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 <linux/rculist_nulls.h>
17 #include "percpu_freelist.h"
18 #include "bpf_lru_list.h"
19 #include "map_in_map.h"
21 #define HTAB_CREATE_FLAG_MASK \
22 (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
23 BPF_F_RDONLY | BPF_F_WRONLY)
26 struct hlist_nulls_head head;
32 struct bucket *buckets;
35 struct pcpu_freelist freelist;
38 struct htab_elem *__percpu *extra_elems;
39 atomic_t count; /* number of elements in this hashtable */
40 u32 n_buckets; /* number of hash buckets */
41 u32 elem_size; /* size of each element in bytes */
44 /* each htab element is struct htab_elem + key + value */
47 struct hlist_nulls_node hash_node;
51 struct bpf_htab *htab;
52 struct pcpu_freelist_node fnode;
58 struct bpf_lru_node lru_node;
61 char key[0] __aligned(8);
64 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
66 static bool htab_is_lru(const struct bpf_htab *htab)
68 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
69 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
72 static bool htab_is_percpu(const struct bpf_htab *htab)
74 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
75 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
78 static bool htab_is_prealloc(const struct bpf_htab *htab)
80 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
83 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
86 *(void __percpu **)(l->key + key_size) = pptr;
89 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
91 return *(void __percpu **)(l->key + key_size);
94 static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
96 return *(void **)(l->key + roundup(map->key_size, 8));
99 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
101 return (struct htab_elem *) (htab->elems + i * htab->elem_size);
104 static void htab_free_elems(struct bpf_htab *htab)
108 if (!htab_is_percpu(htab))
111 for (i = 0; i < htab->map.max_entries; i++) {
114 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
120 bpf_map_area_free(htab->elems);
123 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
126 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
130 l = container_of(node, struct htab_elem, lru_node);
131 memcpy(l->key, key, htab->map.key_size);
138 static int prealloc_init(struct bpf_htab *htab)
140 u32 num_entries = htab->map.max_entries;
141 int err = -ENOMEM, i;
143 if (!htab_is_percpu(htab) && !htab_is_lru(htab))
144 num_entries += num_possible_cpus();
146 htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
147 htab->map.numa_node);
151 if (!htab_is_percpu(htab))
152 goto skip_percpu_elems;
154 for (i = 0; i < num_entries; i++) {
155 u32 size = round_up(htab->map.value_size, 8);
158 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
161 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
167 if (htab_is_lru(htab))
168 err = bpf_lru_init(&htab->lru,
169 htab->map.map_flags & BPF_F_NO_COMMON_LRU,
170 offsetof(struct htab_elem, hash) -
171 offsetof(struct htab_elem, lru_node),
172 htab_lru_map_delete_node,
175 err = pcpu_freelist_init(&htab->freelist);
180 if (htab_is_lru(htab))
181 bpf_lru_populate(&htab->lru, htab->elems,
182 offsetof(struct htab_elem, lru_node),
183 htab->elem_size, num_entries);
185 pcpu_freelist_populate(&htab->freelist,
186 htab->elems + offsetof(struct htab_elem, fnode),
187 htab->elem_size, num_entries);
192 htab_free_elems(htab);
196 static void prealloc_destroy(struct bpf_htab *htab)
198 htab_free_elems(htab);
200 if (htab_is_lru(htab))
201 bpf_lru_destroy(&htab->lru);
203 pcpu_freelist_destroy(&htab->freelist);
206 static int alloc_extra_elems(struct bpf_htab *htab)
208 struct htab_elem *__percpu *pptr, *l_new;
209 struct pcpu_freelist_node *l;
212 pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
213 GFP_USER | __GFP_NOWARN);
217 for_each_possible_cpu(cpu) {
218 l = pcpu_freelist_pop(&htab->freelist);
219 /* pop will succeed, since prealloc_init()
220 * preallocated extra num_possible_cpus elements
222 l_new = container_of(l, struct htab_elem, fnode);
223 *per_cpu_ptr(pptr, cpu) = l_new;
225 htab->extra_elems = pptr;
229 /* Called from syscall */
230 static int htab_map_alloc_check(union bpf_attr *attr)
232 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
233 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
234 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
235 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
236 /* percpu_lru means each cpu has its own LRU list.
237 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
238 * the map's value itself is percpu. percpu_lru has
239 * nothing to do with the map's value.
241 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
242 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
243 int numa_node = bpf_map_attr_numa_node(attr);
245 BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
246 offsetof(struct htab_elem, hash_node.pprev));
247 BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
248 offsetof(struct htab_elem, hash_node.pprev));
250 if (lru && !capable(CAP_SYS_ADMIN))
251 /* LRU implementation is much complicated than other
252 * maps. Hence, limit to CAP_SYS_ADMIN for now.
256 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)
257 /* reserved bits should not be used */
260 if (!lru && percpu_lru)
263 if (lru && !prealloc)
266 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
269 /* check sanity of attributes.
270 * value_size == 0 may be allowed in the future to use map as a set
272 if (attr->max_entries == 0 || attr->key_size == 0 ||
273 attr->value_size == 0)
276 if (attr->key_size > MAX_BPF_STACK)
277 /* eBPF programs initialize keys on stack, so they cannot be
278 * larger than max stack size
282 if (attr->value_size >= KMALLOC_MAX_SIZE -
283 MAX_BPF_STACK - sizeof(struct htab_elem))
284 /* if value_size is bigger, the user space won't be able to
285 * access the elements via bpf syscall. This check also makes
286 * sure that the elem_size doesn't overflow and it's
287 * kmalloc-able later in htab_map_update_elem()
294 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
296 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
297 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
298 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
299 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
300 /* percpu_lru means each cpu has its own LRU list.
301 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
302 * the map's value itself is percpu. percpu_lru has
303 * nothing to do with the map's value.
305 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
306 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
307 struct bpf_htab *htab;
311 htab = kzalloc(sizeof(*htab), GFP_USER);
313 return ERR_PTR(-ENOMEM);
315 bpf_map_init_from_attr(&htab->map, attr);
318 /* ensure each CPU's lru list has >=1 elements.
319 * since we are at it, make each lru list has the same
320 * number of elements.
322 htab->map.max_entries = roundup(attr->max_entries,
323 num_possible_cpus());
324 if (htab->map.max_entries < attr->max_entries)
325 htab->map.max_entries = rounddown(attr->max_entries,
326 num_possible_cpus());
329 /* hash table size must be power of 2 */
330 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
332 htab->elem_size = sizeof(struct htab_elem) +
333 round_up(htab->map.key_size, 8);
335 htab->elem_size += sizeof(void *);
337 htab->elem_size += round_up(htab->map.value_size, 8);
340 /* prevent zero size kmalloc and check for u32 overflow */
341 if (htab->n_buckets == 0 ||
342 htab->n_buckets > U32_MAX / sizeof(struct bucket))
345 cost = (u64) htab->n_buckets * sizeof(struct bucket) +
346 (u64) htab->elem_size * htab->map.max_entries;
349 cost += (u64) round_up(htab->map.value_size, 8) *
350 num_possible_cpus() * htab->map.max_entries;
352 cost += (u64) htab->elem_size * num_possible_cpus();
354 if (cost >= U32_MAX - PAGE_SIZE)
355 /* make sure page count doesn't overflow */
358 htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
360 /* if map size is larger than memlock limit, reject it early */
361 err = bpf_map_precharge_memlock(htab->map.pages);
366 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
367 sizeof(struct bucket),
368 htab->map.numa_node);
372 for (i = 0; i < htab->n_buckets; i++) {
373 INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
374 raw_spin_lock_init(&htab->buckets[i].lock);
378 err = prealloc_init(htab);
382 if (!percpu && !lru) {
383 /* lru itself can remove the least used element, so
384 * there is no need for an extra elem during map_update.
386 err = alloc_extra_elems(htab);
395 prealloc_destroy(htab);
397 bpf_map_area_free(htab->buckets);
403 static inline u32 htab_map_hash(const void *key, u32 key_len)
405 return jhash(key, key_len, 0);
408 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
410 return &htab->buckets[hash & (htab->n_buckets - 1)];
413 static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
415 return &__select_bucket(htab, hash)->head;
418 /* this lookup function can only be called with bucket lock taken */
419 static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
420 void *key, u32 key_size)
422 struct hlist_nulls_node *n;
425 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
426 if (l->hash == hash && !memcmp(&l->key, key, key_size))
432 /* can be called without bucket lock. it will repeat the loop in
433 * the unlikely event when elements moved from one bucket into another
434 * while link list is being walked
436 static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
438 u32 key_size, u32 n_buckets)
440 struct hlist_nulls_node *n;
444 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
445 if (l->hash == hash && !memcmp(&l->key, key, key_size))
448 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
454 /* Called from syscall or from eBPF program directly, so
455 * arguments have to match bpf_map_lookup_elem() exactly.
456 * The return value is adjusted by BPF instructions
457 * in htab_map_gen_lookup().
459 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
461 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
462 struct hlist_nulls_head *head;
466 /* Must be called with rcu_read_lock. */
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);
475 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
480 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
482 struct htab_elem *l = __htab_map_lookup_elem(map, key);
485 return l->key + round_up(map->key_size, 8);
490 /* inline bpf_map_lookup_elem() call.
493 * bpf_map_lookup_elem
494 * map->ops->map_lookup_elem
495 * htab_map_lookup_elem
496 * __htab_map_lookup_elem
499 * __htab_map_lookup_elem
501 static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
503 struct bpf_insn *insn = insn_buf;
504 const int ret = BPF_REG_0;
506 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
507 (void *(*)(struct bpf_map *map, void *key))NULL));
508 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
509 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
510 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
511 offsetof(struct htab_elem, key) +
512 round_up(map->key_size, 8));
513 return insn - insn_buf;
516 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
518 struct htab_elem *l = __htab_map_lookup_elem(map, key);
521 bpf_lru_node_set_ref(&l->lru_node);
522 return l->key + round_up(map->key_size, 8);
528 static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
529 struct bpf_insn *insn_buf)
531 struct bpf_insn *insn = insn_buf;
532 const int ret = BPF_REG_0;
533 const int ref_reg = BPF_REG_1;
535 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
536 (void *(*)(struct bpf_map *map, void *key))NULL));
537 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
538 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
539 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
540 offsetof(struct htab_elem, lru_node) +
541 offsetof(struct bpf_lru_node, ref));
542 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
543 *insn++ = BPF_ST_MEM(BPF_B, ret,
544 offsetof(struct htab_elem, lru_node) +
545 offsetof(struct bpf_lru_node, ref),
547 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
548 offsetof(struct htab_elem, key) +
549 round_up(map->key_size, 8));
550 return insn - insn_buf;
553 /* It is called from the bpf_lru_list when the LRU needs to delete
554 * older elements from the htab.
556 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
558 struct bpf_htab *htab = (struct bpf_htab *)arg;
559 struct htab_elem *l = NULL, *tgt_l;
560 struct hlist_nulls_head *head;
561 struct hlist_nulls_node *n;
565 tgt_l = container_of(node, struct htab_elem, lru_node);
566 b = __select_bucket(htab, tgt_l->hash);
569 raw_spin_lock_irqsave(&b->lock, flags);
571 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
573 hlist_nulls_del_rcu(&l->hash_node);
577 raw_spin_unlock_irqrestore(&b->lock, flags);
582 /* Called from syscall */
583 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
585 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
586 struct hlist_nulls_head *head;
587 struct htab_elem *l, *next_l;
591 WARN_ON_ONCE(!rcu_read_lock_held());
593 key_size = map->key_size;
596 goto find_first_elem;
598 hash = htab_map_hash(key, key_size);
600 head = select_bucket(htab, hash);
603 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
606 goto find_first_elem;
608 /* key was found, get next key in the same bucket */
609 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
610 struct htab_elem, hash_node);
613 /* if next elem in this hash list is non-zero, just return it */
614 memcpy(next_key, next_l->key, key_size);
618 /* no more elements in this hash list, go to the next bucket */
619 i = hash & (htab->n_buckets - 1);
623 /* iterate over buckets */
624 for (; i < htab->n_buckets; i++) {
625 head = select_bucket(htab, i);
627 /* pick first element in the bucket */
628 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
629 struct htab_elem, hash_node);
631 /* if it's not empty, just return it */
632 memcpy(next_key, next_l->key, key_size);
637 /* iterated over all buckets and all elements */
641 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
643 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
644 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
648 static void htab_elem_free_rcu(struct rcu_head *head)
650 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
651 struct bpf_htab *htab = l->htab;
653 /* must increment bpf_prog_active to avoid kprobe+bpf triggering while
654 * we're calling kfree, otherwise deadlock is possible if kprobes
655 * are placed somewhere inside of slub
658 __this_cpu_inc(bpf_prog_active);
659 htab_elem_free(htab, l);
660 __this_cpu_dec(bpf_prog_active);
664 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
666 struct bpf_map *map = &htab->map;
668 if (map->ops->map_fd_put_ptr) {
669 void *ptr = fd_htab_map_get_ptr(map, l);
671 map->ops->map_fd_put_ptr(ptr);
674 if (htab_is_prealloc(htab)) {
675 pcpu_freelist_push(&htab->freelist, &l->fnode);
677 atomic_dec(&htab->count);
679 call_rcu(&l->rcu, htab_elem_free_rcu);
683 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
684 void *value, bool onallcpus)
687 /* copy true value_size bytes */
688 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
690 u32 size = round_up(htab->map.value_size, 8);
693 for_each_possible_cpu(cpu) {
694 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
701 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
703 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
707 static u32 htab_size_value(const struct bpf_htab *htab, bool percpu)
709 u32 size = htab->map.value_size;
711 if (percpu || fd_htab_map_needs_adjust(htab))
712 size = round_up(size, 8);
716 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
717 void *value, u32 key_size, u32 hash,
718 bool percpu, bool onallcpus,
719 struct htab_elem *old_elem)
721 u32 size = htab_size_value(htab, percpu);
722 bool prealloc = htab_is_prealloc(htab);
723 struct htab_elem *l_new, **pl_new;
728 /* if we're updating the existing element,
729 * use per-cpu extra elems to avoid freelist_pop/push
731 pl_new = this_cpu_ptr(htab->extra_elems);
735 struct pcpu_freelist_node *l;
737 l = pcpu_freelist_pop(&htab->freelist);
739 return ERR_PTR(-E2BIG);
740 l_new = container_of(l, struct htab_elem, fnode);
743 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
745 /* when map is full and update() is replacing
746 * old element, it's ok to allocate, since
747 * old element will be freed immediately.
748 * Otherwise return an error
750 l_new = ERR_PTR(-E2BIG);
753 l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
754 htab->map.numa_node);
756 l_new = ERR_PTR(-ENOMEM);
761 memcpy(l_new->key, key, key_size);
764 pptr = htab_elem_get_ptr(l_new, key_size);
766 /* alloc_percpu zero-fills */
767 pptr = __alloc_percpu_gfp(size, 8,
768 GFP_ATOMIC | __GFP_NOWARN);
771 l_new = ERR_PTR(-ENOMEM);
776 pcpu_copy_value(htab, pptr, value, onallcpus);
779 htab_elem_set_ptr(l_new, key_size, pptr);
781 memcpy(l_new->key + round_up(key_size, 8), value, size);
787 atomic_dec(&htab->count);
791 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
794 if (l_old && map_flags == BPF_NOEXIST)
795 /* elem already exists */
798 if (!l_old && map_flags == BPF_EXIST)
799 /* elem doesn't exist, cannot update it */
805 /* Called from syscall or from eBPF program */
806 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
809 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
810 struct htab_elem *l_new = NULL, *l_old;
811 struct hlist_nulls_head *head;
817 if (unlikely(map_flags > BPF_EXIST))
821 WARN_ON_ONCE(!rcu_read_lock_held());
823 key_size = map->key_size;
825 hash = htab_map_hash(key, key_size);
827 b = __select_bucket(htab, hash);
830 /* bpf_map_update_elem() can be called in_irq() */
831 raw_spin_lock_irqsave(&b->lock, flags);
833 l_old = lookup_elem_raw(head, hash, key, key_size);
835 ret = check_flags(htab, l_old, map_flags);
839 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
842 /* all pre-allocated elements are in use or memory exhausted */
843 ret = PTR_ERR(l_new);
847 /* add new element to the head of the list, so that
848 * concurrent search will find it before old elem
850 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
852 hlist_nulls_del_rcu(&l_old->hash_node);
853 if (!htab_is_prealloc(htab))
854 free_htab_elem(htab, l_old);
858 raw_spin_unlock_irqrestore(&b->lock, flags);
862 static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
865 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
866 struct htab_elem *l_new, *l_old = NULL;
867 struct hlist_nulls_head *head;
873 if (unlikely(map_flags > BPF_EXIST))
877 WARN_ON_ONCE(!rcu_read_lock_held());
879 key_size = map->key_size;
881 hash = htab_map_hash(key, key_size);
883 b = __select_bucket(htab, hash);
886 /* For LRU, we need to alloc before taking bucket's
887 * spinlock because getting free nodes from LRU may need
888 * to remove older elements from htab and this removal
889 * operation will need a bucket lock.
891 l_new = prealloc_lru_pop(htab, key, hash);
894 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
896 /* bpf_map_update_elem() can be called in_irq() */
897 raw_spin_lock_irqsave(&b->lock, flags);
899 l_old = lookup_elem_raw(head, hash, key, key_size);
901 ret = check_flags(htab, l_old, map_flags);
905 /* add new element to the head of the list, so that
906 * concurrent search will find it before old elem
908 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
910 bpf_lru_node_set_ref(&l_new->lru_node);
911 hlist_nulls_del_rcu(&l_old->hash_node);
916 raw_spin_unlock_irqrestore(&b->lock, flags);
919 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
921 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
926 static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
927 void *value, u64 map_flags,
930 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
931 struct htab_elem *l_new = NULL, *l_old;
932 struct hlist_nulls_head *head;
938 if (unlikely(map_flags > BPF_EXIST))
942 WARN_ON_ONCE(!rcu_read_lock_held());
944 key_size = map->key_size;
946 hash = htab_map_hash(key, key_size);
948 b = __select_bucket(htab, hash);
951 /* bpf_map_update_elem() can be called in_irq() */
952 raw_spin_lock_irqsave(&b->lock, flags);
954 l_old = lookup_elem_raw(head, hash, key, key_size);
956 ret = check_flags(htab, l_old, map_flags);
961 /* per-cpu hash map can update value in-place */
962 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
965 l_new = alloc_htab_elem(htab, key, value, key_size,
966 hash, true, onallcpus, NULL);
968 ret = PTR_ERR(l_new);
971 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
975 raw_spin_unlock_irqrestore(&b->lock, flags);
979 static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
980 void *value, u64 map_flags,
983 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
984 struct htab_elem *l_new = NULL, *l_old;
985 struct hlist_nulls_head *head;
991 if (unlikely(map_flags > BPF_EXIST))
995 WARN_ON_ONCE(!rcu_read_lock_held());
997 key_size = map->key_size;
999 hash = htab_map_hash(key, key_size);
1001 b = __select_bucket(htab, hash);
1004 /* For LRU, we need to alloc before taking bucket's
1005 * spinlock because LRU's elem alloc may need
1006 * to remove older elem from htab and this removal
1007 * operation will need a bucket lock.
1009 if (map_flags != BPF_EXIST) {
1010 l_new = prealloc_lru_pop(htab, key, hash);
1015 /* bpf_map_update_elem() can be called in_irq() */
1016 raw_spin_lock_irqsave(&b->lock, flags);
1018 l_old = lookup_elem_raw(head, hash, key, key_size);
1020 ret = check_flags(htab, l_old, map_flags);
1025 bpf_lru_node_set_ref(&l_old->lru_node);
1027 /* per-cpu hash map can update value in-place */
1028 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1031 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
1033 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1038 raw_spin_unlock_irqrestore(&b->lock, flags);
1040 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1044 static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1045 void *value, u64 map_flags)
1047 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1050 static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1051 void *value, u64 map_flags)
1053 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1057 /* Called from syscall or from eBPF program */
1058 static int htab_map_delete_elem(struct bpf_map *map, void *key)
1060 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1061 struct hlist_nulls_head *head;
1063 struct htab_elem *l;
1064 unsigned long flags;
1068 WARN_ON_ONCE(!rcu_read_lock_held());
1070 key_size = map->key_size;
1072 hash = htab_map_hash(key, key_size);
1073 b = __select_bucket(htab, hash);
1076 raw_spin_lock_irqsave(&b->lock, flags);
1078 l = lookup_elem_raw(head, hash, key, key_size);
1081 hlist_nulls_del_rcu(&l->hash_node);
1082 free_htab_elem(htab, l);
1086 raw_spin_unlock_irqrestore(&b->lock, flags);
1090 static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1092 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1093 struct hlist_nulls_head *head;
1095 struct htab_elem *l;
1096 unsigned long flags;
1100 WARN_ON_ONCE(!rcu_read_lock_held());
1102 key_size = map->key_size;
1104 hash = htab_map_hash(key, key_size);
1105 b = __select_bucket(htab, hash);
1108 raw_spin_lock_irqsave(&b->lock, flags);
1110 l = lookup_elem_raw(head, hash, key, key_size);
1113 hlist_nulls_del_rcu(&l->hash_node);
1117 raw_spin_unlock_irqrestore(&b->lock, flags);
1119 bpf_lru_push_free(&htab->lru, &l->lru_node);
1123 static void delete_all_elements(struct bpf_htab *htab)
1127 for (i = 0; i < htab->n_buckets; i++) {
1128 struct hlist_nulls_head *head = select_bucket(htab, i);
1129 struct hlist_nulls_node *n;
1130 struct htab_elem *l;
1132 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1133 hlist_nulls_del_rcu(&l->hash_node);
1134 htab_elem_free(htab, l);
1139 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1140 static void htab_map_free(struct bpf_map *map)
1142 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1144 /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
1145 * so the programs (can be more than one that used this map) were
1146 * disconnected from events. Wait for outstanding critical sections in
1147 * these programs to complete
1151 /* some of free_htab_elem() callbacks for elements of this map may
1152 * not have executed. Wait for them.
1155 if (!htab_is_prealloc(htab))
1156 delete_all_elements(htab);
1158 prealloc_destroy(htab);
1160 free_percpu(htab->extra_elems);
1161 bpf_map_area_free(htab->buckets);
1165 const struct bpf_map_ops htab_map_ops = {
1166 .map_alloc_check = htab_map_alloc_check,
1167 .map_alloc = htab_map_alloc,
1168 .map_free = htab_map_free,
1169 .map_get_next_key = htab_map_get_next_key,
1170 .map_lookup_elem = htab_map_lookup_elem,
1171 .map_update_elem = htab_map_update_elem,
1172 .map_delete_elem = htab_map_delete_elem,
1173 .map_gen_lookup = htab_map_gen_lookup,
1176 const struct bpf_map_ops htab_lru_map_ops = {
1177 .map_alloc_check = htab_map_alloc_check,
1178 .map_alloc = htab_map_alloc,
1179 .map_free = htab_map_free,
1180 .map_get_next_key = htab_map_get_next_key,
1181 .map_lookup_elem = htab_lru_map_lookup_elem,
1182 .map_update_elem = htab_lru_map_update_elem,
1183 .map_delete_elem = htab_lru_map_delete_elem,
1184 .map_gen_lookup = htab_lru_map_gen_lookup,
1187 /* Called from eBPF program */
1188 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1190 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1193 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1198 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1200 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1203 bpf_lru_node_set_ref(&l->lru_node);
1204 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1210 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1212 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1213 struct htab_elem *l;
1214 void __percpu *pptr;
1219 /* per_cpu areas are zero-filled and bpf programs can only
1220 * access 'value_size' of them, so copying rounded areas
1221 * will not leak any kernel data
1223 size = round_up(map->value_size, 8);
1225 l = __htab_map_lookup_elem(map, key);
1228 if (htab_is_lru(htab))
1229 bpf_lru_node_set_ref(&l->lru_node);
1230 pptr = htab_elem_get_ptr(l, map->key_size);
1231 for_each_possible_cpu(cpu) {
1232 bpf_long_memcpy(value + off,
1233 per_cpu_ptr(pptr, cpu), size);
1242 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1245 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1249 if (htab_is_lru(htab))
1250 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1253 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1260 const struct bpf_map_ops htab_percpu_map_ops = {
1261 .map_alloc_check = htab_map_alloc_check,
1262 .map_alloc = htab_map_alloc,
1263 .map_free = htab_map_free,
1264 .map_get_next_key = htab_map_get_next_key,
1265 .map_lookup_elem = htab_percpu_map_lookup_elem,
1266 .map_update_elem = htab_percpu_map_update_elem,
1267 .map_delete_elem = htab_map_delete_elem,
1270 const struct bpf_map_ops htab_lru_percpu_map_ops = {
1271 .map_alloc_check = htab_map_alloc_check,
1272 .map_alloc = htab_map_alloc,
1273 .map_free = htab_map_free,
1274 .map_get_next_key = htab_map_get_next_key,
1275 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
1276 .map_update_elem = htab_lru_percpu_map_update_elem,
1277 .map_delete_elem = htab_lru_map_delete_elem,
1280 static int fd_htab_map_alloc_check(union bpf_attr *attr)
1282 if (attr->value_size != sizeof(u32))
1284 return htab_map_alloc_check(attr);
1287 static void fd_htab_map_free(struct bpf_map *map)
1289 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1290 struct hlist_nulls_node *n;
1291 struct hlist_nulls_head *head;
1292 struct htab_elem *l;
1295 for (i = 0; i < htab->n_buckets; i++) {
1296 head = select_bucket(htab, i);
1298 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1299 void *ptr = fd_htab_map_get_ptr(map, l);
1301 map->ops->map_fd_put_ptr(ptr);
1308 /* only called from syscall */
1309 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
1314 if (!map->ops->map_fd_sys_lookup_elem)
1318 ptr = htab_map_lookup_elem(map, key);
1320 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
1328 /* only called from syscall */
1329 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
1330 void *key, void *value, u64 map_flags)
1334 u32 ufd = *(u32 *)value;
1336 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
1338 return PTR_ERR(ptr);
1340 ret = htab_map_update_elem(map, key, &ptr, map_flags);
1342 map->ops->map_fd_put_ptr(ptr);
1347 static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
1349 struct bpf_map *map, *inner_map_meta;
1351 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1352 if (IS_ERR(inner_map_meta))
1353 return inner_map_meta;
1355 map = htab_map_alloc(attr);
1357 bpf_map_meta_free(inner_map_meta);
1361 map->inner_map_meta = inner_map_meta;
1366 static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
1368 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
1373 return READ_ONCE(*inner_map);
1376 static u32 htab_of_map_gen_lookup(struct bpf_map *map,
1377 struct bpf_insn *insn_buf)
1379 struct bpf_insn *insn = insn_buf;
1380 const int ret = BPF_REG_0;
1382 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
1383 (void *(*)(struct bpf_map *map, void *key))NULL));
1384 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
1385 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
1386 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
1387 offsetof(struct htab_elem, key) +
1388 round_up(map->key_size, 8));
1389 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1391 return insn - insn_buf;
1394 static void htab_of_map_free(struct bpf_map *map)
1396 bpf_map_meta_free(map->inner_map_meta);
1397 fd_htab_map_free(map);
1400 const struct bpf_map_ops htab_of_maps_map_ops = {
1401 .map_alloc_check = fd_htab_map_alloc_check,
1402 .map_alloc = htab_of_map_alloc,
1403 .map_free = htab_of_map_free,
1404 .map_get_next_key = htab_map_get_next_key,
1405 .map_lookup_elem = htab_of_map_lookup_elem,
1406 .map_delete_elem = htab_map_delete_elem,
1407 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1408 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1409 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1410 .map_gen_lookup = htab_of_map_gen_lookup,