node->rcu, mt_free_walk);
+ } else {
+ mt_destroy_walk(enode, mt, true);
+ }
+}
+
+static void mas_wr_store_setup(struct ma_wr_state *wr_mas)
+{
+ if (!mas_is_active(wr_mas->mas)) {
+ if (mas_is_start(wr_mas->mas))
+ return;
+
+ if (unlikely(mas_is_paused(wr_mas->mas)))
+ goto reset;
+
+ if (unlikely(mas_is_none(wr_mas->mas)))
+ goto reset;
+
+ if (unlikely(mas_is_overflow(wr_mas->mas)))
+ goto reset;
+
+ if (unlikely(mas_is_underflow(wr_mas->mas)))
+ goto reset;
+ }
+
+ /*
+ * A less strict version of mas_is_span_wr() where we allow spanning
+ * writes within this node. This is to stop partial walks in
+ * mas_prealloc() from being reset.
+ */
+ if (wr_mas->mas->last > wr_mas->mas->max)
+ goto reset;
+
+ if (wr_mas->entry)
+ return;
+
+ if (mte_is_leaf(wr_mas->mas->node) &&
+ wr_mas->mas->last == wr_mas->mas->max)
+ goto reset;
+
+ return;
+
+reset:
+ mas_reset(wr_mas->mas);
+}
+
+/* Interface */
+
+/**
+ * mas_store() - Store an @entry.
+ * @mas: The maple state.
+ * @entry: The entry to store.
+ *
+ * The @mas->index and @mas->last is used to set the range for the @entry.
+ * Note: The @mas should have pre-allocated entries to ensure there is memory to
+ * store the entry. Please see mas_expected_entries()/mas_destroy() for more details.
+ *
+ * Return: the first entry between mas->index and mas->last or %NULL.
+ */
+void *mas_store(struct ma_state *mas, void *entry)
+{
+ MA_WR_STATE(wr_mas, mas, entry);
+
+ trace_ma_write(__func__, mas, 0, entry);
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+ if (MAS_WARN_ON(mas, mas->index > mas->last))
+ pr_err("Error %lX > %lX %p\n", mas->index, mas->last, entry);
+
+ if (mas->index > mas->last) {
+ mas_set_err(mas, -EINVAL);
+ return NULL;
+ }
+
+#endif
+
+ /*
+ * Storing is the same operation as insert with the added caveat that it
+ * can overwrite entries. Although this seems simple enough, one may
+ * want to examine what happens if a single store operation was to
+ * overwrite multiple entries within a self-balancing B-Tree.
+ */
+ mas_wr_store_setup(&wr_mas);
+ mas_wr_store_entry(&wr_mas);
+ return wr_mas.content;
+}
+EXPORT_SYMBOL_GPL(mas_store);
+
+/**
+ * mas_store_gfp() - Store a value into the tree.
+ * @mas: The maple state
+ * @entry: The entry to store
+ * @gfp: The GFP_FLAGS to use for allocations if necessary.
+ *
+ * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
+ * be allocated.
+ */
+int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
+{
+ MA_WR_STATE(wr_mas, mas, entry);
+
+ mas_wr_store_setup(&wr_mas);
+ trace_ma_write(__func__, mas, 0, entry);
+retry:
+ mas_wr_store_entry(&wr_mas);
+ if (unlikely(mas_nomem(mas, gfp)))
+ goto retry;
+
+ if (unlikely(mas_is_err(mas)))
+ return xa_err(mas->node);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mas_store_gfp);
+
+/**
+ * mas_store_prealloc() - Store a value into the tree using memory
+ * preallocated in the maple state.
+ * @mas: The maple state
+ * @entry: The entry to store.
+ */
+void mas_store_prealloc(struct ma_state *mas, void *entry)
+{
+ MA_WR_STATE(wr_mas, mas, entry);
+
+ mas_wr_store_setup(&wr_mas);
+ trace_ma_write(__func__, mas, 0, entry);
+ mas_wr_store_entry(&wr_mas);
+ MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas));
+ mas_destroy(mas);
+}
+EXPORT_SYMBOL_GPL(mas_store_prealloc);
+
+/**
+ * mas_preallocate() - Preallocate enough nodes for a store operation
+ * @mas: The maple state
+ * @entry: The entry that will be stored
+ * @gfp: The GFP_FLAGS to use for allocations.
+ *
+ * Return: 0 on success, -ENOMEM if memory could not be allocated.
+ */
+int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
+{
+ MA_WR_STATE(wr_mas, mas, entry);
+ unsigned char node_size;
+ int request = 1;
+ int ret;
+
+
+ if (unlikely(!mas->index && mas->last == ULONG_MAX))
+ goto ask_now;
+
+ mas_wr_store_setup(&wr_mas);
+ wr_mas.content = mas_start(mas);
+ /* Root expand */
+ if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
+ goto ask_now;
+
+ if (unlikely(!mas_wr_walk(&wr_mas))) {
+ /* Spanning store, use worst case for now */
+ request = 1 + mas_mt_height(mas) * 3;
+ goto ask_now;
+ }
+
+ /* At this point, we are at the leaf node that needs to be altered. */
+ /* Exact fit, no nodes needed. */
+ if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
+ return 0;
+
+ mas_wr_end_piv(&wr_mas);
+ node_size = mas_wr_new_end(&wr_mas);
+
+ /* Slot store, does not require additional nodes */
+ if (node_size == wr_mas.node_end) {
+ /* reuse node */
+ if (!mt_in_rcu(mas->tree))
+ return 0;
+ /* shifting boundary */
+ if (wr_mas.offset_end - mas->offset == 1)
+ return 0;
+ }
+
+ if (node_size >= mt_slots[wr_mas.type]) {
+ /* Split, worst case for now. */
+ request = 1 + mas_mt_height(mas) * 2;
+ goto ask_now;
+ }
+
+ /* New root needs a singe node */
+ if (unlikely(mte_is_root(mas->node)))
+ goto ask_now;
+
+ /* Potential spanning rebalance collapsing a node, use worst-case */
+ if (node_size - 1 <= mt_min_slots[wr_mas.type])
+ request = mas_mt_height(mas) * 2 - 1;
+
+ /* node store, slot store needs one node */
+ask_now:
+ mas_node_count_gfp(mas, request, gfp);
+ mas->mas_flags |= MA_STATE_PREALLOC;
+ if (likely(!mas_is_err(mas)))
+ return 0;
+
+ mas_set_alloc_req(mas, 0);
+ ret = xa_err(mas->node);
+ mas_reset(mas);
+ mas_destroy(mas);
+ mas_reset(mas);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mas_preallocate);
+
+/*
+ * mas_destroy() - destroy a maple state.
+ * @mas: The maple state
+ *
+ * Upon completion, check the left-most node and rebalance against the node to
+ * the right if necessary. Frees any allocated nodes associated with this maple
+ * state.
+ */
+void mas_destroy(struct ma_state *mas)
+{
+ struct maple_alloc *node;
+ unsigned long total;
+
+ /*
+ * When using mas_for_each() to insert an expected number of elements,
+ * it is possible that the number inserted is less than the expected
+ * number. To fix an invalid final node, a check is performed here to
+ * rebalance the previous node with the final node.
+ */
+ if (mas->mas_flags & MA_STATE_REBALANCE) {
+ unsigned char end;
+
+ mas_start(mas);
+ mtree_range_walk(mas);
+ end = mas_data_end(mas) + 1;
+ if (end < mt_min_slot_count(mas->node) - 1)
+ mas_destroy_rebalance(mas, end);
+
+ mas->mas_flags &= ~MA_STATE_REBALANCE;
+ }
+ mas->mas_flags &= ~(MA_STATE_BULK|MA_STATE_PREALLOC);
+
+ total = mas_allocated(mas);
+ while (total) {
+ node = mas->alloc;
+ mas->alloc = node->slot[0];
+ if (node->node_count > 1) {
+ size_t count = node->node_count - 1;
+
+ mt_free_bulk(count, (void __rcu **)&node->slot[1]);
+ total -= count;
+ }
+ kmem_cache_free(maple_node_cache, node);
+ total--;
+ }
+
+ mas->alloc = NULL;
+}
+EXPORT_SYMBOL_GPL(mas_destroy);
+
+/*
+ * mas_expected_entries() - Set the expected number of entries that will be inserted.
+ * @mas: The maple state
+ * @nr_entries: The number of expected entries.
+ *
+ * This will attempt to pre-allocate enough nodes to store the expected number
+ * of entries. The allocations will occur using the bulk allocator interface
+ * for speed. Please call mas_destroy() on the @mas after inserting the entries
+ * to ensure any unused nodes are freed.
+ *
+ * Return: 0 on success, -ENOMEM if memory could not be allocated.
+ */
+int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries)
+{
+ int nonleaf_cap = MAPLE_ARANGE64_SLOTS - 2;
+ struct maple_enode *enode = mas->node;
+ int nr_nodes;
+ int ret;
+
+ /*
+ * Sometimes it is necessary to duplicate a tree to a new tree, such as
+ * forking a process and duplicating the VMAs from one tree to a new
+ * tree. When such a situation arises, it is known that the new tree is
+ * not going to be used until the entire tree is populated. For
+ * performance reasons, it is best to use a bulk load with RCU disabled.
+ * This allows for optimistic splitting that favours the left and reuse
+ * of nodes during the operation.
+ */
+
+ /* Optimize splitting for bulk insert in-order */
+ mas->mas_flags |= MA_STATE_BULK;
+
+ /*
+ * Avoid overflow, assume a gap between each entry and a trailing null.
+ * If this is wrong, it just means allocation can happen during
+ * insertion of entries.
+ */
+ nr_nodes = max(nr_entries, nr_entries * 2 + 1);
+ if (!mt_is_alloc(mas->tree))
+ nonleaf_cap = MAPLE_RANGE64_SLOTS - 2;
+
+ /* Leaves; reduce slots to keep space for expansion */
+ nr_nodes = DIV_ROUND_UP(nr_nodes, MAPLE_RANGE64_SLOTS - 2);
+ /* Internal nodes */
+ nr_nodes += DIV_ROUND_UP(nr_nodes, nonleaf_cap);
+ /* Add working room for split (2 nodes) + new parents */
+ mas_node_count_gfp(mas, nr_nodes + 3, GFP_KERNEL);
+
+ /* Detect if allocations run out */
+ mas->mas_flags |= MA_STATE_PREALLOC;
+
+ if (!mas_is_err(mas))
+ return 0;
+
+ ret = xa_err(mas->node);
+ mas->node = enode;
+ mas_destroy(mas);
+ return ret;
+
+}
+EXPORT_SYMBOL_GPL(mas_expected_entries);
+
+static inline bool mas_next_setup(struct ma_state *mas, unsigned long max,
+ void **entry)
+{
+ bool was_none = mas_is_none(mas);
+
+ if (unlikely(mas->last >= max)) {
+ mas->node = MAS_OVERFLOW;
+ return true;
+ }
+
+ if (mas_is_active(mas))
+ return false;
+
+ if (mas_is_none(mas) || mas_is_paused(mas)) {
+ mas->node = MAS_START;
+ } else if (mas_is_overflow(mas)) {
+ /* Overflowed before, but the max changed */
+ mas->node = MAS_START;
+ } else if (mas_is_underflow(mas)) {
+ mas->node = MAS_START;
+ *entry = mas_walk(mas);
+ if (*entry)
+ return true;
+ }
+
+ if (mas_is_start(mas))
+ *entry = mas_walk(mas); /* Retries on dead nodes handled by mas_walk */
+
+ if (mas_is_ptr(mas)) {
+ *entry = NULL;
+ if (was_none && mas->index == 0) {
+ mas->index = mas->last = 0;
+ return true;
+ }
+ mas->index = 1;
+ mas->last = ULONG_MAX;
+ mas->node = MAS_NONE;
+ return true;
+ }
+
+ if (mas_is_none(mas))
+ return true;
+
+ return false;
+}
+
+/**
+ * mas_next() - Get the next entry.
+ * @mas: The maple state
+ * @max: The maximum index to check.
+ *
+ * Returns the next entry after @mas->index.
+ * Must hold rcu_read_lock or the write lock.
+ * Can return the zero entry.
+ *
+ * Return: The next entry or %NULL
+ */
+void *mas_next(struct ma_state *mas, unsigned long max)
+{
+ void *entry = NULL;
+
+ if (mas_next_setup(mas, max, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_next_slot */
+ return mas_next_slot(mas, max, false, true);
+}
+EXPORT_SYMBOL_GPL(mas_next);
+
+/**
+ * mas_next_range() - Advance the maple state to the next range
+ * @mas: The maple state
+ * @max: The maximum index to check.
+ *
+ * Sets @mas->index and @mas->last to the range.
+ * Must hold rcu_read_lock or the write lock.
+ * Can return the zero entry.
+ *
+ * Return: The next entry or %NULL
+ */
+void *mas_next_range(struct ma_state *mas, unsigned long max)
+{
+ void *entry = NULL;
+
+ if (mas_next_setup(mas, max, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_next_slot */
+ return mas_next_slot(mas, max, true, true);
+}
+EXPORT_SYMBOL_GPL(mas_next_range);
+
+/**
+ * mt_next() - get the next value in the maple tree
+ * @mt: The maple tree
+ * @index: The start index
+ * @max: The maximum index to check
+ *
+ * Takes RCU read lock internally to protect the search, which does not
+ * protect the returned pointer after dropping RCU read lock.
+ * See also: Documentation/core-api/maple_tree.rst
+ *
+ * Return: The entry higher than @index or %NULL if nothing is found.
+ */
+void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max)
+{
+ void *entry = NULL;
+ MA_STATE(mas, mt, index, index);
+
+ rcu_read_lock();
+ entry = mas_next(&mas, max);
+ rcu_read_unlock();
+ return entry;
+}
+EXPORT_SYMBOL_GPL(mt_next);
+
+static inline bool mas_prev_setup(struct ma_state *mas, unsigned long min,
+ void **entry)
+{
+ if (unlikely(mas->index <= min)) {
+ mas->node = MAS_UNDERFLOW;
+ return true;
+ }
+
+ if (mas_is_active(mas))
+ return false;
+
+ if (mas_is_overflow(mas)) {
+ mas->node = MAS_START;
+ *entry = mas_walk(mas);
+ if (*entry)
+ return true;
+ }
+
+ if (mas_is_none(mas) || mas_is_paused(mas)) {
+ mas->node = MAS_START;
+ } else if (mas_is_underflow(mas)) {
+ /* underflowed before but the min changed */
+ mas->node = MAS_START;
+ }
+
+ if (mas_is_start(mas))
+ mas_walk(mas);
+
+ if (unlikely(mas_is_ptr(mas))) {
+ if (!mas->index)
+ goto none;
+ mas->index = mas->last = 0;
+ *entry = mas_root(mas);
+ return true;
+ }
+
+ if (mas_is_none(mas)) {
+ if (mas->index) {
+ /* Walked to out-of-range pointer? */
+ mas->index = mas->last = 0;
+ mas->node = MAS_ROOT;
+ *entry = mas_root(mas);
+ return true;
+ }
+ return true;
+ }
+
+ return false;
+
+none:
+ mas->node = MAS_NONE;
+ return true;
+}
+
+/**
+ * mas_prev() - Get the previous entry
+ * @mas: The maple state
+ * @min: The minimum value to check.
+ *
+ * Must hold rcu_read_lock or the write lock.
+ * Will reset mas to MAS_START if the node is MAS_NONE. Will stop on not
+ * searchable nodes.
+ *
+ * Return: the previous value or %NULL.
+ */
+void *mas_prev(struct ma_state *mas, unsigned long min)
+{
+ void *entry = NULL;
+
+ if (mas_prev_setup(mas, min, &entry))
+ return entry;
+
+ return mas_prev_slot(mas, min, false, true);
+}
+EXPORT_SYMBOL_GPL(mas_prev);
+
+/**
+ * mas_prev_range() - Advance to the previous range
+ * @mas: The maple state
+ * @min: The minimum value to check.
+ *
+ * Sets @mas->index and @mas->last to the range.
+ * Must hold rcu_read_lock or the write lock.
+ * Will reset mas to MAS_START if the node is MAS_NONE. Will stop on not
+ * searchable nodes.
+ *
+ * Return: the previous value or %NULL.
+ */
+void *mas_prev_range(struct ma_state *mas, unsigned long min)
+{
+ void *entry = NULL;
+
+ if (mas_prev_setup(mas, min, &entry))
+ return entry;
+
+ return mas_prev_slot(mas, min, true, true);
+}
+EXPORT_SYMBOL_GPL(mas_prev_range);
+
+/**
+ * mt_prev() - get the previous value in the maple tree
+ * @mt: The maple tree
+ * @index: The start index
+ * @min: The minimum index to check
+ *
+ * Takes RCU read lock internally to protect the search, which does not
+ * protect the returned pointer after dropping RCU read lock.
+ * See also: Documentation/core-api/maple_tree.rst
+ *
+ * Return: The entry before @index or %NULL if nothing is found.
+ */
+void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min)
+{
+ void *entry = NULL;
+ MA_STATE(mas, mt, index, index);
+
+ rcu_read_lock();
+ entry = mas_prev(&mas, min);
+ rcu_read_unlock();
+ return entry;
+}
+EXPORT_SYMBOL_GPL(mt_prev);
+
+/**
+ * mas_pause() - Pause a mas_find/mas_for_each to drop the lock.
+ * @mas: The maple state to pause
+ *
+ * Some users need to pause a walk and drop the lock they're holding in
+ * order to yield to a higher priority thread or carry out an operation
+ * on an entry. Those users should call this function before they drop
+ * the lock. It resets the @mas to be suitable for the next iteration
+ * of the loop after the user has reacquired the lock. If most entries
+ * found during a walk require you to call mas_pause(), the mt_for_each()
+ * iterator may be more appropriate.
+ *
+ */
+void mas_pause(struct ma_state *mas)
+{
+ mas->node = MAS_PAUSE;
+}
+EXPORT_SYMBOL_GPL(mas_pause);
+
+/**
+ * mas_find_setup() - Internal function to set up mas_find*().
+ * @mas: The maple state
+ * @max: The maximum index
+ * @entry: Pointer to the entry
+ *
+ * Returns: True if entry is the answer, false otherwise.
+ */
+static inline bool mas_find_setup(struct ma_state *mas, unsigned long max,
+ void **entry)
+{
+ if (mas_is_active(mas)) {
+ if (mas->last < max)
+ return false;
+
+ return true;
+ }
+
+ if (mas_is_paused(mas)) {
+ if (unlikely(mas->last >= max))
+ return true;
+
+ mas->index = ++mas->last;
+ mas->node = MAS_START;
+ } else if (mas_is_none(mas)) {
+ if (unlikely(mas->last >= max))
+ return true;
+
+ mas->index = mas->last;
+ mas->node = MAS_START;
+ } else if (mas_is_overflow(mas) || mas_is_underflow(mas)) {
+ if (mas->index > max) {
+ mas->node = MAS_OVERFLOW;
+ return true;
+ }
+
+ mas->node = MAS_START;
+ }
+
+ if (mas_is_start(mas)) {
+ /* First run or continue */
+ if (mas->index > max)
+ return true;
+
+ *entry = mas_walk(mas);
+ if (*entry)
+ return true;
+
+ }
+
+ if (unlikely(!mas_searchable(mas))) {
+ if (unlikely(mas_is_ptr(mas)))
+ goto ptr_out_of_range;
+
+ return true;
+ }
+
+ if (mas->index == max)
+ return true;
+
+ return false;
+
+ptr_out_of_range:
+ mas->node = MAS_NONE;
+ mas->index = 1;
+ mas->last = ULONG_MAX;
+ return true;
+}
+
+/**
+ * mas_find() - On the first call, find the entry at or after mas->index up to
+ * %max. Otherwise, find the entry after mas->index.
+ * @mas: The maple state
+ * @max: The maximum value to check.
+ *
+ * Must hold rcu_read_lock or the write lock.
+ * If an entry exists, last and index are updated accordingly.
+ * May set @mas->node to MAS_NONE.
+ *
+ * Return: The entry or %NULL.
+ */
+void *mas_find(struct ma_state *mas, unsigned long max)
+{
+ void *entry = NULL;
+
+ if (mas_find_setup(mas, max, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_next_slot */
+ return mas_next_slot(mas, max, false, false);
+}
+EXPORT_SYMBOL_GPL(mas_find);
+
+/**
+ * mas_find_range() - On the first call, find the entry at or after
+ * mas->index up to %max. Otherwise, advance to the next slot mas->index.
+ * @mas: The maple state
+ * @max: The maximum value to check.
+ *
+ * Must hold rcu_read_lock or the write lock.
+ * If an entry exists, last and index are updated accordingly.
+ * May set @mas->node to MAS_NONE.
+ *
+ * Return: The entry or %NULL.
+ */
+void *mas_find_range(struct ma_state *mas, unsigned long max)
+{
+ void *entry = NULL;
+
+ if (mas_find_setup(mas, max, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_next_slot */
+ return mas_next_slot(mas, max, true, false);
+}
+EXPORT_SYMBOL_GPL(mas_find_range);
+
+/**
+ * mas_find_rev_setup() - Internal function to set up mas_find_*_rev()
+ * @mas: The maple state
+ * @min: The minimum index
+ * @entry: Pointer to the entry
+ *
+ * Returns: True if entry is the answer, false otherwise.
+ */
+static inline bool mas_find_rev_setup(struct ma_state *mas, unsigned long min,
+ void **entry)
+{
+ if (mas_is_active(mas)) {
+ if (mas->index > min)
+ return false;
+
+ return true;
+ }
+
+ if (mas_is_paused(mas)) {
+ if (unlikely(mas->index <= min)) {
+ mas->node = MAS_NONE;
+ return true;
+ }
+ mas->node = MAS_START;
+ mas->last = --mas->index;
+ } else if (mas_is_none(mas)) {
+ if (mas->index <= min)
+ goto none;
+
+ mas->last = mas->index;
+ mas->node = MAS_START;
+ } else if (mas_is_underflow(mas) || mas_is_overflow(mas)) {
+ if (mas->last <= min) {
+ mas->node = MAS_UNDERFLOW;
+ return true;
+ }
+
+ mas->node = MAS_START;
+ }
+
+ if (mas_is_start(mas)) {
+ /* First run or continue */
+ if (mas->index < min)
+ return true;
+
+ *entry = mas_walk(mas);
+ if (*entry)
+ return true;
+ }
+
+ if (unlikely(!mas_searchable(mas))) {
+ if (mas_is_ptr(mas))
+ goto none;
+
+ if (mas_is_none(mas)) {
+ /*
+ * Walked to the location, and there was nothing so the
+ * previous location is 0.
+ */
+ mas->last = mas->index = 0;
+ mas->node = MAS_ROOT;
+ *entry = mas_root(mas);
+ return true;
+ }
+ }
+
+ if (mas->index < min)
+ return true;
+
+ return false;
+
+none:
+ mas->node = MAS_NONE;
+ return true;
+}
+
+/**
+ * mas_find_rev: On the first call, find the first non-null entry at or below
+ * mas->index down to %min. Otherwise find the first non-null entry below
+ * mas->index down to %min.
+ * @mas: The maple state
+ * @min: The minimum value to check.
+ *
+ * Must hold rcu_read_lock or the write lock.
+ * If an entry exists, last and index are updated accordingly.
+ * May set @mas->node to MAS_NONE.
+ *
+ * Return: The entry or %NULL.
+ */
+void *mas_find_rev(struct ma_state *mas, unsigned long min)
+{
+ void *entry = NULL;
+
+ if (mas_find_rev_setup(mas, min, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_prev_slot */
+ return mas_prev_slot(mas, min, false, false);
+
+}
+EXPORT_SYMBOL_GPL(mas_find_rev);
+
+/**
+ * mas_find_range_rev: On the first call, find the first non-null entry at or
+ * below mas->index down to %min. Otherwise advance to the previous slot after
+ * mas->index down to %min.
+ * @mas: The maple state
+ * @min: The minimum value to check.
+ *
+ * Must hold rcu_read_lock or the write lock.
+ * If an entry exists, last and index are updated accordingly.
+ * May set @mas->node to MAS_NONE.
+ *
+ * Return: The entry or %NULL.
+ */
+void *mas_find_range_rev(struct ma_state *mas, unsigned long min)
+{
+ void *entry = NULL;
+
+ if (mas_find_rev_setup(mas, min, &entry))
+ return entry;
+
+ /* Retries on dead nodes handled by mas_prev_slot */
+ return mas_prev_slot(mas, min, true, false);
+}
+EXPORT_SYMBOL_GPL(mas_find_range_rev);
+
+/**
+ * mas_erase() - Find the range in which index resides and erase the entire
+ * range.
+ * @mas: The maple state
+ *
+ * Must hold the write lock.
+ * Searches for @mas->index, sets @mas->index and @mas->last to the range and
+ * erases that range.
+ *
+ * Return: the entry that was erased or %NULL, @mas->index and @mas->last are updated.
+ */
+void *mas_erase(struct ma_state *mas)
+{
+ void *entry;
+ MA_WR_STATE(wr_mas, mas, NULL);
+
+ if (mas_is_none(mas) || mas_is_paused(mas))
+ mas->node = MAS_START;
+
+ /* Retry unnecessary when holding the write lock. */
+ entry = mas_state_walk(mas);
+ if (!entry)
+ return NULL;
+
+write_retry:
+ /* Must reset to ensure spanning writes of last slot are detected */
+ mas_reset(mas);
+ mas_wr_store_setup(&wr_mas);
+ mas_wr_store_entry(&wr_mas);
+ if (mas_nomem(mas, GFP_KERNEL))
+ goto write_retry;
+
+ return entry;
+}
+EXPORT_SYMBOL_GPL(mas_erase);
+
+/**
+ * mas_nomem() - Check if there was an error allocating and do the allocation
+ * if necessary If there are allocations, then free them.
+ * @mas: The maple state
+ * @gfp: The GFP_FLAGS to use for allocations
+ * Return: true on allocation, false otherwise.
+ */
+bool mas_nomem(struct ma_state *mas, gfp_t gfp)
+ __must_hold(mas->tree->ma_lock)
+{
+ if (likely(mas->node != MA_ERROR(-ENOMEM))) {
+ mas_destroy(mas);
+ return false;
+ }
+
+ if (gfpflags_allow_blocking(gfp) && !mt_external_lock(mas->tree)) {
+ mtree_unlock(mas->tree);
+ mas_alloc_nodes(mas, gfp);
+ mtree_lock(mas->tree);
+ } else {
+ mas_alloc_nodes(mas, gfp);
+ }
+
+ if (!mas_allocated(mas))
+ return false;
+
+ mas->node = MAS_START;
+ return true;
+}
+
+void __init maple_tree_init(void)
+{
+ maple_node_cache = kmem_cache_create("maple_node",
+ sizeof(struct maple_node), sizeof(struct maple_node),
+ SLAB_PANIC, NULL);
+}
+
+/**
+ * mtree_load() - Load a value stored in a maple tree
+ * @mt: The maple tree
+ * @index: The index to load
+ *
+ * Return: the entry or %NULL
+ */
+void *mtree_load(struct maple_tree *mt, unsigned long index)
+{
+ MA_STATE(mas, mt, index, index);
+ void *entry;
+
+ trace_ma_read(__func__, &mas);
+ rcu_read_lock();
+retry:
+ entry = mas_start(&mas);
+ if (unlikely(mas_is_none(&mas)))
+ goto unlock;
+
+ if (unlikely(mas_is_ptr(&mas))) {
+ if (index)
+ entry = NULL;
+
+ goto unlock;
+ }
+
+ entry = mtree_lookup_walk(&mas);
+ if (!entry && unlikely(mas_is_start(&mas)))
+ goto retry;
+unlock:
+ rcu_read_unlock();
+ if (xa_is_zero(entry))
+ return NULL;
+
+ return entry;
+}
+EXPORT_SYMBOL(mtree_load);
+
+/**
+ * mtree_store_range() - Store an entry at a given range.
+ * @mt: The maple tree
+ * @index: The start of the range
+ * @last: The end of the range
+ * @entry: The entry to store
+ * @gfp: The GFP_FLAGS to use for allocations
+ *
+ * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
+ * be allocated.
+ */
+int mtree_store_range(struct maple_tree *mt, unsigned long index,
+ unsigned long last, void *entry, gfp_t gfp)
+{
+ MA_STATE(mas, mt, index, last);
+ MA_WR_STATE(wr_mas, &mas, entry);
+
+ trace_ma_write(__func__, &mas, 0, entry);
+ if (WARN_ON_ONCE(xa_is_advanced(entry)))
+ return -EINVAL;
+
+ if (index > last)
+ return -EINVAL;
+
+ mtree_lock(mt);
+retry:
+ mas_wr_store_entry(&wr_mas);
+ if (mas_nomem(&mas, gfp))
+ goto retry;
+
+ mtree_unlock(mt);
+ if (mas_is_err(&mas))
+ return xa_err(mas.node);
+
+ return 0;
+}
+EXPORT_SYMBOL(mtree_store_range);
+
+/**
+ * mtree_store() - Store an entry at a given index.
+ * @mt: The maple tree
+ * @index: The index to store the value
+ * @entry: The entry to store
+ * @gfp: The GFP_FLAGS to use for allocations
+ *
+ * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not
+ * be allocated.
+ */
+int mtree_store(struct maple_tree *mt, unsigned long index, void *entry,
+ gfp_t gfp)
+{
+ return mtree_store_range(mt, index, index, entry, gfp);
+}
+EXPORT_SYMBOL(mtree_store);
+
+/**
+ * mtree_insert_range() - Insert an entry at a given range if there is no value.
+ * @mt: The maple tree
+ * @first: The start of the range
+ * @last: The end of the range
+ * @entry: The entry to store
+ * @gfp: The GFP_FLAGS to use for allocations.
+ *
+ * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid
+ * request, -ENOMEM if memory could not be allocated.
+ */
+int mtree_insert_range(struct maple_tree *mt, unsigned long first,
+ unsigned long last, void *entry, gfp_t gfp)
+{
+ MA_STATE(ms, mt, first, last);
+
+ if (WARN_ON_ONCE(xa_is_advanced(entry)))
+ return -EINVAL;
+
+ if (first > last)
+ return -EINVAL;
+
+ mtree_lock(mt);
+retry:
+ mas_insert(&ms, entry);
+ if (mas_nomem(&ms, gfp))
+ goto retry;
+
+ mtree_unlock(mt);
+ if (mas_is_err(&ms))
+ return xa_err(ms.node);
+
+ return 0;
+}
+EXPORT_SYMBOL(mtree_insert_range);
+
+/**
+ * mtree_insert() - Insert an entry at a given index if there is no value.
+ * @mt: The maple tree
+ * @index : The index to store the value
+ * @entry: The entry to store
+ * @gfp: The GFP_FLAGS to use for allocations.
+ *
+ * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid
+ * request, -ENOMEM if memory could not be allocated.
+ */
+int mtree_insert(struct maple_tree *mt, unsigned long index, void *entry,
+ gfp_t gfp)
+{
+ return mtree_insert_range(mt, index, index, entry, gfp);
+}
+EXPORT_SYMBOL(mtree_insert);
+
+int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
+ void *entry, unsigned long size, unsigned long min,
+ unsigned long max, gfp_t gfp)
+{
+ int ret = 0;
+
+ MA_STATE(mas, mt, 0, 0);
+ if (!mt_is_alloc(mt))
+ return -EINVAL;
+
+ if (WARN_ON_ONCE(mt_is_reserved(entry)))
+ return -EINVAL;
+
+ mtree_lock(mt);
+retry:
+ ret = mas_empty_area(&mas, min, max, size);
+ if (ret)
+ goto unlock;
+
+ mas_insert(&mas, entry);
+ /*
+ * mas_nomem() may release the lock, causing the allocated area
+ * to be unavailable, so try to allocate a free area again.
+ */
+ if (mas_nomem(&mas, gfp))
+ goto retry;
+
+ if (mas_is_err(&mas))
+ ret = xa_err(mas.node);
+ else
+ *startp = mas.index;
+
+unlock:
+ mtree_unlock(mt);
+ return ret;
+}
+EXPORT_SYMBOL(mtree_alloc_range);
+
+int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
+ void *entry, unsigned long size, unsigned long min,
+ unsigned long max, gfp_t gfp)
+{
+ int ret = 0;
+
+ MA_STATE(mas, mt, 0, 0);
+ if (!mt_is_alloc(mt))
+ return -EINVAL;
+
+ if (WARN_ON_ONCE(mt_is_reserved(entry)))
+ return -EINVAL;
+
+ mtree_lock(mt);
+retry:
+ ret = mas_empty_area_rev(&mas, min, max, size);
+ if (ret)
+ goto unlock;
+
+ mas_insert(&mas, entry);
+ /*
+ * mas_nomem() may release the lock, causing the allocated area
+ * to be unavailable, so try to allocate a free area again.
+ */
+ if (mas_nomem(&mas, gfp))
+ goto retry;
+
+ if (mas_is_err(&mas))
+ ret = xa_err(mas.node);
+ else
+ *startp = mas.index;
+
+unlock:
+ mtree_unlock(mt);
+ return ret;
+}
+EXPORT_SYMBOL(mtree_alloc_rrange);
+
+/**
+ * mtree_erase() - Find an index and erase the entire range.
+ * @mt: The maple tree
+ * @index: The index to erase
+ *
+ * Erasing is the same as a walk to an entry then a store of a NULL to that
+ * ENTIRE range. In fact, it is implemented as such using the advanced API.
+ *
+ * Return: The entry stored at the @index or %NULL
+ */
+void *mtree_erase(struct maple_tree *mt, unsigned long index)
+{
+ void *entry = NULL;
+
+ MA_STATE(mas, mt, index, index);
+ trace_ma_op(__func__, &mas);
+
+ mtree_lock(mt);
+ entry = mas_erase(&mas);
+ mtree_unlock(mt);
+
+ return entry;
+}
+EXPORT_SYMBOL(mtree_erase);
+
+/**
+ * __mt_destroy() - Walk and free all nodes of a locked maple tree.
+ * @mt: The maple tree
+ *
+ * Note: Does not handle locking.
+ */
+void __mt_destroy(struct maple_tree *mt)
+{
+ void *root = mt_root_locked(mt);
+
+ rcu_assign_pointer(mt->ma_root, NULL);
+ if (xa_is_node(root))
+ mte_destroy_walk(root, mt);
+
+ mt->ma_flags = 0;
+}
+EXPORT_SYMBOL_GPL(__mt_destroy);
+
+/**
+ * mtree_destroy() - Destroy a maple tree
+ * @mt: The maple tree
+ *
+ * Frees all resources used by the tree. Handles locking.
+ */
+void mtree_destroy(struct maple_tree *mt)
+{
+ mtree_lock(mt);
+ __mt_destroy(mt);
+ mtree_unlock(mt);
+}
+EXPORT_SYMBOL(mtree_destroy);
+
+/**
+ * mt_find() - Search from the start up until an entry is found.
+ * @mt: The maple tree
+ * @index: Pointer which contains the start location of the search
+ * @max: The maximum value of the search range
+ *
+ * Takes RCU read lock internally to protect the search, which does not
+ * protect the returned pointer after dropping RCU read lock.
+ * See also: Documentation/core-api/maple_tree.rst
+ *
+ * In case that an entry is found @index is updated to point to the next
+ * possible entry independent whether the found entry is occupying a
+ * single index or a range if indices.
+ *
+ * Return: The entry at or after the @index or %NULL
+ */
+void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max)
+{
+ MA_STATE(mas, mt, *index, *index);
+ void *entry;
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+ unsigned long copy = *index;
+#endif
+
+ trace_ma_read(__func__, &mas);
+
+ if ((*index) > max)
+ return NULL;
+
+ rcu_read_lock();
+retry:
+ entry = mas_state_walk(&mas);
+ if (mas_is_start(&mas))
+ goto retry;
+
+ if (unlikely(xa_is_zero(entry)))
+ entry = NULL;
+
+ if (entry)
+ goto unlock;
+
+ while (mas_searchable(&mas) && (mas.last < max)) {
+ entry = mas_next_entry(&mas, max);
+ if (likely(entry && !xa_is_zero(entry)))
+ break;
+ }
+
+ if (unlikely(xa_is_zero(entry)))
+ entry = NULL;
+unlock:
+ rcu_read_unlock();
+ if (likely(entry)) {
+ *index = mas.last + 1;
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+ if (MT_WARN_ON(mt, (*index) && ((*index) <= copy)))
+ pr_err("index not increased! %lx <= %lx\n",
+ *index, copy);
+#endif
+ }
+
+ return entry;
+}
+EXPORT_SYMBOL(mt_find);
+
+/**
+ * mt_find_after() - Search from the start up until an entry is found.
+ * @mt: The maple tree
+ * @index: Pointer which contains the start location of the search
+ * @max: The maximum value to check
+ *
+ * Same as mt_find() except that it checks @index for 0 before
+ * searching. If @index == 0, the search is aborted. This covers a wrap
+ * around of @index to 0 in an iterator loop.
+ *
+ * Return: The entry at or after the @index or %NULL
+ */
+void *mt_find_after(struct maple_tree *mt, unsigned long *index,
+ unsigned long max)
+{
+ if (!(*index))
+ return NULL;
+
+ return mt_find(mt, index, max);
+}
+EXPORT_SYMBOL(mt_find_after);
+
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+atomic_t maple_tree_tests_run;
+EXPORT_SYMBOL_GPL(maple_tree_tests_run);
+atomic_t maple_tree_tests_passed;
+EXPORT_SYMBOL_GPL(maple_tree_tests_passed);
+
+#ifndef __KERNEL__
+extern void kmem_cache_set_non_kernel(struct kmem_cache *, unsigned int);
+void mt_set_non_kernel(unsigned int val)
+{
+ kmem_cache_set_non_kernel(maple_node_cache, val);
+}
+
+extern unsigned long kmem_cache_get_alloc(struct kmem_cache *);
+unsigned long mt_get_alloc_size(void)
+{
+ return kmem_cache_get_alloc(maple_node_cache);
+}
+
+extern void kmem_cache_zero_nr_tallocated(struct kmem_cache *);
+void mt_zero_nr_tallocated(void)
+{
+ kmem_cache_zero_nr_tallocated(maple_node_cache);
+}
+
+extern unsigned int kmem_cache_nr_tallocated(struct kmem_cache *);
+unsigned int mt_nr_tallocated(void)
+{
+ return kmem_cache_nr_tallocated(maple_node_cache);
+}
+
+extern unsigned int kmem_cache_nr_allocated(struct kmem_cache *);
+unsigned int mt_nr_allocated(void)
+{
+ return kmem_cache_nr_allocated(maple_node_cache);
+}
+
+/*
+ * mas_dead_node() - Check if the maple state is pointing to a dead node.
+ * @mas: The maple state
+ * @index: The index to restore in @mas.
+ *
+ * Used in test code.
+ * Return: 1 if @mas has been reset to MAS_START, 0 otherwise.
+ */
+static inline int mas_dead_node(struct ma_state *mas, unsigned long index)
+{
+ if (unlikely(!mas_searchable(mas) || mas_is_start(mas)))
+ return 0;
+
+ if (likely(!mte_dead_node(mas->node)))
+ return 0;
+
+ mas_rewalk(mas, index);
+ return 1;
+}
+
+void mt_cache_shrink(void)
+{
+}
+#else
+/*
+ * mt_cache_shrink() - For testing, don't use this.
+ *
+ * Certain testcases can trigger an OOM when combined with other memory
+ * debugging configuration options. This function is used to reduce the
+ * possibility of an out of memory even due to kmem_cache objects remaining
+ * around for longer than usual.
+ */
+void mt_cache_shrink(void)
+{
+ kmem_cache_shrink(maple_node_cache);
+
+}
+EXPORT_SYMBOL_GPL(mt_cache_shrink);
+
+#endif /* not defined __KERNEL__ */
+/*
+ * mas_get_slot() - Get the entry in the maple state node stored at @offset.
+ * @mas: The maple state
+ * @offset: The offset into the slot array to fetch.
+ *
+ * Return: The entry stored at @offset.
+ */
+static inline struct maple_enode *mas_get_slot(struct ma_state *mas,
+ unsigned char offset)
+{
+ return mas_slot(mas, ma_slots(mas_mn(mas), mte_node_type(mas->node)),
+ offset);
+}
+
+/* Depth first search, post-order */
+static void mas_dfs_postorder(struct ma_state *mas, unsigned long max)
+{
+
+ struct maple_enode *p = MAS_NONE, *mn = mas->node;
+ unsigned long p_min, p_max;
+
+ mas_next_node(mas, mas_mn(mas), max);
+ if (!mas_is_none(mas))
+ return;
+
+ if (mte_is_root(mn))
+ return;
+
+ mas->node = mn;
+ mas_ascend(mas);
+ do {
+ p = mas->node;
+ p_min = mas->min;
+ p_max = mas->max;
+ mas_prev_node(mas, 0);
+ } while (!mas_is_none(mas));
+
+ mas->node = p;
+ mas->max = p_max;
+ mas->min = p_min;
+}
+
+/* Tree validations */
+static void mt_dump_node(const struct maple_tree *mt, void *entry,
+ unsigned long min, unsigned long max, unsigned int depth,
+ enum mt_dump_format format);
+static void mt_dump_range(unsigned long min, unsigned long max,
+ unsigned int depth, enum mt_dump_format format)
+{
+ static const char spaces[] = " ";
+
+ switch(format) {
+ case mt_dump_hex:
+ if (min == max)
+ pr_info("%.*s%lx: ", depth * 2, spaces, min);
+ else
+ pr_info("%.*s%lx-%lx: ", depth * 2, spaces, min, max);
+ break;
+ default:
+ case mt_dump_dec:
+ if (min == max)
+ pr_info("%.*s%lu: ", depth * 2, spaces, min);
+ else
+ pr_info("%.*s%lu-%lu: ", depth * 2, spaces, min, max);
+ }
+}
+
+static void mt_dump_entry(void *entry, unsigned long min, unsigned long max,
+ unsigned int depth, enum mt_dump_format format)
+{
+ mt_dump_range(min, max, depth, format);
+
+ if (xa_is_value(entry))
+ pr_cont("value %ld (0x%lx) [%p]\n", xa_to_value(entry),
+ xa_to_value(entry), entry);
+ else if (xa_is_zero(entry))
+ pr_cont("zero (%ld)\n", xa_to_internal(entry));
+ else if (mt_is_reserved(entry))
+ pr_cont("UNKNOWN ENTRY (%p)\n", entry);
+ else
+ pr_cont("%p\n", entry);
+}
+
+static void mt_dump_range64(const struct maple_tree *mt, void *entry,
+ unsigned long min, unsigned long max, unsigned int depth,
+ enum mt_dump_format format)
+{
+ struct maple_range_64 *node = &mte_to_node(entry)->mr64;
+ bool leaf = mte_is_leaf(entry);
+ unsigned long first = min;
+ int i;
+
+ pr_cont(" contents: ");
+ for (i = 0; i < MAPLE_RANGE64_SLOTS - 1; i++) {
+ switch(format) {
+ case mt_dump_hex:
+ pr_cont("%p %lX ", node->slot[i], node->pivot[i]);
+ break;
+ default:
+ case mt_dump_dec:
+ pr_cont("%p %lu ", node->slot[i], node->pivot[i]);
+ }
+ }
+ pr_cont("%p\n", node->slot[i]);
+ for (i = 0; i < MAPLE_RANGE64_SLOTS; i++) {
+ unsigned long last = max;
+
+ if (i < (MAPLE_RANGE64_SLOTS - 1))
+ last = node->pivot[i];
+ else if (!node->slot[i] && max != mt_node_max(entry))
+ break;
+ if (last == 0 && i > 0)
+ break;
+ if (leaf)
+ mt_dump_entry(mt_slot(mt, node->slot, i),
+ first, last, depth + 1, format);
+ else if (node->slot[i])
+ mt_dump_node(mt, mt_slot(mt, node->slot, i),
+ first, last, depth + 1, format);
+
+ if (last == max)
+ break;
+ if (last > max) {
+ switch(format) {
+ case mt_dump_hex:
+ pr_err("node %p last (%lx) > max (%lx) at pivot %d!\n",
+ node, last, max, i);
+ break;
+ default:
+ case mt_dump_dec:
+ pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n",
+ node, last, max, i);
+ }
+ }
+ first = last + 1;
+ }
+}
+
+static void mt_dump_arange64(const struct maple_tree *mt, void *entry,
+ unsigned long min, unsigned long max, unsigned int depth,
+ enum mt_dump_format format)
+{
+ struct maple_arange_64 *node = &mte_to_node(entry)->ma64;
+ bool leaf = mte_is_leaf(entry);
+ unsigned long first = min;
+ int i;
+
+ pr_cont(" contents: ");
+ for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) {
+ switch (format) {
+ case mt_dump_hex:
+ pr_cont("%lx ", node->gap[i]);
+ break;
+ default:
+ case mt_dump_dec:
+ pr_cont("%lu ", node->gap[i]);
+ }
+ }
+ pr_cont("| %02X %02X| ", node->meta.end, node->meta.gap);
+ for (i = 0; i < MAPLE_ARANGE64_SLOTS - 1; i++) {
+ switch (format) {
+ case mt_dump_hex:
+ pr_cont("%p %lX ", node->slot[i], node->pivot[i]);
+ break;
+ default:
+ case mt_dump_dec:
+ pr_cont("%p %lu ", node->slot[i], node->pivot[i]);
+ }
+ }
+ pr_cont("%p\n", node->slot[i]);
+ for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) {
+ unsigned long last = max;
+
+ if (i < (MAPLE_ARANGE64_SLOTS - 1))
+ last = node->pivot[i];
+ else if (!node->slot[i])
+ break;
+ if (last == 0 && i > 0)
+ break;
+ if (leaf)
+ mt_dump_entry(mt_slot(mt, node->slot, i),
+ first, last, depth + 1, format);
+ else if (node->slot[i])
+ mt_dump_node(mt, mt_slot(mt, node->slot, i),
+ first, last, depth + 1, format);
+
+ if (last == max)
+ break;
+ if (last > max) {
+ pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n",
+ node, last, max, i);
+ break;
+ }
+ first = last + 1;
+ }
+}
+
+static void mt_dump_node(const struct maple_tree *mt, void *entry,
+ unsigned long min, unsigned long max, unsigned int depth,
+ enum mt_dump_format format)
+{
+ struct maple_node *node = mte_to_node(entry);
+ unsigned int type = mte_node_type(entry);
+ unsigned int i;
+
+ mt_dump_range(min, max, depth, format);
+
+ pr_cont("node %p depth %d type %d parent %p", node, depth, type,
+ node ? node->parent : NULL);
+ switch (type) {
+ case maple_dense:
+ pr_cont("\n");
+ for (i = 0; i < MAPLE_NODE_SLOTS; i++) {
+ if (min + i > max)
+ pr_cont("OUT OF RANGE: ");
+ mt_dump_entry(mt_slot(mt, node->slot, i),
+ min + i, min + i, depth, format);
+ }
+ break;
+ case maple_leaf_64:
+ case maple_range_64:
+ mt_dump_range64(mt, entry, min, max, depth, format);
+ break;
+ case maple_arange_64:
+ mt_dump_arange64(mt, entry, min, max, depth, format);
+ break;
+
+ default:
+ pr_cont(" UNKNOWN TYPE\n");
+ }
+}
+
+void mt_dump(const struct maple_tree *mt, enum mt_dump_format format)
+{
+ void *entry = rcu_dereference_check(mt->ma_root, mt_locked(mt));
+
+ pr_info("maple_tree(%p) flags %X, height %u root %p\n",
+ mt, mt->ma_flags, mt_height(mt), entry);
+ if (!xa_is_node(entry))
+ mt_dump_entry(entry, 0, 0, 0, format);
+ else if (entry)
+ mt_dump_node(mt, entry, 0, mt_node_max(entry), 0, format);
+}
+EXPORT_SYMBOL_GPL(mt_dump);
+
+/*
+ * Calculate the maximum gap in a node and check if that's what is reported in
+ * the parent (unless root).
+ */
+static void mas_validate_gaps(struct ma_state *mas)
+{
+ struct maple_enode *mte = mas->node;
+ struct maple_node *p_mn, *node = mte_to_node(mte);
+ enum maple_type mt = mte_node_type(mas->node);
+ unsigned long gap = 0, max_gap = 0;
+ unsigned long p_end, p_start = mas->min;
+ unsigned char p_slot, offset;
+ unsigned long *gaps = NULL;
+ unsigned long *pivots = ma_pivots(node, mt);
+ unsigned int i;
+
+ if (ma_is_dense(mt)) {
+ for (i = 0; i < mt_slot_count(mte); i++) {
+ if (mas_get_slot(mas, i)) {
+ if (gap > max_gap)
+ max_gap = gap;
+ gap = 0;
+ continue;
+ }
+ gap++;
+ }
+ goto counted;
+ }
+
+ gaps = ma_gaps(node, mt);
+ for (i = 0; i < mt_slot_count(mte); i++) {
+ p_end = mas_safe_pivot(mas, pivots, i, mt);
+
+ if (!gaps) {
+ if (!mas_get_slot(mas, i))
+ gap = p_end - p_start + 1;
+ } else {
+ void *entry = mas_get_slot(mas, i);
+
+ gap = gaps[i];
+ MT_BUG_ON(mas->tree, !entry);
+
+ if (gap > p_end - p_start + 1) {
+ pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n",
+ mas_mn(mas), i, gap, p_end, p_start,
+ p_end - p_start + 1);
+ MT_BUG_ON(mas->tree, gap > p_end - p_start + 1);
+ }
+ }
+
+ if (gap > max_gap)
+ max_gap = gap;
+
+ p_start = p_end + 1;
+ if (p_end >= mas->max)
+ break;
+ }
+
+counted:
+ if (mt == maple_arange_64) {
+ offset = ma_meta_gap(node, mt);
+ if (offset > i) {
+ pr_err("gap offset %p[%u] is invalid\n", node, offset);
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ if (gaps[offset] != max_gap) {
+ pr_err("gap %p[%u] is not the largest gap %lu\n",
+ node, offset, max_gap);
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ MT_BUG_ON(mas->tree, !gaps);
+ for (i++ ; i < mt_slot_count(mte); i++) {
+ if (gaps[i] != 0) {
+ pr_err("gap %p[%u] beyond node limit != 0\n",
+ node, i);
+ MT_BUG_ON(mas->tree, 1);
+ }
+ }
+ }
+
+ if (mte_is_root(mte))
+ return;
+
+ p_slot = mte_parent_slot(mas->node);
+ p_mn = mte_parent(mte);
+ MT_BUG_ON(mas->tree, max_gap > mas->max);
+ if (ma_gaps(p_mn, mas_parent_type(mas, mte))[p_slot] != max_gap) {
+ pr_err("gap %p[%u] != %lu\n", p_mn, p_slot, max_gap);
+ mt_dump(mas->tree, mt_dump_hex);
+ MT_BUG_ON(mas->tree, 1);
+ }
+}
+
+static void mas_validate_parent_slot(struct ma_state *mas)
+{
+ struct maple_node *parent;
+ struct maple_enode *node;
+ enum maple_type p_type;
+ unsigned char p_slot;
+ void __rcu **slots;
+ int i;
+
+ if (mte_is_root(mas->node))
+ return;
+
+ p_slot = mte_parent_slot(mas->node);
+ p_type = mas_parent_type(mas, mas->node);
+ parent = mte_parent(mas->node);
+ slots = ma_slots(parent, p_type);
+ MT_BUG_ON(mas->tree, mas_mn(mas) == parent);
+
+ /* Check prev/next parent slot for duplicate node entry */
+
+ for (i = 0; i < mt_slots[p_type]; i++) {
+ node = mas_slot(mas, slots, i);
+ if (i == p_slot) {
+ if (node != mas->node)
+ pr_err("parent %p[%u] does not have %p\n",
+ parent, i, mas_mn(mas));
+ MT_BUG_ON(mas->tree, node != mas->node);
+ } else if (node == mas->node) {
+ pr_err("Invalid child %p at parent %p[%u] p_slot %u\n",
+ mas_mn(mas), parent, i, p_slot);
+ MT_BUG_ON(mas->tree, node == mas->node);
+ }
+ }
+}
+
+static void mas_validate_child_slot(struct ma_state *mas)
+{
+ enum maple_type type = mte_node_type(mas->node);
+ void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
+ unsigned long *pivots = ma_pivots(mte_to_node(mas->node), type);
+ struct maple_enode *child;
+ unsigned char i;
+
+ if (mte_is_leaf(mas->node))
+ return;
+
+ for (i = 0; i < mt_slots[type]; i++) {
+ child = mas_slot(mas, slots, i);
+
+ if (!child) {
+ pr_err("Non-leaf node lacks child at %p[%u]\n",
+ mas_mn(mas), i);
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ if (mte_parent_slot(child) != i) {
+ pr_err("Slot error at %p[%u]: child %p has pslot %u\n",
+ mas_mn(mas), i, mte_to_node(child),
+ mte_parent_slot(child));
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ if (mte_parent(child) != mte_to_node(mas->node)) {
+ pr_err("child %p has parent %p not %p\n",
+ mte_to_node(child), mte_parent(child),
+ mte_to_node(mas->node));
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ if (i < mt_pivots[type] && pivots[i] == mas->max)
+ break;
+ }
+}
+
+/*
+ * Validate all pivots are within mas->min and mas->max, check metadata ends
+ * where the maximum ends and ensure there is no slots or pivots set outside of
+ * the end of the data.
+ */
+static void mas_validate_limits(struct ma_state *mas)
+{
+ int i;
+ unsigned long prev_piv = 0;
+ enum maple_type type = mte_node_type(mas->node);
+ void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
+ unsigned long *pivots = ma_pivots(mas_mn(mas), type);
+
+ for (i = 0; i < mt_slots[type]; i++) {
+ unsigned long piv;
+
+ piv = mas_safe_pivot(mas, pivots, i, type);
+
+ if (!piv && (i != 0)) {
+ pr_err("Missing node limit pivot at %p[%u]",
+ mas_mn(mas), i);
+ MAS_WARN_ON(mas, 1);
+ }
+
+ if (prev_piv > piv) {
+ pr_err("%p[%u] piv %lu < prev_piv %lu\n",
+ mas_mn(mas), i, piv, prev_piv);
+ MAS_WARN_ON(mas, piv < prev_piv);
+ }
+
+ if (piv < mas->min) {
+ pr_err("%p[%u] %lu < %lu\n", mas_mn(mas), i,
+ piv, mas->min);
+ MAS_WARN_ON(mas, piv < mas->min);
+ }
+ if (piv > mas->max) {
+ pr_err("%p[%u] %lu > %lu\n", mas_mn(mas), i,
+ piv, mas->max);
+ MAS_WARN_ON(mas, piv > mas->max);
+ }
+ prev_piv = piv;
+ if (piv == mas->max)
+ break;
+ }
+
+ if (mas_data_end(mas) != i) {
+ pr_err("node%p: data_end %u != the last slot offset %u\n",
+ mas_mn(mas), mas_data_end(mas), i);
+ MT_BUG_ON(mas->tree, 1);
+ }
+
+ for (i += 1; i < mt_slots[type]; i++) {
+ void *entry = mas_slot(mas, slots, i);
+
+ if (entry && (i != mt_slots[type] - 1)) {
+ pr_err("%p[%u] should not have entry %p\n", mas_mn(mas),
+ i, entry);
+ MT_BUG_ON(mas->tree, entry != NULL);
+ }
+
+ if (i < mt_pivots[type]) {
+ unsigned long piv = pivots[i];
+
+ if (!piv)
+ continue;
+
+ pr_err("%p[%u] should not have piv %lu\n",
+ mas_mn(mas), i, piv);
+ MAS_WARN_ON(mas, i < mt_pivots[type] - 1);
+ }
+ }
+}
+
+static void mt_validate_nulls(struct maple_tree *mt)
+{
+ void *entry, *last = (void *)1;
+ unsigned char offset = 0;
+ void __rcu **slots;
+ MA_STATE(mas, mt, 0, 0);
+
+ mas_start(&mas);
+ if (mas_is_none(&mas) || (mas.node == MAS_ROOT))
+ return;
+
+ while (!mte_is_leaf(mas.node))
+ mas_descend(&mas);
+
+ slots = ma_slots(mte_to_node(mas.node), mte_node_type(mas.node));
+ do {
+ entry = mas_slot(&mas, slots, offset);
+ if (!last && !entry) {
+ pr_err("Sequential nulls end at %p[%u]\n",
+ mas_mn(&mas), offset);
+ }
+ MT_BUG_ON(mt, !last && !entry);
+ last = entry;
+ if (offset == mas_data_end(&mas)) {
+ mas_next_node(&mas, mas_mn(&mas), ULONG_MAX);
+ if (mas_is_none(&mas))
+ return;
+ offset = 0;
+ slots = ma_slots(mte_to_node(mas.node),
+ mte_node_type(mas.node));
+ } else {
+ offset++;
+ }
+
+ } while (!mas_is_none(&mas));
+}
+
+/*
+ * validate a maple tree by checking:
+ * 1. The limits (pivots are within mas->min to mas->max)
+ * 2. The gap is correctly set in the parents
+ */
+void mt_validate(struct maple_tree *mt)
+{
+ unsigned char end;
+
+ MA_STATE(mas, mt, 0, 0);
+ rcu_read_lock();
+ mas_start(&mas);
+ if (!mas_searchable(&mas))
+ goto done;
+
+ while (!mte_is_leaf(mas.node))
+ mas_descend(&mas);
+
+ while (!mas_is_none(&mas)) {
+ MAS_WARN_ON(&mas, mte_dead_node(mas.node));
+ end = mas_data_end(&mas);
+ if (MAS_WARN_ON(&mas, (end < mt_min_slot_count(mas.node)) &&
+ (mas.max != ULONG_MAX))) {
+ pr_err("Invalid size %u of %p\n", end, mas_mn(&mas));
+ }
+
+ mas_validate_parent_slot(&mas);
+ mas_validate_limits(&mas);
+ mas_validate_child_slot(&mas);
+ if (mt_is_alloc(mt))
+ mas_validate_gaps(&mas);
+ mas_dfs_postorder(&mas, ULONG_MAX);
+ }
+ mt_validate_nulls(mt);
+done:
+ rcu_read_unlock();
+
+}
+EXPORT_SYMBOL_GPL(mt_validate);
+
+void mas_dump(const struct ma_state *mas)
+{
+ pr_err("MAS: tree=%p enode=%p ", mas->tree, mas->node);
+ if (mas_is_none(mas))
+ pr_err("(MAS_NONE) ");
+ else if (mas_is_ptr(mas))
+ pr_err("(MAS_ROOT) ");
+ else if (mas_is_start(mas))
+ pr_err("(MAS_START) ");
+ else if (mas_is_paused(mas))
+ pr_err("(MAS_PAUSED) ");
+
+ pr_err("[%u] index=%lx last=%lx\n", mas->offset, mas->index, mas->last);
+ pr_err(" min=%lx max=%lx alloc=%p, depth=%u, flags=%x\n",
+ mas->min, mas->max, mas->alloc, mas->depth, mas->mas_flags);
+ if (mas->index > mas->last)
+ pr_err("Check index & last\n");
+}
+EXPORT_SYMBOL_GPL(mas_dump);
+
+void mas_wr_dump(const struct ma_wr_state *wr_mas)
+{
+ pr_err("WR_MAS: node=%p r_min=%lx r_max=%lx\n",
+ wr_mas->node, wr_mas->r_min, wr_mas->r_max);
+ pr_err(" type=%u off_end=%u, node_end=%u, end_piv=%lx\n",
+ wr_mas->type, wr_mas->offset_end, wr_mas->node_end,
+ wr_mas->end_piv);
+}
+EXPORT_SYMBOL_GPL(mas_wr_dump);
+
+#endif /* CONFIG_DEBUG_MAPLE_TREE */