1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 #include <linux/bpf.h>
14 #include <linux/jhash.h>
15 #include <linux/filter.h>
16 #include "percpu_freelist.h"
17 #include "bpf_lru_list.h"
20 struct hlist_head head;
26 struct bucket *buckets;
29 struct pcpu_freelist freelist;
32 void __percpu *extra_elems;
33 atomic_t count; /* number of elements in this hashtable */
34 u32 n_buckets; /* number of hash buckets */
35 u32 elem_size; /* size of each element in bytes */
38 enum extra_elem_state {
39 HTAB_NOT_AN_EXTRA_ELEM = 0,
44 /* each htab element is struct htab_elem + key + value */
47 struct hlist_node hash_node;
48 struct bpf_htab *htab;
49 struct pcpu_freelist_node fnode;
53 enum extra_elem_state state;
54 struct bpf_lru_node lru_node;
57 char key[0] __aligned(8);
60 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
62 static bool htab_is_lru(const struct bpf_htab *htab)
64 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
65 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
68 static bool htab_is_percpu(const struct bpf_htab *htab)
70 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
71 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
74 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
77 *(void __percpu **)(l->key + key_size) = pptr;
80 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
82 return *(void __percpu **)(l->key + key_size);
85 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
87 return (struct htab_elem *) (htab->elems + i * htab->elem_size);
90 static void htab_free_elems(struct bpf_htab *htab)
94 if (!htab_is_percpu(htab))
97 for (i = 0; i < htab->map.max_entries; i++) {
100 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
105 bpf_map_area_free(htab->elems);
108 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
111 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
115 l = container_of(node, struct htab_elem, lru_node);
116 memcpy(l->key, key, htab->map.key_size);
123 static int prealloc_init(struct bpf_htab *htab)
125 int err = -ENOMEM, i;
127 htab->elems = bpf_map_area_alloc(htab->elem_size *
128 htab->map.max_entries);
132 if (!htab_is_percpu(htab))
133 goto skip_percpu_elems;
135 for (i = 0; i < htab->map.max_entries; i++) {
136 u32 size = round_up(htab->map.value_size, 8);
139 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
142 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
147 if (htab_is_lru(htab))
148 err = bpf_lru_init(&htab->lru,
149 htab->map.map_flags & BPF_F_NO_COMMON_LRU,
150 offsetof(struct htab_elem, hash) -
151 offsetof(struct htab_elem, lru_node),
152 htab_lru_map_delete_node,
155 err = pcpu_freelist_init(&htab->freelist);
160 if (htab_is_lru(htab))
161 bpf_lru_populate(&htab->lru, htab->elems,
162 offsetof(struct htab_elem, lru_node),
163 htab->elem_size, htab->map.max_entries);
165 pcpu_freelist_populate(&htab->freelist, htab->elems,
166 htab->elem_size, htab->map.max_entries);
171 htab_free_elems(htab);
175 static void prealloc_destroy(struct bpf_htab *htab)
177 htab_free_elems(htab);
179 if (htab_is_lru(htab))
180 bpf_lru_destroy(&htab->lru);
182 pcpu_freelist_destroy(&htab->freelist);
185 static int alloc_extra_elems(struct bpf_htab *htab)
190 pptr = __alloc_percpu_gfp(htab->elem_size, 8, GFP_USER | __GFP_NOWARN);
194 for_each_possible_cpu(cpu) {
195 ((struct htab_elem *)per_cpu_ptr(pptr, cpu))->state =
196 HTAB_EXTRA_ELEM_FREE;
198 htab->extra_elems = pptr;
202 /* Called from syscall */
203 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
205 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
206 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
207 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
208 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
209 /* percpu_lru means each cpu has its own LRU list.
210 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
211 * the map's value itself is percpu. percpu_lru has
212 * nothing to do with the map's value.
214 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
215 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
216 struct bpf_htab *htab;
220 if (lru && !capable(CAP_SYS_ADMIN))
221 /* LRU implementation is much complicated than other
222 * maps. Hence, limit to CAP_SYS_ADMIN for now.
224 return ERR_PTR(-EPERM);
226 if (attr->map_flags & ~(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU))
227 /* reserved bits should not be used */
228 return ERR_PTR(-EINVAL);
230 if (!lru && percpu_lru)
231 return ERR_PTR(-EINVAL);
233 if (lru && !prealloc)
234 return ERR_PTR(-ENOTSUPP);
236 htab = kzalloc(sizeof(*htab), GFP_USER);
238 return ERR_PTR(-ENOMEM);
240 /* mandatory map attributes */
241 htab->map.map_type = attr->map_type;
242 htab->map.key_size = attr->key_size;
243 htab->map.value_size = attr->value_size;
244 htab->map.max_entries = attr->max_entries;
245 htab->map.map_flags = attr->map_flags;
247 /* check sanity of attributes.
248 * value_size == 0 may be allowed in the future to use map as a set
251 if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||
252 htab->map.value_size == 0)
256 /* ensure each CPU's lru list has >=1 elements.
257 * since we are at it, make each lru list has the same
258 * number of elements.
260 htab->map.max_entries = roundup(attr->max_entries,
261 num_possible_cpus());
262 if (htab->map.max_entries < attr->max_entries)
263 htab->map.max_entries = rounddown(attr->max_entries,
264 num_possible_cpus());
267 /* hash table size must be power of 2 */
268 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
271 if (htab->map.key_size > MAX_BPF_STACK)
272 /* eBPF programs initialize keys on stack, so they cannot be
273 * larger than max stack size
277 if (htab->map.value_size >= KMALLOC_MAX_SIZE -
278 MAX_BPF_STACK - sizeof(struct htab_elem))
279 /* if value_size is bigger, the user space won't be able to
280 * access the elements via bpf syscall. This check also makes
281 * sure that the elem_size doesn't overflow and it's
282 * kmalloc-able later in htab_map_update_elem()
286 if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE)
287 /* make sure the size for pcpu_alloc() is reasonable */
290 htab->elem_size = sizeof(struct htab_elem) +
291 round_up(htab->map.key_size, 8);
293 htab->elem_size += sizeof(void *);
295 htab->elem_size += round_up(htab->map.value_size, 8);
297 /* prevent zero size kmalloc and check for u32 overflow */
298 if (htab->n_buckets == 0 ||
299 htab->n_buckets > U32_MAX / sizeof(struct bucket))
302 cost = (u64) htab->n_buckets * sizeof(struct bucket) +
303 (u64) htab->elem_size * htab->map.max_entries;
306 cost += (u64) round_up(htab->map.value_size, 8) *
307 num_possible_cpus() * htab->map.max_entries;
309 cost += (u64) htab->elem_size * num_possible_cpus();
311 if (cost >= U32_MAX - PAGE_SIZE)
312 /* make sure page count doesn't overflow */
315 htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
317 /* if map size is larger than memlock limit, reject it early */
318 err = bpf_map_precharge_memlock(htab->map.pages);
323 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
324 sizeof(struct bucket));
328 for (i = 0; i < htab->n_buckets; i++) {
329 INIT_HLIST_HEAD(&htab->buckets[i].head);
330 raw_spin_lock_init(&htab->buckets[i].lock);
333 if (!percpu && !lru) {
334 /* lru itself can remove the least used element, so
335 * there is no need for an extra elem during map_update.
337 err = alloc_extra_elems(htab);
343 err = prealloc_init(htab);
345 goto free_extra_elems;
351 free_percpu(htab->extra_elems);
353 bpf_map_area_free(htab->buckets);
359 static inline u32 htab_map_hash(const void *key, u32 key_len)
361 return jhash(key, key_len, 0);
364 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
366 return &htab->buckets[hash & (htab->n_buckets - 1)];
369 static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash)
371 return &__select_bucket(htab, hash)->head;
374 static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,
375 void *key, u32 key_size)
379 hlist_for_each_entry_rcu(l, head, hash_node)
380 if (l->hash == hash && !memcmp(&l->key, key, key_size))
386 /* Called from syscall or from eBPF program */
387 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
389 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
390 struct hlist_head *head;
394 /* Must be called with rcu_read_lock. */
395 WARN_ON_ONCE(!rcu_read_lock_held());
397 key_size = map->key_size;
399 hash = htab_map_hash(key, key_size);
401 head = select_bucket(htab, hash);
403 l = lookup_elem_raw(head, hash, key, key_size);
408 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
410 struct htab_elem *l = __htab_map_lookup_elem(map, key);
413 return l->key + round_up(map->key_size, 8);
418 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
420 struct htab_elem *l = __htab_map_lookup_elem(map, key);
423 bpf_lru_node_set_ref(&l->lru_node);
424 return l->key + round_up(map->key_size, 8);
430 /* It is called from the bpf_lru_list when the LRU needs to delete
431 * older elements from the htab.
433 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
435 struct bpf_htab *htab = (struct bpf_htab *)arg;
436 struct htab_elem *l, *tgt_l;
437 struct hlist_head *head;
441 tgt_l = container_of(node, struct htab_elem, lru_node);
442 b = __select_bucket(htab, tgt_l->hash);
445 raw_spin_lock_irqsave(&b->lock, flags);
447 hlist_for_each_entry_rcu(l, head, hash_node)
449 hlist_del_rcu(&l->hash_node);
453 raw_spin_unlock_irqrestore(&b->lock, flags);
458 /* Called from syscall */
459 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
461 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
462 struct hlist_head *head;
463 struct htab_elem *l, *next_l;
467 WARN_ON_ONCE(!rcu_read_lock_held());
469 key_size = map->key_size;
471 hash = htab_map_hash(key, key_size);
473 head = select_bucket(htab, hash);
476 l = lookup_elem_raw(head, hash, key, key_size);
480 goto find_first_elem;
483 /* key was found, get next key in the same bucket */
484 next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)),
485 struct htab_elem, hash_node);
488 /* if next elem in this hash list is non-zero, just return it */
489 memcpy(next_key, next_l->key, key_size);
493 /* no more elements in this hash list, go to the next bucket */
494 i = hash & (htab->n_buckets - 1);
498 /* iterate over buckets */
499 for (; i < htab->n_buckets; i++) {
500 head = select_bucket(htab, i);
502 /* pick first element in the bucket */
503 next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
504 struct htab_elem, hash_node);
506 /* if it's not empty, just return it */
507 memcpy(next_key, next_l->key, key_size);
512 /* iterated over all buckets and all elements */
516 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
518 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
519 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
523 static void htab_elem_free_rcu(struct rcu_head *head)
525 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
526 struct bpf_htab *htab = l->htab;
528 /* must increment bpf_prog_active to avoid kprobe+bpf triggering while
529 * we're calling kfree, otherwise deadlock is possible if kprobes
530 * are placed somewhere inside of slub
533 __this_cpu_inc(bpf_prog_active);
534 htab_elem_free(htab, l);
535 __this_cpu_dec(bpf_prog_active);
539 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
541 if (l->state == HTAB_EXTRA_ELEM_USED) {
542 l->state = HTAB_EXTRA_ELEM_FREE;
546 if (!(htab->map.map_flags & BPF_F_NO_PREALLOC)) {
547 pcpu_freelist_push(&htab->freelist, &l->fnode);
549 atomic_dec(&htab->count);
551 call_rcu(&l->rcu, htab_elem_free_rcu);
555 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
556 void *value, bool onallcpus)
559 /* copy true value_size bytes */
560 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
562 u32 size = round_up(htab->map.value_size, 8);
565 for_each_possible_cpu(cpu) {
566 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
573 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
574 void *value, u32 key_size, u32 hash,
575 bool percpu, bool onallcpus,
576 bool old_elem_exists)
578 u32 size = htab->map.value_size;
579 bool prealloc = !(htab->map.map_flags & BPF_F_NO_PREALLOC);
580 struct htab_elem *l_new;
585 l_new = (struct htab_elem *)pcpu_freelist_pop(&htab->freelist);
589 if (atomic_inc_return(&htab->count) > htab->map.max_entries) {
590 atomic_dec(&htab->count);
593 l_new = kmalloc(htab->elem_size,
594 GFP_ATOMIC | __GFP_NOWARN);
596 return ERR_PTR(-ENOMEM);
601 if (!old_elem_exists)
604 /* if we're updating the existing element and the hash table
605 * is full, use per-cpu extra elems
607 l_new = this_cpu_ptr(htab->extra_elems);
608 if (l_new->state != HTAB_EXTRA_ELEM_FREE)
609 return ERR_PTR(-E2BIG);
610 l_new->state = HTAB_EXTRA_ELEM_USED;
612 l_new->state = HTAB_NOT_AN_EXTRA_ELEM;
615 memcpy(l_new->key, key, key_size);
617 /* round up value_size to 8 bytes */
618 size = round_up(size, 8);
621 pptr = htab_elem_get_ptr(l_new, key_size);
623 /* alloc_percpu zero-fills */
624 pptr = __alloc_percpu_gfp(size, 8,
625 GFP_ATOMIC | __GFP_NOWARN);
628 return ERR_PTR(-ENOMEM);
632 pcpu_copy_value(htab, pptr, value, onallcpus);
635 htab_elem_set_ptr(l_new, key_size, pptr);
637 memcpy(l_new->key + round_up(key_size, 8), value, size);
644 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
647 if (l_old && map_flags == BPF_NOEXIST)
648 /* elem already exists */
651 if (!l_old && map_flags == BPF_EXIST)
652 /* elem doesn't exist, cannot update it */
658 /* Called from syscall or from eBPF program */
659 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
662 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
663 struct htab_elem *l_new = NULL, *l_old;
664 struct hlist_head *head;
670 if (unlikely(map_flags > BPF_EXIST))
674 WARN_ON_ONCE(!rcu_read_lock_held());
676 key_size = map->key_size;
678 hash = htab_map_hash(key, key_size);
680 b = __select_bucket(htab, hash);
683 /* bpf_map_update_elem() can be called in_irq() */
684 raw_spin_lock_irqsave(&b->lock, flags);
686 l_old = lookup_elem_raw(head, hash, key, key_size);
688 ret = check_flags(htab, l_old, map_flags);
692 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
695 /* all pre-allocated elements are in use or memory exhausted */
696 ret = PTR_ERR(l_new);
700 /* add new element to the head of the list, so that
701 * concurrent search will find it before old elem
703 hlist_add_head_rcu(&l_new->hash_node, head);
705 hlist_del_rcu(&l_old->hash_node);
706 free_htab_elem(htab, l_old);
710 raw_spin_unlock_irqrestore(&b->lock, flags);
714 static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
717 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
718 struct htab_elem *l_new, *l_old = NULL;
719 struct hlist_head *head;
725 if (unlikely(map_flags > BPF_EXIST))
729 WARN_ON_ONCE(!rcu_read_lock_held());
731 key_size = map->key_size;
733 hash = htab_map_hash(key, key_size);
735 b = __select_bucket(htab, hash);
738 /* For LRU, we need to alloc before taking bucket's
739 * spinlock because getting free nodes from LRU may need
740 * to remove older elements from htab and this removal
741 * operation will need a bucket lock.
743 l_new = prealloc_lru_pop(htab, key, hash);
746 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
748 /* bpf_map_update_elem() can be called in_irq() */
749 raw_spin_lock_irqsave(&b->lock, flags);
751 l_old = lookup_elem_raw(head, hash, key, key_size);
753 ret = check_flags(htab, l_old, map_flags);
757 /* add new element to the head of the list, so that
758 * concurrent search will find it before old elem
760 hlist_add_head_rcu(&l_new->hash_node, head);
762 bpf_lru_node_set_ref(&l_new->lru_node);
763 hlist_del_rcu(&l_old->hash_node);
768 raw_spin_unlock_irqrestore(&b->lock, flags);
771 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
773 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
778 static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
779 void *value, u64 map_flags,
782 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
783 struct htab_elem *l_new = NULL, *l_old;
784 struct hlist_head *head;
790 if (unlikely(map_flags > BPF_EXIST))
794 WARN_ON_ONCE(!rcu_read_lock_held());
796 key_size = map->key_size;
798 hash = htab_map_hash(key, key_size);
800 b = __select_bucket(htab, hash);
803 /* bpf_map_update_elem() can be called in_irq() */
804 raw_spin_lock_irqsave(&b->lock, flags);
806 l_old = lookup_elem_raw(head, hash, key, key_size);
808 ret = check_flags(htab, l_old, map_flags);
813 /* per-cpu hash map can update value in-place */
814 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
817 l_new = alloc_htab_elem(htab, key, value, key_size,
818 hash, true, onallcpus, false);
820 ret = PTR_ERR(l_new);
823 hlist_add_head_rcu(&l_new->hash_node, head);
827 raw_spin_unlock_irqrestore(&b->lock, flags);
831 static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
832 void *value, u64 map_flags,
835 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
836 struct htab_elem *l_new = NULL, *l_old;
837 struct hlist_head *head;
843 if (unlikely(map_flags > BPF_EXIST))
847 WARN_ON_ONCE(!rcu_read_lock_held());
849 key_size = map->key_size;
851 hash = htab_map_hash(key, key_size);
853 b = __select_bucket(htab, hash);
856 /* For LRU, we need to alloc before taking bucket's
857 * spinlock because LRU's elem alloc may need
858 * to remove older elem from htab and this removal
859 * operation will need a bucket lock.
861 if (map_flags != BPF_EXIST) {
862 l_new = prealloc_lru_pop(htab, key, hash);
867 /* bpf_map_update_elem() can be called in_irq() */
868 raw_spin_lock_irqsave(&b->lock, flags);
870 l_old = lookup_elem_raw(head, hash, key, key_size);
872 ret = check_flags(htab, l_old, map_flags);
877 bpf_lru_node_set_ref(&l_old->lru_node);
879 /* per-cpu hash map can update value in-place */
880 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
883 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
885 hlist_add_head_rcu(&l_new->hash_node, head);
890 raw_spin_unlock_irqrestore(&b->lock, flags);
892 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
896 static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
897 void *value, u64 map_flags)
899 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
902 static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
903 void *value, u64 map_flags)
905 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
909 /* Called from syscall or from eBPF program */
910 static int htab_map_delete_elem(struct bpf_map *map, void *key)
912 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
913 struct hlist_head *head;
920 WARN_ON_ONCE(!rcu_read_lock_held());
922 key_size = map->key_size;
924 hash = htab_map_hash(key, key_size);
925 b = __select_bucket(htab, hash);
928 raw_spin_lock_irqsave(&b->lock, flags);
930 l = lookup_elem_raw(head, hash, key, key_size);
933 hlist_del_rcu(&l->hash_node);
934 free_htab_elem(htab, l);
938 raw_spin_unlock_irqrestore(&b->lock, flags);
942 static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
944 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
945 struct hlist_head *head;
952 WARN_ON_ONCE(!rcu_read_lock_held());
954 key_size = map->key_size;
956 hash = htab_map_hash(key, key_size);
957 b = __select_bucket(htab, hash);
960 raw_spin_lock_irqsave(&b->lock, flags);
962 l = lookup_elem_raw(head, hash, key, key_size);
965 hlist_del_rcu(&l->hash_node);
969 raw_spin_unlock_irqrestore(&b->lock, flags);
971 bpf_lru_push_free(&htab->lru, &l->lru_node);
975 static void delete_all_elements(struct bpf_htab *htab)
979 for (i = 0; i < htab->n_buckets; i++) {
980 struct hlist_head *head = select_bucket(htab, i);
981 struct hlist_node *n;
984 hlist_for_each_entry_safe(l, n, head, hash_node) {
985 hlist_del_rcu(&l->hash_node);
986 if (l->state != HTAB_EXTRA_ELEM_USED)
987 htab_elem_free(htab, l);
991 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
992 static void htab_map_free(struct bpf_map *map)
994 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
996 /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
997 * so the programs (can be more than one that used this map) were
998 * disconnected from events. Wait for outstanding critical sections in
999 * these programs to complete
1003 /* some of free_htab_elem() callbacks for elements of this map may
1004 * not have executed. Wait for them.
1007 if (htab->map.map_flags & BPF_F_NO_PREALLOC)
1008 delete_all_elements(htab);
1010 prealloc_destroy(htab);
1012 free_percpu(htab->extra_elems);
1013 bpf_map_area_free(htab->buckets);
1017 static const struct bpf_map_ops htab_ops = {
1018 .map_alloc = htab_map_alloc,
1019 .map_free = htab_map_free,
1020 .map_get_next_key = htab_map_get_next_key,
1021 .map_lookup_elem = htab_map_lookup_elem,
1022 .map_update_elem = htab_map_update_elem,
1023 .map_delete_elem = htab_map_delete_elem,
1026 static struct bpf_map_type_list htab_type __read_mostly = {
1028 .type = BPF_MAP_TYPE_HASH,
1031 static const struct bpf_map_ops htab_lru_ops = {
1032 .map_alloc = htab_map_alloc,
1033 .map_free = htab_map_free,
1034 .map_get_next_key = htab_map_get_next_key,
1035 .map_lookup_elem = htab_lru_map_lookup_elem,
1036 .map_update_elem = htab_lru_map_update_elem,
1037 .map_delete_elem = htab_lru_map_delete_elem,
1040 static struct bpf_map_type_list htab_lru_type __read_mostly = {
1041 .ops = &htab_lru_ops,
1042 .type = BPF_MAP_TYPE_LRU_HASH,
1045 /* Called from eBPF program */
1046 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1048 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1051 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1056 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1058 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1061 bpf_lru_node_set_ref(&l->lru_node);
1062 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1068 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1070 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1071 struct htab_elem *l;
1072 void __percpu *pptr;
1077 /* per_cpu areas are zero-filled and bpf programs can only
1078 * access 'value_size' of them, so copying rounded areas
1079 * will not leak any kernel data
1081 size = round_up(map->value_size, 8);
1083 l = __htab_map_lookup_elem(map, key);
1086 if (htab_is_lru(htab))
1087 bpf_lru_node_set_ref(&l->lru_node);
1088 pptr = htab_elem_get_ptr(l, map->key_size);
1089 for_each_possible_cpu(cpu) {
1090 bpf_long_memcpy(value + off,
1091 per_cpu_ptr(pptr, cpu), size);
1100 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1103 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1107 if (htab_is_lru(htab))
1108 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1111 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1118 static const struct bpf_map_ops htab_percpu_ops = {
1119 .map_alloc = htab_map_alloc,
1120 .map_free = htab_map_free,
1121 .map_get_next_key = htab_map_get_next_key,
1122 .map_lookup_elem = htab_percpu_map_lookup_elem,
1123 .map_update_elem = htab_percpu_map_update_elem,
1124 .map_delete_elem = htab_map_delete_elem,
1127 static struct bpf_map_type_list htab_percpu_type __read_mostly = {
1128 .ops = &htab_percpu_ops,
1129 .type = BPF_MAP_TYPE_PERCPU_HASH,
1132 static const struct bpf_map_ops htab_lru_percpu_ops = {
1133 .map_alloc = htab_map_alloc,
1134 .map_free = htab_map_free,
1135 .map_get_next_key = htab_map_get_next_key,
1136 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
1137 .map_update_elem = htab_lru_percpu_map_update_elem,
1138 .map_delete_elem = htab_lru_map_delete_elem,
1141 static struct bpf_map_type_list htab_lru_percpu_type __read_mostly = {
1142 .ops = &htab_lru_percpu_ops,
1143 .type = BPF_MAP_TYPE_LRU_PERCPU_HASH,
1146 static int __init register_htab_map(void)
1148 bpf_register_map_type(&htab_type);
1149 bpf_register_map_type(&htab_percpu_type);
1150 bpf_register_map_type(&htab_lru_type);
1151 bpf_register_map_type(&htab_lru_percpu_type);
1154 late_initcall(register_htab_map);