Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 472 insertions, 0 deletions

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
new file mode 100644
index 000000000..eae67015c
--- /dev/null
+++ b/include/linux/radix-tree.h
@@ -0,0 +1,472 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2001 Momchil Velikov
+ * Portions Copyright (C) 2001 Christoph Hellwig
+ * Copyright (C) 2006 Nick Piggin
+ * Copyright (C) 2012 Konstantin Khlebnikov
+ */
+#ifndef _LINUX_RADIX_TREE_H
+#define _LINUX_RADIX_TREE_H
+
+#include <linux/bitops.h>
+#include <linux/gfp_types.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/math.h>
+#include <linux/percpu.h>
+#include <linux/preempt.h>
+#include <linux/rcupdate.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/xarray.h>
+#include <linux/local_lock.h>
+
+/* Keep unconverted code working */
+#define radix_tree_root		xarray
+#define radix_tree_node		xa_node
+
+struct radix_tree_preload {
+	local_lock_t lock;
+	unsigned nr;
+	/* nodes->parent points to next preallocated node */
+	struct radix_tree_node *nodes;
+};
+DECLARE_PER_CPU(struct radix_tree_preload, radix_tree_preloads);
+
+/*
+ * The bottom two bits of the slot determine how the remaining bits in the
+ * slot are interpreted:
+ *
+ * 00 - data pointer
+ * 10 - internal entry
+ * x1 - value entry
+ *
+ * The internal entry may be a pointer to the next level in the tree, a
+ * sibling entry, or an indicator that the entry in this slot has been moved
+ * to another location in the tree and the lookup should be restarted.  While
+ * NULL fits the 'data pointer' pattern, it means that there is no entry in
+ * the tree for this index (no matter what level of the tree it is found at).
+ * This means that storing a NULL entry in the tree is the same as deleting
+ * the entry from the tree.
+ */
+#define RADIX_TREE_ENTRY_MASK		3UL
+#define RADIX_TREE_INTERNAL_NODE	2UL
+
+static inline bool radix_tree_is_internal_node(void *ptr)
+{
+	return ((unsigned long)ptr & RADIX_TREE_ENTRY_MASK) ==
+				RADIX_TREE_INTERNAL_NODE;
+}
+
+/*** radix-tree API starts here ***/
+
+#define RADIX_TREE_MAP_SHIFT	XA_CHUNK_SHIFT
+#define RADIX_TREE_MAP_SIZE	(1UL << RADIX_TREE_MAP_SHIFT)
+#define RADIX_TREE_MAP_MASK	(RADIX_TREE_MAP_SIZE-1)
+
+#define RADIX_TREE_MAX_TAGS	XA_MAX_MARKS
+#define RADIX_TREE_TAG_LONGS	XA_MARK_LONGS
+
+#define RADIX_TREE_INDEX_BITS  (8 /* CHAR_BIT */ * sizeof(unsigned long))
+#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
+					  RADIX_TREE_MAP_SHIFT))
+
+/* The IDR tag is stored in the low bits of xa_flags */
+#define ROOT_IS_IDR	((__force gfp_t)4)
+/* The top bits of xa_flags are used to store the root tags */
+#define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT)
+
+#define RADIX_TREE_INIT(name, mask)	XARRAY_INIT(name, mask)
+
+#define RADIX_TREE(name, mask) \
+	struct radix_tree_root name = RADIX_TREE_INIT(name, mask)
+
+#define INIT_RADIX_TREE(root, mask) xa_init_flags(root, mask)
+
+static inline bool radix_tree_empty(const struct radix_tree_root *root)
+{
+	return root->xa_head == NULL;
+}
+
+/**
+ * struct radix_tree_iter - radix tree iterator state
+ *
+ * @index:	index of current slot
+ * @next_index:	one beyond the last index for this chunk
+ * @tags:	bit-mask for tag-iterating
+ * @node:	node that contains current slot
+ *
+ * This radix tree iterator works in terms of "chunks" of slots.  A chunk is a
+ * subinterval of slots contained within one radix tree leaf node.  It is
+ * described by a pointer to its first slot and a struct radix_tree_iter
+ * which holds the chunk's position in the tree and its size.  For tagged
+ * iteration radix_tree_iter also holds the slots' bit-mask for one chosen
+ * radix tree tag.
+ */
+struct radix_tree_iter {
+	unsigned long	index;
+	unsigned long	next_index;
+	unsigned long	tags;
+	struct radix_tree_node *node;
+};
+
+/**
+ * Radix-tree synchronization
+ *
+ * The radix-tree API requires that users provide all synchronisation (with
+ * specific exceptions, noted below).
+ *
+ * Synchronization of access to the data items being stored in the tree, and
+ * management of their lifetimes must be completely managed by API users.
+ *
+ * For API usage, in general,
+ * - any function _modifying_ the tree or tags (inserting or deleting
+ *   items, setting or clearing tags) must exclude other modifications, and
+ *   exclude any functions reading the tree.
+ * - any function _reading_ the tree or tags (looking up items or tags,
+ *   gang lookups) must exclude modifications to the tree, but may occur
+ *   concurrently with other readers.
+ *
+ * The notable exceptions to this rule are the following functions:
+ * __radix_tree_lookup
+ * radix_tree_lookup
+ * radix_tree_lookup_slot
+ * radix_tree_tag_get
+ * radix_tree_gang_lookup
+ * radix_tree_gang_lookup_tag
+ * radix_tree_gang_lookup_tag_slot
+ * radix_tree_tagged
+ *
+ * The first 7 functions are able to be called locklessly, using RCU. The
+ * caller must ensure calls to these functions are made within rcu_read_lock()
+ * regions. Other readers (lock-free or otherwise) and modifications may be
+ * running concurrently.
+ *
+ * It is still required that the caller manage the synchronization and lifetimes
+ * of the items. So if RCU lock-free lookups are used, typically this would mean
+ * that the items have their own locks, or are amenable to lock-free access; and
+ * that the items are freed by RCU (or only freed after having been deleted from
+ * the radix tree *and* a synchronize_rcu() grace period).
+ *
+ * (Note, rcu_assign_pointer and rcu_dereference are not needed to control
+ * access to data items when inserting into or looking up from the radix tree)
+ *
+ * Note that the value returned by radix_tree_tag_get() may not be relied upon
+ * if only the RCU read lock is held.  Functions to set/clear tags and to
+ * delete nodes running concurrently with it may affect its result such that
+ * two consecutive reads in the same locked section may return different
+ * values.  If reliability is required, modification functions must also be
+ * excluded from concurrency.
+ *
+ * radix_tree_tagged is able to be called without locking or RCU.
+ */
+
+/**
+ * radix_tree_deref_slot - dereference a slot
+ * @slot: slot pointer, returned by radix_tree_lookup_slot
+ *
+ * For use with radix_tree_lookup_slot().  Caller must hold tree at least read
+ * locked across slot lookup and dereference. Not required if write lock is
+ * held (ie. items cannot be concurrently inserted).
+ *
+ * radix_tree_deref_retry must be used to confirm validity of the pointer if
+ * only the read lock is held.
+ *
+ * Return: entry stored in that slot.
+ */
+static inline void *radix_tree_deref_slot(void __rcu **slot)
+{
+	return rcu_dereference(*slot);
+}
+
+/**
+ * radix_tree_deref_slot_protected - dereference a slot with tree lock held
+ * @slot: slot pointer, returned by radix_tree_lookup_slot
+ *
+ * Similar to radix_tree_deref_slot.  The caller does not hold the RCU read
+ * lock but it must hold the tree lock to prevent parallel updates.
+ *
+ * Return: entry stored in that slot.
+ */
+static inline void *radix_tree_deref_slot_protected(void __rcu **slot,
+							spinlock_t *treelock)
+{
+	return rcu_dereference_protected(*slot, lockdep_is_held(treelock));
+}
+
+/**
+ * radix_tree_deref_retry	- check radix_tree_deref_slot
+ * @arg:	pointer returned by radix_tree_deref_slot
+ * Returns:	0 if retry is not required, otherwise retry is required
+ *
+ * radix_tree_deref_retry must be used with radix_tree_deref_slot.
+ */
+static inline int radix_tree_deref_retry(void *arg)
+{
+	return unlikely(radix_tree_is_internal_node(arg));
+}
+
+/**
+ * radix_tree_exception	- radix_tree_deref_slot returned either exception?
+ * @arg:	value returned by radix_tree_deref_slot
+ * Returns:	0 if well-aligned pointer, non-0 if either kind of exception.
+ */
+static inline int radix_tree_exception(void *arg)
+{
+	return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK);
+}
+
+int radix_tree_insert(struct radix_tree_root *, unsigned long index,
+			void *);
+void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index,
+			  struct radix_tree_node **nodep, void __rcu ***slotp);
+void *radix_tree_lookup(const struct radix_tree_root *, unsigned long);
+void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *,
+					unsigned long index);
+void __radix_tree_replace(struct radix_tree_root *, struct radix_tree_node *,
+			  void __rcu **slot, void *entry);
+void radix_tree_iter_replace(struct radix_tree_root *,
+		const struct radix_tree_iter *, void __rcu **slot, void *entry);
+void radix_tree_replace_slot(struct radix_tree_root *,
+			     void __rcu **slot, void *entry);
+void radix_tree_iter_delete(struct radix_tree_root *,
+			struct radix_tree_iter *iter, void __rcu **slot);
+void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *);
+void *radix_tree_delete(struct radix_tree_root *, unsigned long);
+unsigned int radix_tree_gang_lookup(const struct radix_tree_root *,
+			void **results, unsigned long first_index,
+			unsigned int max_items);
+int radix_tree_preload(gfp_t gfp_mask);
+int radix_tree_maybe_preload(gfp_t gfp_mask);
+void radix_tree_init(void);
+void *radix_tree_tag_set(struct radix_tree_root *,
+			unsigned long index, unsigned int tag);
+void *radix_tree_tag_clear(struct radix_tree_root *,
+			unsigned long index, unsigned int tag);
+int radix_tree_tag_get(const struct radix_tree_root *,
+			unsigned long index, unsigned int tag);
+void radix_tree_iter_tag_clear(struct radix_tree_root *,
+		const struct radix_tree_iter *iter, unsigned int tag);
+unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *,
+		void **results, unsigned long first_index,
+		unsigned int max_items, unsigned int tag);
+unsigned int radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *,
+		void __rcu ***results, unsigned long first_index,
+		unsigned int max_items, unsigned int tag);
+int radix_tree_tagged(const struct radix_tree_root *, unsigned int tag);
+
+static inline void radix_tree_preload_end(void)
+{
+	local_unlock(&radix_tree_preloads.lock);
+}
+
+void __rcu **idr_get_free(struct radix_tree_root *root,
+			      struct radix_tree_iter *iter, gfp_t gfp,
+			      unsigned long max);
+
+enum {
+	RADIX_TREE_ITER_TAG_MASK = 0x0f,	/* tag index in lower nybble */
+	RADIX_TREE_ITER_TAGGED   = 0x10,	/* lookup tagged slots */
+	RADIX_TREE_ITER_CONTIG   = 0x20,	/* stop at first hole */
+};
+
+/**
+ * radix_tree_iter_init - initialize radix tree iterator
+ *
+ * @iter:	pointer to iterator state
+ * @start:	iteration starting index
+ * Returns:	NULL
+ */
+static __always_inline void __rcu **
+radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start)
+{
+	/*
+	 * Leave iter->tags uninitialized. radix_tree_next_chunk() will fill it
+	 * in the case of a successful tagged chunk lookup.  If the lookup was
+	 * unsuccessful or non-tagged then nobody cares about ->tags.
+	 *
+	 * Set index to zero to bypass next_index overflow protection.
+	 * See the comment in radix_tree_next_chunk() for details.
+	 */
+	iter->index = 0;
+	iter->next_index = start;
+	return NULL;
+}
+
+/**
+ * radix_tree_next_chunk - find next chunk of slots for iteration
+ *
+ * @root:	radix tree root
+ * @iter:	iterator state
+ * @flags:	RADIX_TREE_ITER_* flags and tag index
+ * Returns:	pointer to chunk first slot, or NULL if there no more left
+ *
+ * This function looks up the next chunk in the radix tree starting from
+ * @iter->next_index.  It returns a pointer to the chunk's first slot.
+ * Also it fills @iter with data about chunk: position in the tree (index),
+ * its end (next_index), and constructs a bit mask for tagged iterating (tags).
+ */
+void __rcu **radix_tree_next_chunk(const struct radix_tree_root *,
+			     struct radix_tree_iter *iter, unsigned flags);
+
+/**
+ * radix_tree_iter_lookup - look up an index in the radix tree
+ * @root: radix tree root
+ * @iter: iterator state
+ * @index: key to look up
+ *
+ * If @index is present in the radix tree, this function returns the slot
+ * containing it and updates @iter to describe the entry.  If @index is not
+ * present, it returns NULL.
+ */
+static inline void __rcu **
+radix_tree_iter_lookup(const struct radix_tree_root *root,
+			struct radix_tree_iter *iter, unsigned long index)
+{
+	radix_tree_iter_init(iter, index);
+	return radix_tree_next_chunk(root, iter, RADIX_TREE_ITER_CONTIG);
+}
+
+/**
+ * radix_tree_iter_retry - retry this chunk of the iteration
+ * @iter:	iterator state
+ *
+ * If we iterate over a tree protected only by the RCU lock, a race
+ * against deletion or creation may result in seeing a slot for which
+ * radix_tree_deref_retry() returns true.  If so, call this function
+ * and continue the iteration.
+ */
+static inline __must_check
+void __rcu **radix_tree_iter_retry(struct radix_tree_iter *iter)
+{
+	iter->next_index = iter->index;
+	iter->tags = 0;
+	return NULL;
+}
+
+static inline unsigned long
+__radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots)
+{
+	return iter->index + slots;
+}
+
+/**
+ * radix_tree_iter_resume - resume iterating when the chunk may be invalid
+ * @slot: pointer to current slot
+ * @iter: iterator state
+ * Returns: New slot pointer
+ *
+ * If the iterator needs to release then reacquire a lock, the chunk may
+ * have been invalidated by an insertion or deletion.  Call this function
+ * before releasing the lock to continue the iteration from the next index.
+ */
+void __rcu **__must_check radix_tree_iter_resume(void __rcu **slot,
+					struct radix_tree_iter *iter);
+
+/**
+ * radix_tree_chunk_size - get current chunk size
+ *
+ * @iter:	pointer to radix tree iterator
+ * Returns:	current chunk size
+ */
+static __always_inline long
+radix_tree_chunk_size(struct radix_tree_iter *iter)
+{
+	return iter->next_index - iter->index;
+}
+
+/**
+ * radix_tree_next_slot - find next slot in chunk
+ *
+ * @slot:	pointer to current slot
+ * @iter:	pointer to iterator state
+ * @flags:	RADIX_TREE_ITER_*, should be constant
+ * Returns:	pointer to next slot, or NULL if there no more left
+ *
+ * This function updates @iter->index in the case of a successful lookup.
+ * For tagged lookup it also eats @iter->tags.
+ *
+ * There are several cases where 'slot' can be passed in as NULL to this
+ * function.  These cases result from the use of radix_tree_iter_resume() or
+ * radix_tree_iter_retry().  In these cases we don't end up dereferencing
+ * 'slot' because either:
+ * a) we are doing tagged iteration and iter->tags has been set to 0, or
+ * b) we are doing non-tagged iteration, and iter->index and iter->next_index
+ *    have been set up so that radix_tree_chunk_size() returns 1 or 0.
+ */
+static __always_inline void __rcu **radix_tree_next_slot(void __rcu **slot,
+				struct radix_tree_iter *iter, unsigned flags)
+{
+	if (flags & RADIX_TREE_ITER_TAGGED) {
+		iter->tags >>= 1;
+		if (unlikely(!iter->tags))
+			return NULL;
+		if (likely(iter->tags & 1ul)) {
+			iter->index = __radix_tree_iter_add(iter, 1);
+			slot++;
+			goto found;
+		}
+		if (!(flags & RADIX_TREE_ITER_CONTIG)) {
+			unsigned offset = __ffs(iter->tags);
+
+			iter->tags >>= offset++;
+			iter->index = __radix_tree_iter_add(iter, offset);
+			slot += offset;
+			goto found;
+		}
+	} else {
+		long count = radix_tree_chunk_size(iter);
+
+		while (--count > 0) {
+			slot++;
+			iter->index = __radix_tree_iter_add(iter, 1);
+
+			if (likely(*slot))
+				goto found;
+			if (flags & RADIX_TREE_ITER_CONTIG) {
+				/* forbid switching to the next chunk */
+				iter->next_index = 0;
+				break;
+			}
+		}
+	}
+	return NULL;
+
+ found:
+	return slot;
+}
+
+/**
+ * radix_tree_for_each_slot - iterate over non-empty slots
+ *
+ * @slot:	the void** variable for pointer to slot
+ * @root:	the struct radix_tree_root pointer
+ * @iter:	the struct radix_tree_iter pointer
+ * @start:	iteration starting index
+ *
+ * @slot points to radix tree slot, @iter->index contains its index.
+ */
+#define radix_tree_for_each_slot(slot, root, iter, start)		\
+	for (slot = radix_tree_iter_init(iter, start) ;			\
+	     slot || (slot = radix_tree_next_chunk(root, iter, 0)) ;	\
+	     slot = radix_tree_next_slot(slot, iter, 0))
+
+/**
+ * radix_tree_for_each_tagged - iterate over tagged slots
+ *
+ * @slot:	the void** variable for pointer to slot
+ * @root:	the struct radix_tree_root pointer
+ * @iter:	the struct radix_tree_iter pointer
+ * @start:	iteration starting index
+ * @tag:	tag index
+ *
+ * @slot points to radix tree slot, @iter->index contains its index.
+ */
+#define radix_tree_for_each_tagged(slot, root, iter, start, tag)	\
+	for (slot = radix_tree_iter_init(iter, start) ;			\
+	     slot || (slot = radix_tree_next_chunk(root, iter,		\
+			      RADIX_TREE_ITER_TAGGED | tag)) ;		\
+	     slot = radix_tree_next_slot(slot, iter,			\
+				RADIX_TREE_ITER_TAGGED | tag))
+
+#endif /* _LINUX_RADIX_TREE_H */