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-rw-r--r--kernel/bpf/hashtab.c2601
1 files changed, 2601 insertions, 0 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
new file mode 100644
index 0000000000..5b9146fa82
--- /dev/null
+++ b/kernel/bpf/hashtab.c
@@ -0,0 +1,2601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ */
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/jhash.h>
+#include <linux/filter.h>
+#include <linux/rculist_nulls.h>
+#include <linux/random.h>
+#include <uapi/linux/btf.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/btf_ids.h>
+#include "percpu_freelist.h"
+#include "bpf_lru_list.h"
+#include "map_in_map.h"
+#include <linux/bpf_mem_alloc.h>
+
+#define HTAB_CREATE_FLAG_MASK \
+ (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
+ BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
+
+#define BATCH_OPS(_name) \
+ .map_lookup_batch = \
+ _name##_map_lookup_batch, \
+ .map_lookup_and_delete_batch = \
+ _name##_map_lookup_and_delete_batch, \
+ .map_update_batch = \
+ generic_map_update_batch, \
+ .map_delete_batch = \
+ generic_map_delete_batch
+
+/*
+ * The bucket lock has two protection scopes:
+ *
+ * 1) Serializing concurrent operations from BPF programs on different
+ * CPUs
+ *
+ * 2) Serializing concurrent operations from BPF programs and sys_bpf()
+ *
+ * BPF programs can execute in any context including perf, kprobes and
+ * tracing. As there are almost no limits where perf, kprobes and tracing
+ * can be invoked from the lock operations need to be protected against
+ * deadlocks. Deadlocks can be caused by recursion and by an invocation in
+ * the lock held section when functions which acquire this lock are invoked
+ * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
+ * variable bpf_prog_active, which prevents BPF programs attached to perf
+ * events, kprobes and tracing to be invoked before the prior invocation
+ * from one of these contexts completed. sys_bpf() uses the same mechanism
+ * by pinning the task to the current CPU and incrementing the recursion
+ * protection across the map operation.
+ *
+ * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
+ * operations like memory allocations (even with GFP_ATOMIC) from atomic
+ * contexts. This is required because even with GFP_ATOMIC the memory
+ * allocator calls into code paths which acquire locks with long held lock
+ * sections. To ensure the deterministic behaviour these locks are regular
+ * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
+ * true atomic contexts on an RT kernel are the low level hardware
+ * handling, scheduling, low level interrupt handling, NMIs etc. None of
+ * these contexts should ever do memory allocations.
+ *
+ * As regular device interrupt handlers and soft interrupts are forced into
+ * thread context, the existing code which does
+ * spin_lock*(); alloc(GFP_ATOMIC); spin_unlock*();
+ * just works.
+ *
+ * In theory the BPF locks could be converted to regular spinlocks as well,
+ * but the bucket locks and percpu_freelist locks can be taken from
+ * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
+ * atomic contexts even on RT. Before the introduction of bpf_mem_alloc,
+ * it is only safe to use raw spinlock for preallocated hash map on a RT kernel,
+ * because there is no memory allocation within the lock held sections. However
+ * after hash map was fully converted to use bpf_mem_alloc, there will be
+ * non-synchronous memory allocation for non-preallocated hash map, so it is
+ * safe to always use raw spinlock for bucket lock.
+ */
+struct bucket {
+ struct hlist_nulls_head head;
+ raw_spinlock_t raw_lock;
+};
+
+#define HASHTAB_MAP_LOCK_COUNT 8
+#define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
+
+struct bpf_htab {
+ struct bpf_map map;
+ struct bpf_mem_alloc ma;
+ struct bpf_mem_alloc pcpu_ma;
+ struct bucket *buckets;
+ void *elems;
+ union {
+ struct pcpu_freelist freelist;
+ struct bpf_lru lru;
+ };
+ struct htab_elem *__percpu *extra_elems;
+ /* number of elements in non-preallocated hashtable are kept
+ * in either pcount or count
+ */
+ struct percpu_counter pcount;
+ atomic_t count;
+ bool use_percpu_counter;
+ u32 n_buckets; /* number of hash buckets */
+ u32 elem_size; /* size of each element in bytes */
+ u32 hashrnd;
+ struct lock_class_key lockdep_key;
+ int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
+};
+
+/* each htab element is struct htab_elem + key + value */
+struct htab_elem {
+ union {
+ struct hlist_nulls_node hash_node;
+ struct {
+ void *padding;
+ union {
+ struct pcpu_freelist_node fnode;
+ struct htab_elem *batch_flink;
+ };
+ };
+ };
+ union {
+ /* pointer to per-cpu pointer */
+ void *ptr_to_pptr;
+ struct bpf_lru_node lru_node;
+ };
+ u32 hash;
+ char key[] __aligned(8);
+};
+
+static inline bool htab_is_prealloc(const struct bpf_htab *htab)
+{
+ return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
+}
+
+static void htab_init_buckets(struct bpf_htab *htab)
+{
+ unsigned int i;
+
+ for (i = 0; i < htab->n_buckets; i++) {
+ INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
+ raw_spin_lock_init(&htab->buckets[i].raw_lock);
+ lockdep_set_class(&htab->buckets[i].raw_lock,
+ &htab->lockdep_key);
+ cond_resched();
+ }
+}
+
+static inline int htab_lock_bucket(const struct bpf_htab *htab,
+ struct bucket *b, u32 hash,
+ unsigned long *pflags)
+{
+ unsigned long flags;
+
+ hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
+
+ preempt_disable();
+ local_irq_save(flags);
+ if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
+ __this_cpu_dec(*(htab->map_locked[hash]));
+ local_irq_restore(flags);
+ preempt_enable();
+ return -EBUSY;
+ }
+
+ raw_spin_lock(&b->raw_lock);
+ *pflags = flags;
+
+ return 0;
+}
+
+static inline void htab_unlock_bucket(const struct bpf_htab *htab,
+ struct bucket *b, u32 hash,
+ unsigned long flags)
+{
+ hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
+ raw_spin_unlock(&b->raw_lock);
+ __this_cpu_dec(*(htab->map_locked[hash]));
+ local_irq_restore(flags);
+ preempt_enable();
+}
+
+static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
+
+static bool htab_is_lru(const struct bpf_htab *htab)
+{
+ return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
+ htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
+}
+
+static bool htab_is_percpu(const struct bpf_htab *htab)
+{
+ return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
+}
+
+static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
+ void __percpu *pptr)
+{
+ *(void __percpu **)(l->key + key_size) = pptr;
+}
+
+static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
+{
+ return *(void __percpu **)(l->key + key_size);
+}
+
+static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
+{
+ return *(void **)(l->key + roundup(map->key_size, 8));
+}
+
+static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
+{
+ return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
+}
+
+static bool htab_has_extra_elems(struct bpf_htab *htab)
+{
+ return !htab_is_percpu(htab) && !htab_is_lru(htab);
+}
+
+static void htab_free_prealloced_timers(struct bpf_htab *htab)
+{
+ u32 num_entries = htab->map.max_entries;
+ int i;
+
+ if (!btf_record_has_field(htab->map.record, BPF_TIMER))
+ return;
+ if (htab_has_extra_elems(htab))
+ num_entries += num_possible_cpus();
+
+ for (i = 0; i < num_entries; i++) {
+ struct htab_elem *elem;
+
+ elem = get_htab_elem(htab, i);
+ bpf_obj_free_timer(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
+ cond_resched();
+ }
+}
+
+static void htab_free_prealloced_fields(struct bpf_htab *htab)
+{
+ u32 num_entries = htab->map.max_entries;
+ int i;
+
+ if (IS_ERR_OR_NULL(htab->map.record))
+ return;
+ if (htab_has_extra_elems(htab))
+ num_entries += num_possible_cpus();
+ for (i = 0; i < num_entries; i++) {
+ struct htab_elem *elem;
+
+ elem = get_htab_elem(htab, i);
+ if (htab_is_percpu(htab)) {
+ void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
+ cond_resched();
+ }
+ } else {
+ bpf_obj_free_fields(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
+ cond_resched();
+ }
+ cond_resched();
+ }
+}
+
+static void htab_free_elems(struct bpf_htab *htab)
+{
+ int i;
+
+ if (!htab_is_percpu(htab))
+ goto free_elems;
+
+ for (i = 0; i < htab->map.max_entries; i++) {
+ void __percpu *pptr;
+
+ pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
+ htab->map.key_size);
+ free_percpu(pptr);
+ cond_resched();
+ }
+free_elems:
+ bpf_map_area_free(htab->elems);
+}
+
+/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
+ * (bucket_lock). If both locks need to be acquired together, the lock
+ * order is always lru_lock -> bucket_lock and this only happens in
+ * bpf_lru_list.c logic. For example, certain code path of
+ * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
+ * will acquire lru_lock first followed by acquiring bucket_lock.
+ *
+ * In hashtab.c, to avoid deadlock, lock acquisition of
+ * bucket_lock followed by lru_lock is not allowed. In such cases,
+ * bucket_lock needs to be released first before acquiring lru_lock.
+ */
+static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
+ u32 hash)
+{
+ struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
+ struct htab_elem *l;
+
+ if (node) {
+ bpf_map_inc_elem_count(&htab->map);
+ l = container_of(node, struct htab_elem, lru_node);
+ memcpy(l->key, key, htab->map.key_size);
+ return l;
+ }
+
+ return NULL;
+}
+
+static int prealloc_init(struct bpf_htab *htab)
+{
+ u32 num_entries = htab->map.max_entries;
+ int err = -ENOMEM, i;
+
+ if (htab_has_extra_elems(htab))
+ num_entries += num_possible_cpus();
+
+ htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
+ htab->map.numa_node);
+ if (!htab->elems)
+ return -ENOMEM;
+
+ if (!htab_is_percpu(htab))
+ goto skip_percpu_elems;
+
+ for (i = 0; i < num_entries; i++) {
+ u32 size = round_up(htab->map.value_size, 8);
+ void __percpu *pptr;
+
+ pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
+ GFP_USER | __GFP_NOWARN);
+ if (!pptr)
+ goto free_elems;
+ htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
+ pptr);
+ cond_resched();
+ }
+
+skip_percpu_elems:
+ if (htab_is_lru(htab))
+ err = bpf_lru_init(&htab->lru,
+ htab->map.map_flags & BPF_F_NO_COMMON_LRU,
+ offsetof(struct htab_elem, hash) -
+ offsetof(struct htab_elem, lru_node),
+ htab_lru_map_delete_node,
+ htab);
+ else
+ err = pcpu_freelist_init(&htab->freelist);
+
+ if (err)
+ goto free_elems;
+
+ if (htab_is_lru(htab))
+ bpf_lru_populate(&htab->lru, htab->elems,
+ offsetof(struct htab_elem, lru_node),
+ htab->elem_size, num_entries);
+ else
+ pcpu_freelist_populate(&htab->freelist,
+ htab->elems + offsetof(struct htab_elem, fnode),
+ htab->elem_size, num_entries);
+
+ return 0;
+
+free_elems:
+ htab_free_elems(htab);
+ return err;
+}
+
+static void prealloc_destroy(struct bpf_htab *htab)
+{
+ htab_free_elems(htab);
+
+ if (htab_is_lru(htab))
+ bpf_lru_destroy(&htab->lru);
+ else
+ pcpu_freelist_destroy(&htab->freelist);
+}
+
+static int alloc_extra_elems(struct bpf_htab *htab)
+{
+ struct htab_elem *__percpu *pptr, *l_new;
+ struct pcpu_freelist_node *l;
+ int cpu;
+
+ pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
+ GFP_USER | __GFP_NOWARN);
+ if (!pptr)
+ return -ENOMEM;
+
+ for_each_possible_cpu(cpu) {
+ l = pcpu_freelist_pop(&htab->freelist);
+ /* pop will succeed, since prealloc_init()
+ * preallocated extra num_possible_cpus elements
+ */
+ l_new = container_of(l, struct htab_elem, fnode);
+ *per_cpu_ptr(pptr, cpu) = l_new;
+ }
+ htab->extra_elems = pptr;
+ return 0;
+}
+
+/* Called from syscall */
+static int htab_map_alloc_check(union bpf_attr *attr)
+{
+ bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+ bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
+ attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+ /* percpu_lru means each cpu has its own LRU list.
+ * it is different from BPF_MAP_TYPE_PERCPU_HASH where
+ * the map's value itself is percpu. percpu_lru has
+ * nothing to do with the map's value.
+ */
+ bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
+ bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
+ bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
+ int numa_node = bpf_map_attr_numa_node(attr);
+
+ BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
+ offsetof(struct htab_elem, hash_node.pprev));
+
+ if (zero_seed && !capable(CAP_SYS_ADMIN))
+ /* Guard against local DoS, and discourage production use. */
+ return -EPERM;
+
+ if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
+ !bpf_map_flags_access_ok(attr->map_flags))
+ return -EINVAL;
+
+ if (!lru && percpu_lru)
+ return -EINVAL;
+
+ if (lru && !prealloc)
+ return -ENOTSUPP;
+
+ if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
+ return -EINVAL;
+
+ /* check sanity of attributes.
+ * value_size == 0 may be allowed in the future to use map as a set
+ */
+ if (attr->max_entries == 0 || attr->key_size == 0 ||
+ attr->value_size == 0)
+ return -EINVAL;
+
+ if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
+ sizeof(struct htab_elem))
+ /* if key_size + value_size is bigger, the user space won't be
+ * able to access the elements via bpf syscall. This check
+ * also makes sure that the elem_size doesn't overflow and it's
+ * kmalloc-able later in htab_map_update_elem()
+ */
+ return -E2BIG;
+
+ return 0;
+}
+
+static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
+{
+ bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+ bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
+ attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+ /* percpu_lru means each cpu has its own LRU list.
+ * it is different from BPF_MAP_TYPE_PERCPU_HASH where
+ * the map's value itself is percpu. percpu_lru has
+ * nothing to do with the map's value.
+ */
+ bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
+ bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
+ struct bpf_htab *htab;
+ int err, i;
+
+ htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
+ if (!htab)
+ return ERR_PTR(-ENOMEM);
+
+ lockdep_register_key(&htab->lockdep_key);
+
+ bpf_map_init_from_attr(&htab->map, attr);
+
+ if (percpu_lru) {
+ /* ensure each CPU's lru list has >=1 elements.
+ * since we are at it, make each lru list has the same
+ * number of elements.
+ */
+ htab->map.max_entries = roundup(attr->max_entries,
+ num_possible_cpus());
+ if (htab->map.max_entries < attr->max_entries)
+ htab->map.max_entries = rounddown(attr->max_entries,
+ num_possible_cpus());
+ }
+
+ /* hash table size must be power of 2 */
+ htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
+
+ htab->elem_size = sizeof(struct htab_elem) +
+ round_up(htab->map.key_size, 8);
+ if (percpu)
+ htab->elem_size += sizeof(void *);
+ else
+ htab->elem_size += round_up(htab->map.value_size, 8);
+
+ err = -E2BIG;
+ /* prevent zero size kmalloc and check for u32 overflow */
+ if (htab->n_buckets == 0 ||
+ htab->n_buckets > U32_MAX / sizeof(struct bucket))
+ goto free_htab;
+
+ err = bpf_map_init_elem_count(&htab->map);
+ if (err)
+ goto free_htab;
+
+ err = -ENOMEM;
+ htab->buckets = bpf_map_area_alloc(htab->n_buckets *
+ sizeof(struct bucket),
+ htab->map.numa_node);
+ if (!htab->buckets)
+ goto free_elem_count;
+
+ for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
+ htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
+ sizeof(int),
+ sizeof(int),
+ GFP_USER);
+ if (!htab->map_locked[i])
+ goto free_map_locked;
+ }
+
+ if (htab->map.map_flags & BPF_F_ZERO_SEED)
+ htab->hashrnd = 0;
+ else
+ htab->hashrnd = get_random_u32();
+
+ htab_init_buckets(htab);
+
+/* compute_batch_value() computes batch value as num_online_cpus() * 2
+ * and __percpu_counter_compare() needs
+ * htab->max_entries - cur_number_of_elems to be more than batch * num_online_cpus()
+ * for percpu_counter to be faster than atomic_t. In practice the average bpf
+ * hash map size is 10k, which means that a system with 64 cpus will fill
+ * hashmap to 20% of 10k before percpu_counter becomes ineffective. Therefore
+ * define our own batch count as 32 then 10k hash map can be filled up to 80%:
+ * 10k - 8k > 32 _batch_ * 64 _cpus_
+ * and __percpu_counter_compare() will still be fast. At that point hash map
+ * collisions will dominate its performance anyway. Assume that hash map filled
+ * to 50+% isn't going to be O(1) and use the following formula to choose
+ * between percpu_counter and atomic_t.
+ */
+#define PERCPU_COUNTER_BATCH 32
+ if (attr->max_entries / 2 > num_online_cpus() * PERCPU_COUNTER_BATCH)
+ htab->use_percpu_counter = true;
+
+ if (htab->use_percpu_counter) {
+ err = percpu_counter_init(&htab->pcount, 0, GFP_KERNEL);
+ if (err)
+ goto free_map_locked;
+ }
+
+ if (prealloc) {
+ err = prealloc_init(htab);
+ if (err)
+ goto free_map_locked;
+
+ if (!percpu && !lru) {
+ /* lru itself can remove the least used element, so
+ * there is no need for an extra elem during map_update.
+ */
+ err = alloc_extra_elems(htab);
+ if (err)
+ goto free_prealloc;
+ }
+ } else {
+ err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false);
+ if (err)
+ goto free_map_locked;
+ if (percpu) {
+ err = bpf_mem_alloc_init(&htab->pcpu_ma,
+ round_up(htab->map.value_size, 8), true);
+ if (err)
+ goto free_map_locked;
+ }
+ }
+
+ return &htab->map;
+
+free_prealloc:
+ prealloc_destroy(htab);
+free_map_locked:
+ if (htab->use_percpu_counter)
+ percpu_counter_destroy(&htab->pcount);
+ for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
+ free_percpu(htab->map_locked[i]);
+ bpf_map_area_free(htab->buckets);
+ bpf_mem_alloc_destroy(&htab->pcpu_ma);
+ bpf_mem_alloc_destroy(&htab->ma);
+free_elem_count:
+ bpf_map_free_elem_count(&htab->map);
+free_htab:
+ lockdep_unregister_key(&htab->lockdep_key);
+ bpf_map_area_free(htab);
+ return ERR_PTR(err);
+}
+
+static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
+{
+ if (likely(key_len % 4 == 0))
+ return jhash2(key, key_len / 4, hashrnd);
+ return jhash(key, key_len, hashrnd);
+}
+
+static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
+{
+ return &htab->buckets[hash & (htab->n_buckets - 1)];
+}
+
+static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
+{
+ return &__select_bucket(htab, hash)->head;
+}
+
+/* this lookup function can only be called with bucket lock taken */
+static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
+ void *key, u32 key_size)
+{
+ struct hlist_nulls_node *n;
+ struct htab_elem *l;
+
+ hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+ if (l->hash == hash && !memcmp(&l->key, key, key_size))
+ return l;
+
+ return NULL;
+}
+
+/* can be called without bucket lock. it will repeat the loop in
+ * the unlikely event when elements moved from one bucket into another
+ * while link list is being walked
+ */
+static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
+ u32 hash, void *key,
+ u32 key_size, u32 n_buckets)
+{
+ struct hlist_nulls_node *n;
+ struct htab_elem *l;
+
+again:
+ hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+ if (l->hash == hash && !memcmp(&l->key, key, key_size))
+ return l;
+
+ if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
+ goto again;
+
+ return NULL;
+}
+
+/* Called from syscall or from eBPF program directly, so
+ * arguments have to match bpf_map_lookup_elem() exactly.
+ * The return value is adjusted by BPF instructions
+ * in htab_map_gen_lookup().
+ */
+static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ struct htab_elem *l;
+ u32 hash, key_size;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ head = select_bucket(htab, hash);
+
+ l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
+
+ return l;
+}
+
+static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+ if (l)
+ return l->key + round_up(map->key_size, 8);
+
+ return NULL;
+}
+
+/* inline bpf_map_lookup_elem() call.
+ * Instead of:
+ * bpf_prog
+ * bpf_map_lookup_elem
+ * map->ops->map_lookup_elem
+ * htab_map_lookup_elem
+ * __htab_map_lookup_elem
+ * do:
+ * bpf_prog
+ * __htab_map_lookup_elem
+ */
+static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+{
+ struct bpf_insn *insn = insn_buf;
+ const int ret = BPF_REG_0;
+
+ BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+ (void *(*)(struct bpf_map *map, void *key))NULL));
+ *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+ *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
+ *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+ offsetof(struct htab_elem, key) +
+ round_up(map->key_size, 8));
+ return insn - insn_buf;
+}
+
+static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
+ void *key, const bool mark)
+{
+ struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+ if (l) {
+ if (mark)
+ bpf_lru_node_set_ref(&l->lru_node);
+ return l->key + round_up(map->key_size, 8);
+ }
+
+ return NULL;
+}
+
+static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ return __htab_lru_map_lookup_elem(map, key, true);
+}
+
+static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
+{
+ return __htab_lru_map_lookup_elem(map, key, false);
+}
+
+static int htab_lru_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf)
+{
+ struct bpf_insn *insn = insn_buf;
+ const int ret = BPF_REG_0;
+ const int ref_reg = BPF_REG_1;
+
+ BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+ (void *(*)(struct bpf_map *map, void *key))NULL));
+ *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+ *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
+ *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
+ offsetof(struct htab_elem, lru_node) +
+ offsetof(struct bpf_lru_node, ref));
+ *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
+ *insn++ = BPF_ST_MEM(BPF_B, ret,
+ offsetof(struct htab_elem, lru_node) +
+ offsetof(struct bpf_lru_node, ref),
+ 1);
+ *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+ offsetof(struct htab_elem, key) +
+ round_up(map->key_size, 8));
+ return insn - insn_buf;
+}
+
+static void check_and_free_fields(struct bpf_htab *htab,
+ struct htab_elem *elem)
+{
+ if (htab_is_percpu(htab)) {
+ void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
+ } else {
+ void *map_value = elem->key + round_up(htab->map.key_size, 8);
+
+ bpf_obj_free_fields(htab->map.record, map_value);
+ }
+}
+
+/* It is called from the bpf_lru_list when the LRU needs to delete
+ * older elements from the htab.
+ */
+static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
+{
+ struct bpf_htab *htab = arg;
+ struct htab_elem *l = NULL, *tgt_l;
+ struct hlist_nulls_head *head;
+ struct hlist_nulls_node *n;
+ unsigned long flags;
+ struct bucket *b;
+ int ret;
+
+ tgt_l = container_of(node, struct htab_elem, lru_node);
+ b = __select_bucket(htab, tgt_l->hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
+ if (ret)
+ return false;
+
+ hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+ if (l == tgt_l) {
+ hlist_nulls_del_rcu(&l->hash_node);
+ check_and_free_fields(htab, l);
+ bpf_map_dec_elem_count(&htab->map);
+ break;
+ }
+
+ htab_unlock_bucket(htab, b, tgt_l->hash, flags);
+
+ return l == tgt_l;
+}
+
+/* Called from syscall */
+static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ struct htab_elem *l, *next_l;
+ u32 hash, key_size;
+ int i = 0;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ key_size = map->key_size;
+
+ if (!key)
+ goto find_first_elem;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ head = select_bucket(htab, hash);
+
+ /* lookup the key */
+ l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
+
+ if (!l)
+ goto find_first_elem;
+
+ /* key was found, get next key in the same bucket */
+ next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
+ struct htab_elem, hash_node);
+
+ if (next_l) {
+ /* if next elem in this hash list is non-zero, just return it */
+ memcpy(next_key, next_l->key, key_size);
+ return 0;
+ }
+
+ /* no more elements in this hash list, go to the next bucket */
+ i = hash & (htab->n_buckets - 1);
+ i++;
+
+find_first_elem:
+ /* iterate over buckets */
+ for (; i < htab->n_buckets; i++) {
+ head = select_bucket(htab, i);
+
+ /* pick first element in the bucket */
+ next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
+ struct htab_elem, hash_node);
+ if (next_l) {
+ /* if it's not empty, just return it */
+ memcpy(next_key, next_l->key, key_size);
+ return 0;
+ }
+ }
+
+ /* iterated over all buckets and all elements */
+ return -ENOENT;
+}
+
+static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
+{
+ check_and_free_fields(htab, l);
+ if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
+ bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr);
+ bpf_mem_cache_free(&htab->ma, l);
+}
+
+static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
+{
+ struct bpf_map *map = &htab->map;
+ void *ptr;
+
+ if (map->ops->map_fd_put_ptr) {
+ ptr = fd_htab_map_get_ptr(map, l);
+ map->ops->map_fd_put_ptr(map, ptr, true);
+ }
+}
+
+static bool is_map_full(struct bpf_htab *htab)
+{
+ if (htab->use_percpu_counter)
+ return __percpu_counter_compare(&htab->pcount, htab->map.max_entries,
+ PERCPU_COUNTER_BATCH) >= 0;
+ return atomic_read(&htab->count) >= htab->map.max_entries;
+}
+
+static void inc_elem_count(struct bpf_htab *htab)
+{
+ bpf_map_inc_elem_count(&htab->map);
+
+ if (htab->use_percpu_counter)
+ percpu_counter_add_batch(&htab->pcount, 1, PERCPU_COUNTER_BATCH);
+ else
+ atomic_inc(&htab->count);
+}
+
+static void dec_elem_count(struct bpf_htab *htab)
+{
+ bpf_map_dec_elem_count(&htab->map);
+
+ if (htab->use_percpu_counter)
+ percpu_counter_add_batch(&htab->pcount, -1, PERCPU_COUNTER_BATCH);
+ else
+ atomic_dec(&htab->count);
+}
+
+
+static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+{
+ htab_put_fd_value(htab, l);
+
+ if (htab_is_prealloc(htab)) {
+ bpf_map_dec_elem_count(&htab->map);
+ check_and_free_fields(htab, l);
+ __pcpu_freelist_push(&htab->freelist, &l->fnode);
+ } else {
+ dec_elem_count(htab);
+ htab_elem_free(htab, l);
+ }
+}
+
+static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
+ void *value, bool onallcpus)
+{
+ if (!onallcpus) {
+ /* copy true value_size bytes */
+ copy_map_value(&htab->map, this_cpu_ptr(pptr), value);
+ } else {
+ u32 size = round_up(htab->map.value_size, 8);
+ int off = 0, cpu;
+
+ for_each_possible_cpu(cpu) {
+ copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value + off);
+ off += size;
+ }
+ }
+}
+
+static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
+ void *value, bool onallcpus)
+{
+ /* When not setting the initial value on all cpus, zero-fill element
+ * values for other cpus. Otherwise, bpf program has no way to ensure
+ * known initial values for cpus other than current one
+ * (onallcpus=false always when coming from bpf prog).
+ */
+ if (!onallcpus) {
+ int current_cpu = raw_smp_processor_id();
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (cpu == current_cpu)
+ copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value);
+ else /* Since elem is preallocated, we cannot touch special fields */
+ zero_map_value(&htab->map, per_cpu_ptr(pptr, cpu));
+ }
+ } else {
+ pcpu_copy_value(htab, pptr, value, onallcpus);
+ }
+}
+
+static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
+{
+ return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
+ BITS_PER_LONG == 64;
+}
+
+static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
+ void *value, u32 key_size, u32 hash,
+ bool percpu, bool onallcpus,
+ struct htab_elem *old_elem)
+{
+ u32 size = htab->map.value_size;
+ bool prealloc = htab_is_prealloc(htab);
+ struct htab_elem *l_new, **pl_new;
+ void __percpu *pptr;
+
+ if (prealloc) {
+ if (old_elem) {
+ /* if we're updating the existing element,
+ * use per-cpu extra elems to avoid freelist_pop/push
+ */
+ pl_new = this_cpu_ptr(htab->extra_elems);
+ l_new = *pl_new;
+ htab_put_fd_value(htab, old_elem);
+ *pl_new = old_elem;
+ } else {
+ struct pcpu_freelist_node *l;
+
+ l = __pcpu_freelist_pop(&htab->freelist);
+ if (!l)
+ return ERR_PTR(-E2BIG);
+ l_new = container_of(l, struct htab_elem, fnode);
+ bpf_map_inc_elem_count(&htab->map);
+ }
+ } else {
+ if (is_map_full(htab))
+ if (!old_elem)
+ /* when map is full and update() is replacing
+ * old element, it's ok to allocate, since
+ * old element will be freed immediately.
+ * Otherwise return an error
+ */
+ return ERR_PTR(-E2BIG);
+ inc_elem_count(htab);
+ l_new = bpf_mem_cache_alloc(&htab->ma);
+ if (!l_new) {
+ l_new = ERR_PTR(-ENOMEM);
+ goto dec_count;
+ }
+ }
+
+ memcpy(l_new->key, key, key_size);
+ if (percpu) {
+ if (prealloc) {
+ pptr = htab_elem_get_ptr(l_new, key_size);
+ } else {
+ /* alloc_percpu zero-fills */
+ pptr = bpf_mem_cache_alloc(&htab->pcpu_ma);
+ if (!pptr) {
+ bpf_mem_cache_free(&htab->ma, l_new);
+ l_new = ERR_PTR(-ENOMEM);
+ goto dec_count;
+ }
+ l_new->ptr_to_pptr = pptr;
+ pptr = *(void **)pptr;
+ }
+
+ pcpu_init_value(htab, pptr, value, onallcpus);
+
+ if (!prealloc)
+ htab_elem_set_ptr(l_new, key_size, pptr);
+ } else if (fd_htab_map_needs_adjust(htab)) {
+ size = round_up(size, 8);
+ memcpy(l_new->key + round_up(key_size, 8), value, size);
+ } else {
+ copy_map_value(&htab->map,
+ l_new->key + round_up(key_size, 8),
+ value);
+ }
+
+ l_new->hash = hash;
+ return l_new;
+dec_count:
+ dec_elem_count(htab);
+ return l_new;
+}
+
+static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
+ u64 map_flags)
+{
+ if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
+ /* elem already exists */
+ return -EEXIST;
+
+ if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
+ /* elem doesn't exist, cannot update it */
+ return -ENOENT;
+
+ return 0;
+}
+
+/* Called from syscall or from eBPF program */
+static long htab_map_update_elem(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct htab_elem *l_new = NULL, *l_old;
+ struct hlist_nulls_head *head;
+ unsigned long flags;
+ struct bucket *b;
+ u32 key_size, hash;
+ int ret;
+
+ if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
+ /* unknown flags */
+ return -EINVAL;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ if (unlikely(map_flags & BPF_F_LOCK)) {
+ if (unlikely(!btf_record_has_field(map->record, BPF_SPIN_LOCK)))
+ return -EINVAL;
+ /* find an element without taking the bucket lock */
+ l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
+ htab->n_buckets);
+ ret = check_flags(htab, l_old, map_flags);
+ if (ret)
+ return ret;
+ if (l_old) {
+ /* grab the element lock and update value in place */
+ copy_map_value_locked(map,
+ l_old->key + round_up(key_size, 8),
+ value, false);
+ return 0;
+ }
+ /* fall through, grab the bucket lock and lookup again.
+ * 99.9% chance that the element won't be found,
+ * but second lookup under lock has to be done.
+ */
+ }
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ return ret;
+
+ l_old = lookup_elem_raw(head, hash, key, key_size);
+
+ ret = check_flags(htab, l_old, map_flags);
+ if (ret)
+ goto err;
+
+ if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
+ /* first lookup without the bucket lock didn't find the element,
+ * but second lookup with the bucket lock found it.
+ * This case is highly unlikely, but has to be dealt with:
+ * grab the element lock in addition to the bucket lock
+ * and update element in place
+ */
+ copy_map_value_locked(map,
+ l_old->key + round_up(key_size, 8),
+ value, false);
+ ret = 0;
+ goto err;
+ }
+
+ l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
+ l_old);
+ if (IS_ERR(l_new)) {
+ /* all pre-allocated elements are in use or memory exhausted */
+ ret = PTR_ERR(l_new);
+ goto err;
+ }
+
+ /* add new element to the head of the list, so that
+ * concurrent search will find it before old elem
+ */
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+ if (l_old) {
+ hlist_nulls_del_rcu(&l_old->hash_node);
+ if (!htab_is_prealloc(htab))
+ free_htab_elem(htab, l_old);
+ else
+ check_and_free_fields(htab, l_old);
+ }
+ ret = 0;
+err:
+ htab_unlock_bucket(htab, b, hash, flags);
+ return ret;
+}
+
+static void htab_lru_push_free(struct bpf_htab *htab, struct htab_elem *elem)
+{
+ check_and_free_fields(htab, elem);
+ bpf_map_dec_elem_count(&htab->map);
+ bpf_lru_push_free(&htab->lru, &elem->lru_node);
+}
+
+static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct htab_elem *l_new, *l_old = NULL;
+ struct hlist_nulls_head *head;
+ unsigned long flags;
+ struct bucket *b;
+ u32 key_size, hash;
+ int ret;
+
+ if (unlikely(map_flags > BPF_EXIST))
+ /* unknown flags */
+ return -EINVAL;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ /* For LRU, we need to alloc before taking bucket's
+ * spinlock because getting free nodes from LRU may need
+ * to remove older elements from htab and this removal
+ * operation will need a bucket lock.
+ */
+ l_new = prealloc_lru_pop(htab, key, hash);
+ if (!l_new)
+ return -ENOMEM;
+ copy_map_value(&htab->map,
+ l_new->key + round_up(map->key_size, 8), value);
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ goto err_lock_bucket;
+
+ l_old = lookup_elem_raw(head, hash, key, key_size);
+
+ ret = check_flags(htab, l_old, map_flags);
+ if (ret)
+ goto err;
+
+ /* add new element to the head of the list, so that
+ * concurrent search will find it before old elem
+ */
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+ if (l_old) {
+ bpf_lru_node_set_ref(&l_new->lru_node);
+ hlist_nulls_del_rcu(&l_old->hash_node);
+ }
+ ret = 0;
+
+err:
+ htab_unlock_bucket(htab, b, hash, flags);
+
+err_lock_bucket:
+ if (ret)
+ htab_lru_push_free(htab, l_new);
+ else if (l_old)
+ htab_lru_push_free(htab, l_old);
+
+ return ret;
+}
+
+static long __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 map_flags,
+ bool onallcpus)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct htab_elem *l_new = NULL, *l_old;
+ struct hlist_nulls_head *head;
+ unsigned long flags;
+ struct bucket *b;
+ u32 key_size, hash;
+ int ret;
+
+ if (unlikely(map_flags > BPF_EXIST))
+ /* unknown flags */
+ return -EINVAL;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ return ret;
+
+ l_old = lookup_elem_raw(head, hash, key, key_size);
+
+ ret = check_flags(htab, l_old, map_flags);
+ if (ret)
+ goto err;
+
+ if (l_old) {
+ /* per-cpu hash map can update value in-place */
+ pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
+ value, onallcpus);
+ } else {
+ l_new = alloc_htab_elem(htab, key, value, key_size,
+ hash, true, onallcpus, NULL);
+ if (IS_ERR(l_new)) {
+ ret = PTR_ERR(l_new);
+ goto err;
+ }
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+ }
+ ret = 0;
+err:
+ htab_unlock_bucket(htab, b, hash, flags);
+ return ret;
+}
+
+static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 map_flags,
+ bool onallcpus)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct htab_elem *l_new = NULL, *l_old;
+ struct hlist_nulls_head *head;
+ unsigned long flags;
+ struct bucket *b;
+ u32 key_size, hash;
+ int ret;
+
+ if (unlikely(map_flags > BPF_EXIST))
+ /* unknown flags */
+ return -EINVAL;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ /* For LRU, we need to alloc before taking bucket's
+ * spinlock because LRU's elem alloc may need
+ * to remove older elem from htab and this removal
+ * operation will need a bucket lock.
+ */
+ if (map_flags != BPF_EXIST) {
+ l_new = prealloc_lru_pop(htab, key, hash);
+ if (!l_new)
+ return -ENOMEM;
+ }
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ goto err_lock_bucket;
+
+ l_old = lookup_elem_raw(head, hash, key, key_size);
+
+ ret = check_flags(htab, l_old, map_flags);
+ if (ret)
+ goto err;
+
+ if (l_old) {
+ bpf_lru_node_set_ref(&l_old->lru_node);
+
+ /* per-cpu hash map can update value in-place */
+ pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
+ value, onallcpus);
+ } else {
+ pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
+ value, onallcpus);
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+ l_new = NULL;
+ }
+ ret = 0;
+err:
+ htab_unlock_bucket(htab, b, hash, flags);
+err_lock_bucket:
+ if (l_new) {
+ bpf_map_dec_elem_count(&htab->map);
+ bpf_lru_push_free(&htab->lru, &l_new->lru_node);
+ }
+ return ret;
+}
+
+static long htab_percpu_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 map_flags)
+{
+ return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
+}
+
+static long htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
+ void *value, u64 map_flags)
+{
+ return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
+ false);
+}
+
+/* Called from syscall or from eBPF program */
+static long htab_map_delete_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ struct bucket *b;
+ struct htab_elem *l;
+ unsigned long flags;
+ u32 hash, key_size;
+ int ret;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ return ret;
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+
+ if (l) {
+ hlist_nulls_del_rcu(&l->hash_node);
+ free_htab_elem(htab, l);
+ } else {
+ ret = -ENOENT;
+ }
+
+ htab_unlock_bucket(htab, b, hash, flags);
+ return ret;
+}
+
+static long htab_lru_map_delete_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ struct bucket *b;
+ struct htab_elem *l;
+ unsigned long flags;
+ u32 hash, key_size;
+ int ret;
+
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, hash, &flags);
+ if (ret)
+ return ret;
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+
+ if (l)
+ hlist_nulls_del_rcu(&l->hash_node);
+ else
+ ret = -ENOENT;
+
+ htab_unlock_bucket(htab, b, hash, flags);
+ if (l)
+ htab_lru_push_free(htab, l);
+ return ret;
+}
+
+static void delete_all_elements(struct bpf_htab *htab)
+{
+ int i;
+
+ /* It's called from a worker thread, so disable migration here,
+ * since bpf_mem_cache_free() relies on that.
+ */
+ migrate_disable();
+ for (i = 0; i < htab->n_buckets; i++) {
+ struct hlist_nulls_head *head = select_bucket(htab, i);
+ struct hlist_nulls_node *n;
+ struct htab_elem *l;
+
+ hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+ hlist_nulls_del_rcu(&l->hash_node);
+ htab_elem_free(htab, l);
+ }
+ }
+ migrate_enable();
+}
+
+static void htab_free_malloced_timers(struct bpf_htab *htab)
+{
+ int i;
+
+ rcu_read_lock();
+ for (i = 0; i < htab->n_buckets; i++) {
+ struct hlist_nulls_head *head = select_bucket(htab, i);
+ struct hlist_nulls_node *n;
+ struct htab_elem *l;
+
+ hlist_nulls_for_each_entry(l, n, head, hash_node) {
+ /* We only free timer on uref dropping to zero */
+ bpf_obj_free_timer(htab->map.record, l->key + round_up(htab->map.key_size, 8));
+ }
+ cond_resched_rcu();
+ }
+ rcu_read_unlock();
+}
+
+static void htab_map_free_timers(struct bpf_map *map)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+
+ /* We only free timer on uref dropping to zero */
+ if (!btf_record_has_field(htab->map.record, BPF_TIMER))
+ return;
+ if (!htab_is_prealloc(htab))
+ htab_free_malloced_timers(htab);
+ else
+ htab_free_prealloced_timers(htab);
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void htab_map_free(struct bpf_map *map)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ int i;
+
+ /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
+ * bpf_free_used_maps() is called after bpf prog is no longer executing.
+ * There is no need to synchronize_rcu() here to protect map elements.
+ */
+
+ /* htab no longer uses call_rcu() directly. bpf_mem_alloc does it
+ * underneath and is reponsible for waiting for callbacks to finish
+ * during bpf_mem_alloc_destroy().
+ */
+ if (!htab_is_prealloc(htab)) {
+ delete_all_elements(htab);
+ } else {
+ htab_free_prealloced_fields(htab);
+ prealloc_destroy(htab);
+ }
+
+ bpf_map_free_elem_count(map);
+ free_percpu(htab->extra_elems);
+ bpf_map_area_free(htab->buckets);
+ bpf_mem_alloc_destroy(&htab->pcpu_ma);
+ bpf_mem_alloc_destroy(&htab->ma);
+ if (htab->use_percpu_counter)
+ percpu_counter_destroy(&htab->pcount);
+ for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
+ free_percpu(htab->map_locked[i]);
+ lockdep_unregister_key(&htab->lockdep_key);
+ bpf_map_area_free(htab);
+}
+
+static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
+ struct seq_file *m)
+{
+ void *value;
+
+ rcu_read_lock();
+
+ value = htab_map_lookup_elem(map, key);
+ if (!value) {
+ rcu_read_unlock();
+ return;
+ }
+
+ btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+ seq_puts(m, ": ");
+ btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
+ seq_puts(m, "\n");
+
+ rcu_read_unlock();
+}
+
+static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, bool is_lru_map,
+ bool is_percpu, u64 flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ unsigned long bflags;
+ struct htab_elem *l;
+ u32 hash, key_size;
+ struct bucket *b;
+ int ret;
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, hash, &bflags);
+ if (ret)
+ return ret;
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+ if (!l) {
+ ret = -ENOENT;
+ } else {
+ if (is_percpu) {
+ u32 roundup_value_size = round_up(map->value_size, 8);
+ void __percpu *pptr;
+ int off = 0, cpu;
+
+ pptr = htab_elem_get_ptr(l, key_size);
+ for_each_possible_cpu(cpu) {
+ copy_map_value_long(&htab->map, value + off, per_cpu_ptr(pptr, cpu));
+ check_and_init_map_value(&htab->map, value + off);
+ off += roundup_value_size;
+ }
+ } else {
+ u32 roundup_key_size = round_up(map->key_size, 8);
+
+ if (flags & BPF_F_LOCK)
+ copy_map_value_locked(map, value, l->key +
+ roundup_key_size,
+ true);
+ else
+ copy_map_value(map, value, l->key +
+ roundup_key_size);
+ /* Zeroing special fields in the temp buffer */
+ check_and_init_map_value(map, value);
+ }
+
+ hlist_nulls_del_rcu(&l->hash_node);
+ if (!is_lru_map)
+ free_htab_elem(htab, l);
+ }
+
+ htab_unlock_bucket(htab, b, hash, bflags);
+
+ if (is_lru_map && l)
+ htab_lru_push_free(htab, l);
+
+ return ret;
+}
+
+static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
+ flags);
+}
+
+static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+ void *key, void *value,
+ u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
+ flags);
+}
+
+static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
+ flags);
+}
+
+static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+ void *key, void *value,
+ u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
+ flags);
+}
+
+static int
+__htab_map_lookup_and_delete_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr,
+ bool do_delete, bool is_lru_map,
+ bool is_percpu)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
+ void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
+ void __user *uvalues = u64_to_user_ptr(attr->batch.values);
+ void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
+ void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
+ u32 batch, max_count, size, bucket_size, map_id;
+ struct htab_elem *node_to_free = NULL;
+ u64 elem_map_flags, map_flags;
+ struct hlist_nulls_head *head;
+ struct hlist_nulls_node *n;
+ unsigned long flags = 0;
+ bool locked = false;
+ struct htab_elem *l;
+ struct bucket *b;
+ int ret = 0;
+
+ elem_map_flags = attr->batch.elem_flags;
+ if ((elem_map_flags & ~BPF_F_LOCK) ||
+ ((elem_map_flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
+ return -EINVAL;
+
+ map_flags = attr->batch.flags;
+ if (map_flags)
+ return -EINVAL;
+
+ max_count = attr->batch.count;
+ if (!max_count)
+ return 0;
+
+ if (put_user(0, &uattr->batch.count))
+ return -EFAULT;
+
+ batch = 0;
+ if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
+ return -EFAULT;
+
+ if (batch >= htab->n_buckets)
+ return -ENOENT;
+
+ key_size = htab->map.key_size;
+ roundup_key_size = round_up(htab->map.key_size, 8);
+ value_size = htab->map.value_size;
+ size = round_up(value_size, 8);
+ if (is_percpu)
+ value_size = size * num_possible_cpus();
+ total = 0;
+ /* while experimenting with hash tables with sizes ranging from 10 to
+ * 1000, it was observed that a bucket can have up to 5 entries.
+ */
+ bucket_size = 5;
+
+alloc:
+ /* We cannot do copy_from_user or copy_to_user inside
+ * the rcu_read_lock. Allocate enough space here.
+ */
+ keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
+ values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
+ if (!keys || !values) {
+ ret = -ENOMEM;
+ goto after_loop;
+ }
+
+again:
+ bpf_disable_instrumentation();
+ rcu_read_lock();
+again_nocopy:
+ dst_key = keys;
+ dst_val = values;
+ b = &htab->buckets[batch];
+ head = &b->head;
+ /* do not grab the lock unless need it (bucket_cnt > 0). */
+ if (locked) {
+ ret = htab_lock_bucket(htab, b, batch, &flags);
+ if (ret) {
+ rcu_read_unlock();
+ bpf_enable_instrumentation();
+ goto after_loop;
+ }
+ }
+
+ bucket_cnt = 0;
+ hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+ bucket_cnt++;
+
+ if (bucket_cnt && !locked) {
+ locked = true;
+ goto again_nocopy;
+ }
+
+ if (bucket_cnt > (max_count - total)) {
+ if (total == 0)
+ ret = -ENOSPC;
+ /* Note that since bucket_cnt > 0 here, it is implicit
+ * that the locked was grabbed, so release it.
+ */
+ htab_unlock_bucket(htab, b, batch, flags);
+ rcu_read_unlock();
+ bpf_enable_instrumentation();
+ goto after_loop;
+ }
+
+ if (bucket_cnt > bucket_size) {
+ bucket_size = bucket_cnt;
+ /* Note that since bucket_cnt > 0 here, it is implicit
+ * that the locked was grabbed, so release it.
+ */
+ htab_unlock_bucket(htab, b, batch, flags);
+ rcu_read_unlock();
+ bpf_enable_instrumentation();
+ kvfree(keys);
+ kvfree(values);
+ goto alloc;
+ }
+
+ /* Next block is only safe to run if you have grabbed the lock */
+ if (!locked)
+ goto next_batch;
+
+ hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+ memcpy(dst_key, l->key, key_size);
+
+ if (is_percpu) {
+ int off = 0, cpu;
+ void __percpu *pptr;
+
+ pptr = htab_elem_get_ptr(l, map->key_size);
+ for_each_possible_cpu(cpu) {
+ copy_map_value_long(&htab->map, dst_val + off, per_cpu_ptr(pptr, cpu));
+ check_and_init_map_value(&htab->map, dst_val + off);
+ off += size;
+ }
+ } else {
+ value = l->key + roundup_key_size;
+ if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
+ struct bpf_map **inner_map = value;
+
+ /* Actual value is the id of the inner map */
+ map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
+ value = &map_id;
+ }
+
+ if (elem_map_flags & BPF_F_LOCK)
+ copy_map_value_locked(map, dst_val, value,
+ true);
+ else
+ copy_map_value(map, dst_val, value);
+ /* Zeroing special fields in the temp buffer */
+ check_and_init_map_value(map, dst_val);
+ }
+ if (do_delete) {
+ hlist_nulls_del_rcu(&l->hash_node);
+
+ /* bpf_lru_push_free() will acquire lru_lock, which
+ * may cause deadlock. See comments in function
+ * prealloc_lru_pop(). Let us do bpf_lru_push_free()
+ * after releasing the bucket lock.
+ */
+ if (is_lru_map) {
+ l->batch_flink = node_to_free;
+ node_to_free = l;
+ } else {
+ free_htab_elem(htab, l);
+ }
+ }
+ dst_key += key_size;
+ dst_val += value_size;
+ }
+
+ htab_unlock_bucket(htab, b, batch, flags);
+ locked = false;
+
+ while (node_to_free) {
+ l = node_to_free;
+ node_to_free = node_to_free->batch_flink;
+ htab_lru_push_free(htab, l);
+ }
+
+next_batch:
+ /* If we are not copying data, we can go to next bucket and avoid
+ * unlocking the rcu.
+ */
+ if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
+ batch++;
+ goto again_nocopy;
+ }
+
+ rcu_read_unlock();
+ bpf_enable_instrumentation();
+ if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
+ key_size * bucket_cnt) ||
+ copy_to_user(uvalues + total * value_size, values,
+ value_size * bucket_cnt))) {
+ ret = -EFAULT;
+ goto after_loop;
+ }
+
+ total += bucket_cnt;
+ batch++;
+ if (batch >= htab->n_buckets) {
+ ret = -ENOENT;
+ goto after_loop;
+ }
+ goto again;
+
+after_loop:
+ if (ret == -EFAULT)
+ goto out;
+
+ /* copy # of entries and next batch */
+ ubatch = u64_to_user_ptr(attr->batch.out_batch);
+ if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
+ put_user(total, &uattr->batch.count))
+ ret = -EFAULT;
+
+out:
+ kvfree(keys);
+ kvfree(values);
+ return ret;
+}
+
+static int
+htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+ false, true);
+}
+
+static int
+htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+ false, true);
+}
+
+static int
+htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+ false, false);
+}
+
+static int
+htab_map_lookup_and_delete_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+ false, false);
+}
+
+static int
+htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+ true, true);
+}
+
+static int
+htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+ true, true);
+}
+
+static int
+htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+ true, false);
+}
+
+static int
+htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+ true, false);
+}
+
+struct bpf_iter_seq_hash_map_info {
+ struct bpf_map *map;
+ struct bpf_htab *htab;
+ void *percpu_value_buf; // non-zero means percpu hash
+ u32 bucket_id;
+ u32 skip_elems;
+};
+
+static struct htab_elem *
+bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
+ struct htab_elem *prev_elem)
+{
+ const struct bpf_htab *htab = info->htab;
+ u32 skip_elems = info->skip_elems;
+ u32 bucket_id = info->bucket_id;
+ struct hlist_nulls_head *head;
+ struct hlist_nulls_node *n;
+ struct htab_elem *elem;
+ struct bucket *b;
+ u32 i, count;
+
+ if (bucket_id >= htab->n_buckets)
+ return NULL;
+
+ /* try to find next elem in the same bucket */
+ if (prev_elem) {
+ /* no update/deletion on this bucket, prev_elem should be still valid
+ * and we won't skip elements.
+ */
+ n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
+ elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
+ if (elem)
+ return elem;
+
+ /* not found, unlock and go to the next bucket */
+ b = &htab->buckets[bucket_id++];
+ rcu_read_unlock();
+ skip_elems = 0;
+ }
+
+ for (i = bucket_id; i < htab->n_buckets; i++) {
+ b = &htab->buckets[i];
+ rcu_read_lock();
+
+ count = 0;
+ head = &b->head;
+ hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
+ if (count >= skip_elems) {
+ info->bucket_id = i;
+ info->skip_elems = count;
+ return elem;
+ }
+ count++;
+ }
+
+ rcu_read_unlock();
+ skip_elems = 0;
+ }
+
+ info->bucket_id = i;
+ info->skip_elems = 0;
+ return NULL;
+}
+
+static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct bpf_iter_seq_hash_map_info *info = seq->private;
+ struct htab_elem *elem;
+
+ elem = bpf_hash_map_seq_find_next(info, NULL);
+ if (!elem)
+ return NULL;
+
+ if (*pos == 0)
+ ++*pos;
+ return elem;
+}
+
+static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct bpf_iter_seq_hash_map_info *info = seq->private;
+
+ ++*pos;
+ ++info->skip_elems;
+ return bpf_hash_map_seq_find_next(info, v);
+}
+
+static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
+{
+ struct bpf_iter_seq_hash_map_info *info = seq->private;
+ u32 roundup_key_size, roundup_value_size;
+ struct bpf_iter__bpf_map_elem ctx = {};
+ struct bpf_map *map = info->map;
+ struct bpf_iter_meta meta;
+ int ret = 0, off = 0, cpu;
+ struct bpf_prog *prog;
+ void __percpu *pptr;
+
+ meta.seq = seq;
+ prog = bpf_iter_get_info(&meta, elem == NULL);
+ if (prog) {
+ ctx.meta = &meta;
+ ctx.map = info->map;
+ if (elem) {
+ roundup_key_size = round_up(map->key_size, 8);
+ ctx.key = elem->key;
+ if (!info->percpu_value_buf) {
+ ctx.value = elem->key + roundup_key_size;
+ } else {
+ roundup_value_size = round_up(map->value_size, 8);
+ pptr = htab_elem_get_ptr(elem, map->key_size);
+ for_each_possible_cpu(cpu) {
+ copy_map_value_long(map, info->percpu_value_buf + off,
+ per_cpu_ptr(pptr, cpu));
+ check_and_init_map_value(map, info->percpu_value_buf + off);
+ off += roundup_value_size;
+ }
+ ctx.value = info->percpu_value_buf;
+ }
+ }
+ ret = bpf_iter_run_prog(prog, &ctx);
+ }
+
+ return ret;
+}
+
+static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
+{
+ return __bpf_hash_map_seq_show(seq, v);
+}
+
+static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
+{
+ if (!v)
+ (void)__bpf_hash_map_seq_show(seq, NULL);
+ else
+ rcu_read_unlock();
+}
+
+static int bpf_iter_init_hash_map(void *priv_data,
+ struct bpf_iter_aux_info *aux)
+{
+ struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
+ struct bpf_map *map = aux->map;
+ void *value_buf;
+ u32 buf_size;
+
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+ map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+ buf_size = round_up(map->value_size, 8) * num_possible_cpus();
+ value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
+ if (!value_buf)
+ return -ENOMEM;
+
+ seq_info->percpu_value_buf = value_buf;
+ }
+
+ bpf_map_inc_with_uref(map);
+ seq_info->map = map;
+ seq_info->htab = container_of(map, struct bpf_htab, map);
+ return 0;
+}
+
+static void bpf_iter_fini_hash_map(void *priv_data)
+{
+ struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
+
+ bpf_map_put_with_uref(seq_info->map);
+ kfree(seq_info->percpu_value_buf);
+}
+
+static const struct seq_operations bpf_hash_map_seq_ops = {
+ .start = bpf_hash_map_seq_start,
+ .next = bpf_hash_map_seq_next,
+ .stop = bpf_hash_map_seq_stop,
+ .show = bpf_hash_map_seq_show,
+};
+
+static const struct bpf_iter_seq_info iter_seq_info = {
+ .seq_ops = &bpf_hash_map_seq_ops,
+ .init_seq_private = bpf_iter_init_hash_map,
+ .fini_seq_private = bpf_iter_fini_hash_map,
+ .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
+};
+
+static long bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn,
+ void *callback_ctx, u64 flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ struct hlist_nulls_node *n;
+ struct htab_elem *elem;
+ u32 roundup_key_size;
+ int i, num_elems = 0;
+ void __percpu *pptr;
+ struct bucket *b;
+ void *key, *val;
+ bool is_percpu;
+ u64 ret = 0;
+
+ if (flags != 0)
+ return -EINVAL;
+
+ is_percpu = htab_is_percpu(htab);
+
+ roundup_key_size = round_up(map->key_size, 8);
+ /* disable migration so percpu value prepared here will be the
+ * same as the one seen by the bpf program with bpf_map_lookup_elem().
+ */
+ if (is_percpu)
+ migrate_disable();
+ for (i = 0; i < htab->n_buckets; i++) {
+ b = &htab->buckets[i];
+ rcu_read_lock();
+ head = &b->head;
+ hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
+ key = elem->key;
+ if (is_percpu) {
+ /* current cpu value for percpu map */
+ pptr = htab_elem_get_ptr(elem, map->key_size);
+ val = this_cpu_ptr(pptr);
+ } else {
+ val = elem->key + roundup_key_size;
+ }
+ num_elems++;
+ ret = callback_fn((u64)(long)map, (u64)(long)key,
+ (u64)(long)val, (u64)(long)callback_ctx, 0);
+ /* return value: 0 - continue, 1 - stop and return */
+ if (ret) {
+ rcu_read_unlock();
+ goto out;
+ }
+ }
+ rcu_read_unlock();
+ }
+out:
+ if (is_percpu)
+ migrate_enable();
+ return num_elems;
+}
+
+static u64 htab_map_mem_usage(const struct bpf_map *map)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ u32 value_size = round_up(htab->map.value_size, 8);
+ bool prealloc = htab_is_prealloc(htab);
+ bool percpu = htab_is_percpu(htab);
+ bool lru = htab_is_lru(htab);
+ u64 num_entries;
+ u64 usage = sizeof(struct bpf_htab);
+
+ usage += sizeof(struct bucket) * htab->n_buckets;
+ usage += sizeof(int) * num_possible_cpus() * HASHTAB_MAP_LOCK_COUNT;
+ if (prealloc) {
+ num_entries = map->max_entries;
+ if (htab_has_extra_elems(htab))
+ num_entries += num_possible_cpus();
+
+ usage += htab->elem_size * num_entries;
+
+ if (percpu)
+ usage += value_size * num_possible_cpus() * num_entries;
+ else if (!lru)
+ usage += sizeof(struct htab_elem *) * num_possible_cpus();
+ } else {
+#define LLIST_NODE_SZ sizeof(struct llist_node)
+
+ num_entries = htab->use_percpu_counter ?
+ percpu_counter_sum(&htab->pcount) :
+ atomic_read(&htab->count);
+ usage += (htab->elem_size + LLIST_NODE_SZ) * num_entries;
+ if (percpu) {
+ usage += (LLIST_NODE_SZ + sizeof(void *)) * num_entries;
+ usage += value_size * num_possible_cpus() * num_entries;
+ }
+ }
+ return usage;
+}
+
+BTF_ID_LIST_SINGLE(htab_map_btf_ids, struct, bpf_htab)
+const struct bpf_map_ops htab_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = htab_map_alloc_check,
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_release_uref = htab_map_free_timers,
+ .map_lookup_elem = htab_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
+ .map_update_elem = htab_map_update_elem,
+ .map_delete_elem = htab_map_delete_elem,
+ .map_gen_lookup = htab_map_gen_lookup,
+ .map_seq_show_elem = htab_map_seq_show_elem,
+ .map_set_for_each_callback_args = map_set_for_each_callback_args,
+ .map_for_each_callback = bpf_for_each_hash_elem,
+ .map_mem_usage = htab_map_mem_usage,
+ BATCH_OPS(htab),
+ .map_btf_id = &htab_map_btf_ids[0],
+ .iter_seq_info = &iter_seq_info,
+};
+
+const struct bpf_map_ops htab_lru_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = htab_map_alloc_check,
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_release_uref = htab_map_free_timers,
+ .map_lookup_elem = htab_lru_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
+ .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
+ .map_update_elem = htab_lru_map_update_elem,
+ .map_delete_elem = htab_lru_map_delete_elem,
+ .map_gen_lookup = htab_lru_map_gen_lookup,
+ .map_seq_show_elem = htab_map_seq_show_elem,
+ .map_set_for_each_callback_args = map_set_for_each_callback_args,
+ .map_for_each_callback = bpf_for_each_hash_elem,
+ .map_mem_usage = htab_map_mem_usage,
+ BATCH_OPS(htab_lru),
+ .map_btf_id = &htab_map_btf_ids[0],
+ .iter_seq_info = &iter_seq_info,
+};
+
+/* Called from eBPF program */
+static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+ if (l)
+ return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
+ else
+ return NULL;
+}
+
+static void *htab_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
+{
+ struct htab_elem *l;
+
+ if (cpu >= nr_cpu_ids)
+ return NULL;
+
+ l = __htab_map_lookup_elem(map, key);
+ if (l)
+ return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
+ else
+ return NULL;
+}
+
+static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+ if (l) {
+ bpf_lru_node_set_ref(&l->lru_node);
+ return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
+ }
+
+ return NULL;
+}
+
+static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
+{
+ struct htab_elem *l;
+
+ if (cpu >= nr_cpu_ids)
+ return NULL;
+
+ l = __htab_map_lookup_elem(map, key);
+ if (l) {
+ bpf_lru_node_set_ref(&l->lru_node);
+ return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
+ }
+
+ return NULL;
+}
+
+int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
+{
+ struct htab_elem *l;
+ void __percpu *pptr;
+ int ret = -ENOENT;
+ int cpu, off = 0;
+ u32 size;
+
+ /* per_cpu areas are zero-filled and bpf programs can only
+ * access 'value_size' of them, so copying rounded areas
+ * will not leak any kernel data
+ */
+ size = round_up(map->value_size, 8);
+ rcu_read_lock();
+ l = __htab_map_lookup_elem(map, key);
+ if (!l)
+ goto out;
+ /* We do not mark LRU map element here in order to not mess up
+ * eviction heuristics when user space does a map walk.
+ */
+ pptr = htab_elem_get_ptr(l, map->key_size);
+ for_each_possible_cpu(cpu) {
+ copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
+ check_and_init_map_value(map, value + off);
+ off += size;
+ }
+ ret = 0;
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
+int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ int ret;
+
+ rcu_read_lock();
+ if (htab_is_lru(htab))
+ ret = __htab_lru_percpu_map_update_elem(map, key, value,
+ map_flags, true);
+ else
+ ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
+ true);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
+ struct seq_file *m)
+{
+ struct htab_elem *l;
+ void __percpu *pptr;
+ int cpu;
+
+ rcu_read_lock();
+
+ l = __htab_map_lookup_elem(map, key);
+ if (!l) {
+ rcu_read_unlock();
+ return;
+ }
+
+ btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+ seq_puts(m, ": {\n");
+ pptr = htab_elem_get_ptr(l, map->key_size);
+ for_each_possible_cpu(cpu) {
+ seq_printf(m, "\tcpu%d: ", cpu);
+ btf_type_seq_show(map->btf, map->btf_value_type_id,
+ per_cpu_ptr(pptr, cpu), m);
+ seq_puts(m, "\n");
+ }
+ seq_puts(m, "}\n");
+
+ rcu_read_unlock();
+}
+
+const struct bpf_map_ops htab_percpu_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = htab_map_alloc_check,
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_lookup_elem = htab_percpu_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
+ .map_update_elem = htab_percpu_map_update_elem,
+ .map_delete_elem = htab_map_delete_elem,
+ .map_lookup_percpu_elem = htab_percpu_map_lookup_percpu_elem,
+ .map_seq_show_elem = htab_percpu_map_seq_show_elem,
+ .map_set_for_each_callback_args = map_set_for_each_callback_args,
+ .map_for_each_callback = bpf_for_each_hash_elem,
+ .map_mem_usage = htab_map_mem_usage,
+ BATCH_OPS(htab_percpu),
+ .map_btf_id = &htab_map_btf_ids[0],
+ .iter_seq_info = &iter_seq_info,
+};
+
+const struct bpf_map_ops htab_lru_percpu_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = htab_map_alloc_check,
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
+ .map_update_elem = htab_lru_percpu_map_update_elem,
+ .map_delete_elem = htab_lru_map_delete_elem,
+ .map_lookup_percpu_elem = htab_lru_percpu_map_lookup_percpu_elem,
+ .map_seq_show_elem = htab_percpu_map_seq_show_elem,
+ .map_set_for_each_callback_args = map_set_for_each_callback_args,
+ .map_for_each_callback = bpf_for_each_hash_elem,
+ .map_mem_usage = htab_map_mem_usage,
+ BATCH_OPS(htab_lru_percpu),
+ .map_btf_id = &htab_map_btf_ids[0],
+ .iter_seq_info = &iter_seq_info,
+};
+
+static int fd_htab_map_alloc_check(union bpf_attr *attr)
+{
+ if (attr->value_size != sizeof(u32))
+ return -EINVAL;
+ return htab_map_alloc_check(attr);
+}
+
+static void fd_htab_map_free(struct bpf_map *map)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_node *n;
+ struct hlist_nulls_head *head;
+ struct htab_elem *l;
+ int i;
+
+ for (i = 0; i < htab->n_buckets; i++) {
+ head = select_bucket(htab, i);
+
+ hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+ void *ptr = fd_htab_map_get_ptr(map, l);
+
+ map->ops->map_fd_put_ptr(map, ptr, false);
+ }
+ }
+
+ htab_map_free(map);
+}
+
+/* only called from syscall */
+int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
+{
+ void **ptr;
+ int ret = 0;
+
+ if (!map->ops->map_fd_sys_lookup_elem)
+ return -ENOTSUPP;
+
+ rcu_read_lock();
+ ptr = htab_map_lookup_elem(map, key);
+ if (ptr)
+ *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
+ else
+ ret = -ENOENT;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/* only called from syscall */
+int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
+ void *key, void *value, u64 map_flags)
+{
+ void *ptr;
+ int ret;
+ u32 ufd = *(u32 *)value;
+
+ ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ ret = htab_map_update_elem(map, key, &ptr, map_flags);
+ if (ret)
+ map->ops->map_fd_put_ptr(map, ptr, false);
+
+ return ret;
+}
+
+static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
+{
+ struct bpf_map *map, *inner_map_meta;
+
+ inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+ if (IS_ERR(inner_map_meta))
+ return inner_map_meta;
+
+ map = htab_map_alloc(attr);
+ if (IS_ERR(map)) {
+ bpf_map_meta_free(inner_map_meta);
+ return map;
+ }
+
+ map->inner_map_meta = inner_map_meta;
+
+ return map;
+}
+
+static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
+
+ if (!inner_map)
+ return NULL;
+
+ return READ_ONCE(*inner_map);
+}
+
+static int htab_of_map_gen_lookup(struct bpf_map *map,
+ struct bpf_insn *insn_buf)
+{
+ struct bpf_insn *insn = insn_buf;
+ const int ret = BPF_REG_0;
+
+ BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+ (void *(*)(struct bpf_map *map, void *key))NULL));
+ *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+ *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
+ *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+ offsetof(struct htab_elem, key) +
+ round_up(map->key_size, 8));
+ *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
+
+ return insn - insn_buf;
+}
+
+static void htab_of_map_free(struct bpf_map *map)
+{
+ bpf_map_meta_free(map->inner_map_meta);
+ fd_htab_map_free(map);
+}
+
+const struct bpf_map_ops htab_of_maps_map_ops = {
+ .map_alloc_check = fd_htab_map_alloc_check,
+ .map_alloc = htab_of_map_alloc,
+ .map_free = htab_of_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_lookup_elem = htab_of_map_lookup_elem,
+ .map_delete_elem = htab_map_delete_elem,
+ .map_fd_get_ptr = bpf_map_fd_get_ptr,
+ .map_fd_put_ptr = bpf_map_fd_put_ptr,
+ .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
+ .map_gen_lookup = htab_of_map_gen_lookup,
+ .map_check_btf = map_check_no_btf,
+ .map_mem_usage = htab_map_mem_usage,
+ BATCH_OPS(htab),
+ .map_btf_id = &htab_map_btf_ids[0],
+};