1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
7 #include <linux/jhash.h>
8 #include <linux/filter.h>
9 #include <linux/rculist_nulls.h>
10 #include <linux/random.h>
11 #include <uapi/linux/btf.h>
12 #include "percpu_freelist.h"
13 #include "bpf_lru_list.h"
14 #include "map_in_map.h"
16 #define HTAB_CREATE_FLAG_MASK \
17 (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
18 BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
20 #define BATCH_OPS(_name) \
22 _name##_map_lookup_batch, \
23 .map_lookup_and_delete_batch = \
24 _name##_map_lookup_and_delete_batch, \
26 generic_map_update_batch, \
28 generic_map_delete_batch
31 * The bucket lock has two protection scopes:
33 * 1) Serializing concurrent operations from BPF programs on differrent
36 * 2) Serializing concurrent operations from BPF programs and sys_bpf()
38 * BPF programs can execute in any context including perf, kprobes and
39 * tracing. As there are almost no limits where perf, kprobes and tracing
40 * can be invoked from the lock operations need to be protected against
41 * deadlocks. Deadlocks can be caused by recursion and by an invocation in
42 * the lock held section when functions which acquire this lock are invoked
43 * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
44 * variable bpf_prog_active, which prevents BPF programs attached to perf
45 * events, kprobes and tracing to be invoked before the prior invocation
46 * from one of these contexts completed. sys_bpf() uses the same mechanism
47 * by pinning the task to the current CPU and incrementing the recursion
48 * protection accross the map operation.
50 * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
51 * operations like memory allocations (even with GFP_ATOMIC) from atomic
52 * contexts. This is required because even with GFP_ATOMIC the memory
53 * allocator calls into code pathes which acquire locks with long held lock
54 * sections. To ensure the deterministic behaviour these locks are regular
55 * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
56 * true atomic contexts on an RT kernel are the low level hardware
57 * handling, scheduling, low level interrupt handling, NMIs etc. None of
58 * these contexts should ever do memory allocations.
60 * As regular device interrupt handlers and soft interrupts are forced into
61 * thread context, the existing code which does
62 * spin_lock*(); alloc(GPF_ATOMIC); spin_unlock*();
65 * In theory the BPF locks could be converted to regular spinlocks as well,
66 * but the bucket locks and percpu_freelist locks can be taken from
67 * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
68 * atomic contexts even on RT. These mechanisms require preallocated maps,
69 * so there is no need to invoke memory allocations within the lock held
72 * BPF maps which need dynamic allocation are only used from (forced)
73 * thread context on RT and can therefore use regular spinlocks which in
74 * turn allows to invoke memory allocations from the lock held section.
76 * On a non RT kernel this distinction is neither possible nor required.
77 * spinlock maps to raw_spinlock and the extra code is optimized out by the
81 struct hlist_nulls_head head;
83 raw_spinlock_t raw_lock;
90 struct bucket *buckets;
93 struct pcpu_freelist freelist;
96 struct htab_elem *__percpu *extra_elems;
97 atomic_t count; /* number of elements in this hashtable */
98 u32 n_buckets; /* number of hash buckets */
99 u32 elem_size; /* size of each element in bytes */
103 /* each htab element is struct htab_elem + key + value */
106 struct hlist_nulls_node hash_node;
110 struct bpf_htab *htab;
111 struct pcpu_freelist_node fnode;
112 struct htab_elem *batch_flink;
118 struct bpf_lru_node lru_node;
121 char key[] __aligned(8);
124 static inline bool htab_is_prealloc(const struct bpf_htab *htab)
126 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
129 static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
131 return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
134 static void htab_init_buckets(struct bpf_htab *htab)
138 for (i = 0; i < htab->n_buckets; i++) {
139 INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
140 if (htab_use_raw_lock(htab))
141 raw_spin_lock_init(&htab->buckets[i].raw_lock);
143 spin_lock_init(&htab->buckets[i].lock);
147 static inline unsigned long htab_lock_bucket(const struct bpf_htab *htab,
152 if (htab_use_raw_lock(htab))
153 raw_spin_lock_irqsave(&b->raw_lock, flags);
155 spin_lock_irqsave(&b->lock, flags);
159 static inline void htab_unlock_bucket(const struct bpf_htab *htab,
163 if (htab_use_raw_lock(htab))
164 raw_spin_unlock_irqrestore(&b->raw_lock, flags);
166 spin_unlock_irqrestore(&b->lock, flags);
169 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
171 static bool htab_is_lru(const struct bpf_htab *htab)
173 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
174 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
177 static bool htab_is_percpu(const struct bpf_htab *htab)
179 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
180 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
183 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
186 *(void __percpu **)(l->key + key_size) = pptr;
189 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
191 return *(void __percpu **)(l->key + key_size);
194 static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
196 return *(void **)(l->key + roundup(map->key_size, 8));
199 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
201 return (struct htab_elem *) (htab->elems + i * htab->elem_size);
204 static void htab_free_elems(struct bpf_htab *htab)
208 if (!htab_is_percpu(htab))
211 for (i = 0; i < htab->map.max_entries; i++) {
214 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
220 bpf_map_area_free(htab->elems);
223 /* The LRU list has a lock (lru_lock). Each htab bucket has a lock
224 * (bucket_lock). If both locks need to be acquired together, the lock
225 * order is always lru_lock -> bucket_lock and this only happens in
226 * bpf_lru_list.c logic. For example, certain code path of
227 * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
228 * will acquire lru_lock first followed by acquiring bucket_lock.
230 * In hashtab.c, to avoid deadlock, lock acquisition of
231 * bucket_lock followed by lru_lock is not allowed. In such cases,
232 * bucket_lock needs to be released first before acquiring lru_lock.
234 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
237 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
241 l = container_of(node, struct htab_elem, lru_node);
242 memcpy(l->key, key, htab->map.key_size);
249 static int prealloc_init(struct bpf_htab *htab)
251 u32 num_entries = htab->map.max_entries;
252 int err = -ENOMEM, i;
254 if (!htab_is_percpu(htab) && !htab_is_lru(htab))
255 num_entries += num_possible_cpus();
257 htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
258 htab->map.numa_node);
262 if (!htab_is_percpu(htab))
263 goto skip_percpu_elems;
265 for (i = 0; i < num_entries; i++) {
266 u32 size = round_up(htab->map.value_size, 8);
269 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
272 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
278 if (htab_is_lru(htab))
279 err = bpf_lru_init(&htab->lru,
280 htab->map.map_flags & BPF_F_NO_COMMON_LRU,
281 offsetof(struct htab_elem, hash) -
282 offsetof(struct htab_elem, lru_node),
283 htab_lru_map_delete_node,
286 err = pcpu_freelist_init(&htab->freelist);
291 if (htab_is_lru(htab))
292 bpf_lru_populate(&htab->lru, htab->elems,
293 offsetof(struct htab_elem, lru_node),
294 htab->elem_size, num_entries);
296 pcpu_freelist_populate(&htab->freelist,
297 htab->elems + offsetof(struct htab_elem, fnode),
298 htab->elem_size, num_entries);
303 htab_free_elems(htab);
307 static void prealloc_destroy(struct bpf_htab *htab)
309 htab_free_elems(htab);
311 if (htab_is_lru(htab))
312 bpf_lru_destroy(&htab->lru);
314 pcpu_freelist_destroy(&htab->freelist);
317 static int alloc_extra_elems(struct bpf_htab *htab)
319 struct htab_elem *__percpu *pptr, *l_new;
320 struct pcpu_freelist_node *l;
323 pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
324 GFP_USER | __GFP_NOWARN);
328 for_each_possible_cpu(cpu) {
329 l = pcpu_freelist_pop(&htab->freelist);
330 /* pop will succeed, since prealloc_init()
331 * preallocated extra num_possible_cpus elements
333 l_new = container_of(l, struct htab_elem, fnode);
334 *per_cpu_ptr(pptr, cpu) = l_new;
336 htab->extra_elems = pptr;
340 /* Called from syscall */
341 static int htab_map_alloc_check(union bpf_attr *attr)
343 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
344 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
345 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
346 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
347 /* percpu_lru means each cpu has its own LRU list.
348 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
349 * the map's value itself is percpu. percpu_lru has
350 * nothing to do with the map's value.
352 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
353 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
354 bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
355 int numa_node = bpf_map_attr_numa_node(attr);
357 BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
358 offsetof(struct htab_elem, hash_node.pprev));
359 BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
360 offsetof(struct htab_elem, hash_node.pprev));
362 if (lru && !bpf_capable())
363 /* LRU implementation is much complicated than other
364 * maps. Hence, limit to CAP_BPF.
368 if (zero_seed && !capable(CAP_SYS_ADMIN))
369 /* Guard against local DoS, and discourage production use. */
372 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
373 !bpf_map_flags_access_ok(attr->map_flags))
376 if (!lru && percpu_lru)
379 if (lru && !prealloc)
382 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
385 /* check sanity of attributes.
386 * value_size == 0 may be allowed in the future to use map as a set
388 if (attr->max_entries == 0 || attr->key_size == 0 ||
389 attr->value_size == 0)
392 if (attr->key_size > MAX_BPF_STACK)
393 /* eBPF programs initialize keys on stack, so they cannot be
394 * larger than max stack size
398 if (attr->value_size >= KMALLOC_MAX_SIZE -
399 MAX_BPF_STACK - sizeof(struct htab_elem))
400 /* if value_size is bigger, the user space won't be able to
401 * access the elements via bpf syscall. This check also makes
402 * sure that the elem_size doesn't overflow and it's
403 * kmalloc-able later in htab_map_update_elem()
410 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
412 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
413 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
414 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
415 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
416 /* percpu_lru means each cpu has its own LRU list.
417 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
418 * the map's value itself is percpu. percpu_lru has
419 * nothing to do with the map's value.
421 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
422 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
423 struct bpf_htab *htab;
427 htab = kzalloc(sizeof(*htab), GFP_USER);
429 return ERR_PTR(-ENOMEM);
431 bpf_map_init_from_attr(&htab->map, attr);
434 /* ensure each CPU's lru list has >=1 elements.
435 * since we are at it, make each lru list has the same
436 * number of elements.
438 htab->map.max_entries = roundup(attr->max_entries,
439 num_possible_cpus());
440 if (htab->map.max_entries < attr->max_entries)
441 htab->map.max_entries = rounddown(attr->max_entries,
442 num_possible_cpus());
445 /* hash table size must be power of 2 */
446 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
448 htab->elem_size = sizeof(struct htab_elem) +
449 round_up(htab->map.key_size, 8);
451 htab->elem_size += sizeof(void *);
453 htab->elem_size += round_up(htab->map.value_size, 8);
456 /* prevent zero size kmalloc and check for u32 overflow */
457 if (htab->n_buckets == 0 ||
458 htab->n_buckets > U32_MAX / sizeof(struct bucket))
461 cost = (u64) htab->n_buckets * sizeof(struct bucket) +
462 (u64) htab->elem_size * htab->map.max_entries;
465 cost += (u64) round_up(htab->map.value_size, 8) *
466 num_possible_cpus() * htab->map.max_entries;
468 cost += (u64) htab->elem_size * num_possible_cpus();
470 /* if map size is larger than memlock limit, reject it */
471 err = bpf_map_charge_init(&htab->map.memory, cost);
476 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
477 sizeof(struct bucket),
478 htab->map.numa_node);
482 if (htab->map.map_flags & BPF_F_ZERO_SEED)
485 htab->hashrnd = get_random_int();
487 htab_init_buckets(htab);
490 err = prealloc_init(htab);
494 if (!percpu && !lru) {
495 /* lru itself can remove the least used element, so
496 * there is no need for an extra elem during map_update.
498 err = alloc_extra_elems(htab);
507 prealloc_destroy(htab);
509 bpf_map_area_free(htab->buckets);
511 bpf_map_charge_finish(&htab->map.memory);
517 static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
519 return jhash(key, key_len, hashrnd);
522 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
524 return &htab->buckets[hash & (htab->n_buckets - 1)];
527 static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
529 return &__select_bucket(htab, hash)->head;
532 /* this lookup function can only be called with bucket lock taken */
533 static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
534 void *key, u32 key_size)
536 struct hlist_nulls_node *n;
539 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
540 if (l->hash == hash && !memcmp(&l->key, key, key_size))
546 /* can be called without bucket lock. it will repeat the loop in
547 * the unlikely event when elements moved from one bucket into another
548 * while link list is being walked
550 static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
552 u32 key_size, u32 n_buckets)
554 struct hlist_nulls_node *n;
558 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
559 if (l->hash == hash && !memcmp(&l->key, key, key_size))
562 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
568 /* Called from syscall or from eBPF program directly, so
569 * arguments have to match bpf_map_lookup_elem() exactly.
570 * The return value is adjusted by BPF instructions
571 * in htab_map_gen_lookup().
573 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
575 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
576 struct hlist_nulls_head *head;
580 /* Must be called with rcu_read_lock. */
581 WARN_ON_ONCE(!rcu_read_lock_held());
583 key_size = map->key_size;
585 hash = htab_map_hash(key, key_size, htab->hashrnd);
587 head = select_bucket(htab, hash);
589 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
594 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
596 struct htab_elem *l = __htab_map_lookup_elem(map, key);
599 return l->key + round_up(map->key_size, 8);
604 /* inline bpf_map_lookup_elem() call.
607 * bpf_map_lookup_elem
608 * map->ops->map_lookup_elem
609 * htab_map_lookup_elem
610 * __htab_map_lookup_elem
613 * __htab_map_lookup_elem
615 static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
617 struct bpf_insn *insn = insn_buf;
618 const int ret = BPF_REG_0;
620 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
621 (void *(*)(struct bpf_map *map, void *key))NULL));
622 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
623 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
624 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
625 offsetof(struct htab_elem, key) +
626 round_up(map->key_size, 8));
627 return insn - insn_buf;
630 static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
631 void *key, const bool mark)
633 struct htab_elem *l = __htab_map_lookup_elem(map, key);
637 bpf_lru_node_set_ref(&l->lru_node);
638 return l->key + round_up(map->key_size, 8);
644 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
646 return __htab_lru_map_lookup_elem(map, key, true);
649 static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
651 return __htab_lru_map_lookup_elem(map, key, false);
654 static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
655 struct bpf_insn *insn_buf)
657 struct bpf_insn *insn = insn_buf;
658 const int ret = BPF_REG_0;
659 const int ref_reg = BPF_REG_1;
661 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
662 (void *(*)(struct bpf_map *map, void *key))NULL));
663 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
664 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
665 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
666 offsetof(struct htab_elem, lru_node) +
667 offsetof(struct bpf_lru_node, ref));
668 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
669 *insn++ = BPF_ST_MEM(BPF_B, ret,
670 offsetof(struct htab_elem, lru_node) +
671 offsetof(struct bpf_lru_node, ref),
673 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
674 offsetof(struct htab_elem, key) +
675 round_up(map->key_size, 8));
676 return insn - insn_buf;
679 /* It is called from the bpf_lru_list when the LRU needs to delete
680 * older elements from the htab.
682 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
684 struct bpf_htab *htab = (struct bpf_htab *)arg;
685 struct htab_elem *l = NULL, *tgt_l;
686 struct hlist_nulls_head *head;
687 struct hlist_nulls_node *n;
691 tgt_l = container_of(node, struct htab_elem, lru_node);
692 b = __select_bucket(htab, tgt_l->hash);
695 flags = htab_lock_bucket(htab, b);
697 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
699 hlist_nulls_del_rcu(&l->hash_node);
703 htab_unlock_bucket(htab, b, flags);
708 /* Called from syscall */
709 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
711 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
712 struct hlist_nulls_head *head;
713 struct htab_elem *l, *next_l;
717 WARN_ON_ONCE(!rcu_read_lock_held());
719 key_size = map->key_size;
722 goto find_first_elem;
724 hash = htab_map_hash(key, key_size, htab->hashrnd);
726 head = select_bucket(htab, hash);
729 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
732 goto find_first_elem;
734 /* key was found, get next key in the same bucket */
735 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
736 struct htab_elem, hash_node);
739 /* if next elem in this hash list is non-zero, just return it */
740 memcpy(next_key, next_l->key, key_size);
744 /* no more elements in this hash list, go to the next bucket */
745 i = hash & (htab->n_buckets - 1);
749 /* iterate over buckets */
750 for (; i < htab->n_buckets; i++) {
751 head = select_bucket(htab, i);
753 /* pick first element in the bucket */
754 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
755 struct htab_elem, hash_node);
757 /* if it's not empty, just return it */
758 memcpy(next_key, next_l->key, key_size);
763 /* iterated over all buckets and all elements */
767 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
769 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
770 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
774 static void htab_elem_free_rcu(struct rcu_head *head)
776 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
777 struct bpf_htab *htab = l->htab;
779 htab_elem_free(htab, l);
782 static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
784 struct bpf_map *map = &htab->map;
787 if (map->ops->map_fd_put_ptr) {
788 ptr = fd_htab_map_get_ptr(map, l);
789 map->ops->map_fd_put_ptr(ptr);
793 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
795 htab_put_fd_value(htab, l);
797 if (htab_is_prealloc(htab)) {
798 __pcpu_freelist_push(&htab->freelist, &l->fnode);
800 atomic_dec(&htab->count);
802 call_rcu(&l->rcu, htab_elem_free_rcu);
806 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
807 void *value, bool onallcpus)
810 /* copy true value_size bytes */
811 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
813 u32 size = round_up(htab->map.value_size, 8);
816 for_each_possible_cpu(cpu) {
817 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
824 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
826 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
830 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
831 void *value, u32 key_size, u32 hash,
832 bool percpu, bool onallcpus,
833 struct htab_elem *old_elem)
835 u32 size = htab->map.value_size;
836 bool prealloc = htab_is_prealloc(htab);
837 struct htab_elem *l_new, **pl_new;
842 /* if we're updating the existing element,
843 * use per-cpu extra elems to avoid freelist_pop/push
845 pl_new = this_cpu_ptr(htab->extra_elems);
847 htab_put_fd_value(htab, old_elem);
850 struct pcpu_freelist_node *l;
852 l = __pcpu_freelist_pop(&htab->freelist);
854 return ERR_PTR(-E2BIG);
855 l_new = container_of(l, struct htab_elem, fnode);
858 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
860 /* when map is full and update() is replacing
861 * old element, it's ok to allocate, since
862 * old element will be freed immediately.
863 * Otherwise return an error
865 l_new = ERR_PTR(-E2BIG);
868 l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
869 htab->map.numa_node);
871 l_new = ERR_PTR(-ENOMEM);
874 check_and_init_map_lock(&htab->map,
875 l_new->key + round_up(key_size, 8));
878 memcpy(l_new->key, key, key_size);
880 size = round_up(size, 8);
882 pptr = htab_elem_get_ptr(l_new, key_size);
884 /* alloc_percpu zero-fills */
885 pptr = __alloc_percpu_gfp(size, 8,
886 GFP_ATOMIC | __GFP_NOWARN);
889 l_new = ERR_PTR(-ENOMEM);
894 pcpu_copy_value(htab, pptr, value, onallcpus);
897 htab_elem_set_ptr(l_new, key_size, pptr);
898 } else if (fd_htab_map_needs_adjust(htab)) {
899 size = round_up(size, 8);
900 memcpy(l_new->key + round_up(key_size, 8), value, size);
902 copy_map_value(&htab->map,
903 l_new->key + round_up(key_size, 8),
910 atomic_dec(&htab->count);
914 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
917 if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
918 /* elem already exists */
921 if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
922 /* elem doesn't exist, cannot update it */
928 /* Called from syscall or from eBPF program */
929 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
932 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
933 struct htab_elem *l_new = NULL, *l_old;
934 struct hlist_nulls_head *head;
940 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
944 WARN_ON_ONCE(!rcu_read_lock_held());
946 key_size = map->key_size;
948 hash = htab_map_hash(key, key_size, htab->hashrnd);
950 b = __select_bucket(htab, hash);
953 if (unlikely(map_flags & BPF_F_LOCK)) {
954 if (unlikely(!map_value_has_spin_lock(map)))
956 /* find an element without taking the bucket lock */
957 l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
959 ret = check_flags(htab, l_old, map_flags);
963 /* grab the element lock and update value in place */
964 copy_map_value_locked(map,
965 l_old->key + round_up(key_size, 8),
969 /* fall through, grab the bucket lock and lookup again.
970 * 99.9% chance that the element won't be found,
971 * but second lookup under lock has to be done.
975 flags = htab_lock_bucket(htab, b);
977 l_old = lookup_elem_raw(head, hash, key, key_size);
979 ret = check_flags(htab, l_old, map_flags);
983 if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
984 /* first lookup without the bucket lock didn't find the element,
985 * but second lookup with the bucket lock found it.
986 * This case is highly unlikely, but has to be dealt with:
987 * grab the element lock in addition to the bucket lock
988 * and update element in place
990 copy_map_value_locked(map,
991 l_old->key + round_up(key_size, 8),
997 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
1000 /* all pre-allocated elements are in use or memory exhausted */
1001 ret = PTR_ERR(l_new);
1005 /* add new element to the head of the list, so that
1006 * concurrent search will find it before old elem
1008 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1010 hlist_nulls_del_rcu(&l_old->hash_node);
1011 if (!htab_is_prealloc(htab))
1012 free_htab_elem(htab, l_old);
1016 htab_unlock_bucket(htab, b, flags);
1020 static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1023 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1024 struct htab_elem *l_new, *l_old = NULL;
1025 struct hlist_nulls_head *head;
1026 unsigned long flags;
1031 if (unlikely(map_flags > BPF_EXIST))
1035 WARN_ON_ONCE(!rcu_read_lock_held());
1037 key_size = map->key_size;
1039 hash = htab_map_hash(key, key_size, htab->hashrnd);
1041 b = __select_bucket(htab, hash);
1044 /* For LRU, we need to alloc before taking bucket's
1045 * spinlock because getting free nodes from LRU may need
1046 * to remove older elements from htab and this removal
1047 * operation will need a bucket lock.
1049 l_new = prealloc_lru_pop(htab, key, hash);
1052 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
1054 flags = htab_lock_bucket(htab, b);
1056 l_old = lookup_elem_raw(head, hash, key, key_size);
1058 ret = check_flags(htab, l_old, map_flags);
1062 /* add new element to the head of the list, so that
1063 * concurrent search will find it before old elem
1065 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1067 bpf_lru_node_set_ref(&l_new->lru_node);
1068 hlist_nulls_del_rcu(&l_old->hash_node);
1073 htab_unlock_bucket(htab, b, flags);
1076 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1078 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
1083 static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1084 void *value, u64 map_flags,
1087 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1088 struct htab_elem *l_new = NULL, *l_old;
1089 struct hlist_nulls_head *head;
1090 unsigned long flags;
1095 if (unlikely(map_flags > BPF_EXIST))
1099 WARN_ON_ONCE(!rcu_read_lock_held());
1101 key_size = map->key_size;
1103 hash = htab_map_hash(key, key_size, htab->hashrnd);
1105 b = __select_bucket(htab, hash);
1108 flags = htab_lock_bucket(htab, b);
1110 l_old = lookup_elem_raw(head, hash, key, key_size);
1112 ret = check_flags(htab, l_old, map_flags);
1117 /* per-cpu hash map can update value in-place */
1118 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1121 l_new = alloc_htab_elem(htab, key, value, key_size,
1122 hash, true, onallcpus, NULL);
1123 if (IS_ERR(l_new)) {
1124 ret = PTR_ERR(l_new);
1127 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1131 htab_unlock_bucket(htab, b, flags);
1135 static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1136 void *value, u64 map_flags,
1139 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1140 struct htab_elem *l_new = NULL, *l_old;
1141 struct hlist_nulls_head *head;
1142 unsigned long flags;
1147 if (unlikely(map_flags > BPF_EXIST))
1151 WARN_ON_ONCE(!rcu_read_lock_held());
1153 key_size = map->key_size;
1155 hash = htab_map_hash(key, key_size, htab->hashrnd);
1157 b = __select_bucket(htab, hash);
1160 /* For LRU, we need to alloc before taking bucket's
1161 * spinlock because LRU's elem alloc may need
1162 * to remove older elem from htab and this removal
1163 * operation will need a bucket lock.
1165 if (map_flags != BPF_EXIST) {
1166 l_new = prealloc_lru_pop(htab, key, hash);
1171 flags = htab_lock_bucket(htab, b);
1173 l_old = lookup_elem_raw(head, hash, key, key_size);
1175 ret = check_flags(htab, l_old, map_flags);
1180 bpf_lru_node_set_ref(&l_old->lru_node);
1182 /* per-cpu hash map can update value in-place */
1183 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1186 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
1188 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1193 htab_unlock_bucket(htab, b, flags);
1195 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1199 static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1200 void *value, u64 map_flags)
1202 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1205 static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1206 void *value, u64 map_flags)
1208 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1212 /* Called from syscall or from eBPF program */
1213 static int htab_map_delete_elem(struct bpf_map *map, void *key)
1215 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1216 struct hlist_nulls_head *head;
1218 struct htab_elem *l;
1219 unsigned long flags;
1223 WARN_ON_ONCE(!rcu_read_lock_held());
1225 key_size = map->key_size;
1227 hash = htab_map_hash(key, key_size, htab->hashrnd);
1228 b = __select_bucket(htab, hash);
1231 flags = htab_lock_bucket(htab, b);
1233 l = lookup_elem_raw(head, hash, key, key_size);
1236 hlist_nulls_del_rcu(&l->hash_node);
1237 free_htab_elem(htab, l);
1241 htab_unlock_bucket(htab, b, flags);
1245 static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1247 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1248 struct hlist_nulls_head *head;
1250 struct htab_elem *l;
1251 unsigned long flags;
1255 WARN_ON_ONCE(!rcu_read_lock_held());
1257 key_size = map->key_size;
1259 hash = htab_map_hash(key, key_size, htab->hashrnd);
1260 b = __select_bucket(htab, hash);
1263 flags = htab_lock_bucket(htab, b);
1265 l = lookup_elem_raw(head, hash, key, key_size);
1268 hlist_nulls_del_rcu(&l->hash_node);
1272 htab_unlock_bucket(htab, b, flags);
1274 bpf_lru_push_free(&htab->lru, &l->lru_node);
1278 static void delete_all_elements(struct bpf_htab *htab)
1282 for (i = 0; i < htab->n_buckets; i++) {
1283 struct hlist_nulls_head *head = select_bucket(htab, i);
1284 struct hlist_nulls_node *n;
1285 struct htab_elem *l;
1287 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1288 hlist_nulls_del_rcu(&l->hash_node);
1289 htab_elem_free(htab, l);
1294 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1295 static void htab_map_free(struct bpf_map *map)
1297 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1299 /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
1300 * bpf_free_used_maps() is called after bpf prog is no longer executing.
1301 * There is no need to synchronize_rcu() here to protect map elements.
1304 /* some of free_htab_elem() callbacks for elements of this map may
1305 * not have executed. Wait for them.
1308 if (!htab_is_prealloc(htab))
1309 delete_all_elements(htab);
1311 prealloc_destroy(htab);
1313 free_percpu(htab->extra_elems);
1314 bpf_map_area_free(htab->buckets);
1318 static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1325 value = htab_map_lookup_elem(map, key);
1331 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1333 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1340 __htab_map_lookup_and_delete_batch(struct bpf_map *map,
1341 const union bpf_attr *attr,
1342 union bpf_attr __user *uattr,
1343 bool do_delete, bool is_lru_map,
1346 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1347 u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
1348 void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
1349 void __user *uvalues = u64_to_user_ptr(attr->batch.values);
1350 void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
1351 void *ubatch = u64_to_user_ptr(attr->batch.in_batch);
1352 u32 batch, max_count, size, bucket_size;
1353 struct htab_elem *node_to_free = NULL;
1354 u64 elem_map_flags, map_flags;
1355 struct hlist_nulls_head *head;
1356 struct hlist_nulls_node *n;
1357 unsigned long flags = 0;
1358 bool locked = false;
1359 struct htab_elem *l;
1363 elem_map_flags = attr->batch.elem_flags;
1364 if ((elem_map_flags & ~BPF_F_LOCK) ||
1365 ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
1368 map_flags = attr->batch.flags;
1372 max_count = attr->batch.count;
1376 if (put_user(0, &uattr->batch.count))
1380 if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1383 if (batch >= htab->n_buckets)
1386 key_size = htab->map.key_size;
1387 roundup_key_size = round_up(htab->map.key_size, 8);
1388 value_size = htab->map.value_size;
1389 size = round_up(value_size, 8);
1391 value_size = size * num_possible_cpus();
1393 /* while experimenting with hash tables with sizes ranging from 10 to
1394 * 1000, it was observed that a bucket can have upto 5 entries.
1399 /* We cannot do copy_from_user or copy_to_user inside
1400 * the rcu_read_lock. Allocate enough space here.
1402 keys = kvmalloc(key_size * bucket_size, GFP_USER | __GFP_NOWARN);
1403 values = kvmalloc(value_size * bucket_size, GFP_USER | __GFP_NOWARN);
1404 if (!keys || !values) {
1410 bpf_disable_instrumentation();
1415 b = &htab->buckets[batch];
1417 /* do not grab the lock unless need it (bucket_cnt > 0). */
1419 flags = htab_lock_bucket(htab, b);
1422 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1425 if (bucket_cnt && !locked) {
1430 if (bucket_cnt > (max_count - total)) {
1433 /* Note that since bucket_cnt > 0 here, it is implicit
1434 * that the locked was grabbed, so release it.
1436 htab_unlock_bucket(htab, b, flags);
1438 bpf_enable_instrumentation();
1442 if (bucket_cnt > bucket_size) {
1443 bucket_size = bucket_cnt;
1444 /* Note that since bucket_cnt > 0 here, it is implicit
1445 * that the locked was grabbed, so release it.
1447 htab_unlock_bucket(htab, b, flags);
1449 bpf_enable_instrumentation();
1455 /* Next block is only safe to run if you have grabbed the lock */
1459 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1460 memcpy(dst_key, l->key, key_size);
1464 void __percpu *pptr;
1466 pptr = htab_elem_get_ptr(l, map->key_size);
1467 for_each_possible_cpu(cpu) {
1468 bpf_long_memcpy(dst_val + off,
1469 per_cpu_ptr(pptr, cpu), size);
1473 value = l->key + roundup_key_size;
1474 if (elem_map_flags & BPF_F_LOCK)
1475 copy_map_value_locked(map, dst_val, value,
1478 copy_map_value(map, dst_val, value);
1479 check_and_init_map_lock(map, dst_val);
1482 hlist_nulls_del_rcu(&l->hash_node);
1484 /* bpf_lru_push_free() will acquire lru_lock, which
1485 * may cause deadlock. See comments in function
1486 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
1487 * after releasing the bucket lock.
1490 l->batch_flink = node_to_free;
1493 free_htab_elem(htab, l);
1496 dst_key += key_size;
1497 dst_val += value_size;
1500 htab_unlock_bucket(htab, b, flags);
1503 while (node_to_free) {
1505 node_to_free = node_to_free->batch_flink;
1506 bpf_lru_push_free(&htab->lru, &l->lru_node);
1510 /* If we are not copying data, we can go to next bucket and avoid
1511 * unlocking the rcu.
1513 if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1519 bpf_enable_instrumentation();
1520 if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
1521 key_size * bucket_cnt) ||
1522 copy_to_user(uvalues + total * value_size, values,
1523 value_size * bucket_cnt))) {
1528 total += bucket_cnt;
1530 if (batch >= htab->n_buckets) {
1540 /* copy # of entries and next batch */
1541 ubatch = u64_to_user_ptr(attr->batch.out_batch);
1542 if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
1543 put_user(total, &uattr->batch.count))
1553 htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1554 union bpf_attr __user *uattr)
1556 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1561 htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1562 const union bpf_attr *attr,
1563 union bpf_attr __user *uattr)
1565 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1570 htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1571 union bpf_attr __user *uattr)
1573 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1578 htab_map_lookup_and_delete_batch(struct bpf_map *map,
1579 const union bpf_attr *attr,
1580 union bpf_attr __user *uattr)
1582 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1587 htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1588 const union bpf_attr *attr,
1589 union bpf_attr __user *uattr)
1591 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1596 htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1597 const union bpf_attr *attr,
1598 union bpf_attr __user *uattr)
1600 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1605 htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1606 union bpf_attr __user *uattr)
1608 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1613 htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1614 const union bpf_attr *attr,
1615 union bpf_attr __user *uattr)
1617 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1621 struct bpf_iter_seq_hash_map_info {
1622 struct bpf_map *map;
1623 struct bpf_htab *htab;
1624 void *percpu_value_buf; // non-zero means percpu hash
1625 unsigned long flags;
1630 static struct htab_elem *
1631 bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1632 struct htab_elem *prev_elem)
1634 const struct bpf_htab *htab = info->htab;
1635 unsigned long flags = info->flags;
1636 u32 skip_elems = info->skip_elems;
1637 u32 bucket_id = info->bucket_id;
1638 struct hlist_nulls_head *head;
1639 struct hlist_nulls_node *n;
1640 struct htab_elem *elem;
1644 if (bucket_id >= htab->n_buckets)
1647 /* try to find next elem in the same bucket */
1649 /* no update/deletion on this bucket, prev_elem should be still valid
1650 * and we won't skip elements.
1652 n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
1653 elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
1657 /* not found, unlock and go to the next bucket */
1658 b = &htab->buckets[bucket_id++];
1659 htab_unlock_bucket(htab, b, flags);
1663 for (i = bucket_id; i < htab->n_buckets; i++) {
1664 b = &htab->buckets[i];
1665 flags = htab_lock_bucket(htab, b);
1669 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
1670 if (count >= skip_elems) {
1671 info->flags = flags;
1672 info->bucket_id = i;
1673 info->skip_elems = count;
1679 htab_unlock_bucket(htab, b, flags);
1683 info->bucket_id = i;
1684 info->skip_elems = 0;
1688 static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
1690 struct bpf_iter_seq_hash_map_info *info = seq->private;
1691 struct htab_elem *elem;
1693 elem = bpf_hash_map_seq_find_next(info, NULL);
1702 static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1704 struct bpf_iter_seq_hash_map_info *info = seq->private;
1708 return bpf_hash_map_seq_find_next(info, v);
1711 static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
1713 struct bpf_iter_seq_hash_map_info *info = seq->private;
1714 u32 roundup_key_size, roundup_value_size;
1715 struct bpf_iter__bpf_map_elem ctx = {};
1716 struct bpf_map *map = info->map;
1717 struct bpf_iter_meta meta;
1718 int ret = 0, off = 0, cpu;
1719 struct bpf_prog *prog;
1720 void __percpu *pptr;
1723 prog = bpf_iter_get_info(&meta, elem == NULL);
1726 ctx.map = info->map;
1728 roundup_key_size = round_up(map->key_size, 8);
1729 ctx.key = elem->key;
1730 if (!info->percpu_value_buf) {
1731 ctx.value = elem->key + roundup_key_size;
1733 roundup_value_size = round_up(map->value_size, 8);
1734 pptr = htab_elem_get_ptr(elem, map->key_size);
1735 for_each_possible_cpu(cpu) {
1736 bpf_long_memcpy(info->percpu_value_buf + off,
1737 per_cpu_ptr(pptr, cpu),
1738 roundup_value_size);
1739 off += roundup_value_size;
1741 ctx.value = info->percpu_value_buf;
1744 ret = bpf_iter_run_prog(prog, &ctx);
1750 static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
1752 return __bpf_hash_map_seq_show(seq, v);
1755 static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
1757 struct bpf_iter_seq_hash_map_info *info = seq->private;
1760 (void)__bpf_hash_map_seq_show(seq, NULL);
1762 htab_unlock_bucket(info->htab,
1763 &info->htab->buckets[info->bucket_id],
1767 static int bpf_iter_init_hash_map(void *priv_data,
1768 struct bpf_iter_aux_info *aux)
1770 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1771 struct bpf_map *map = aux->map;
1775 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
1776 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
1777 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
1778 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
1782 seq_info->percpu_value_buf = value_buf;
1785 seq_info->map = map;
1786 seq_info->htab = container_of(map, struct bpf_htab, map);
1790 static void bpf_iter_fini_hash_map(void *priv_data)
1792 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1794 kfree(seq_info->percpu_value_buf);
1797 static const struct seq_operations bpf_hash_map_seq_ops = {
1798 .start = bpf_hash_map_seq_start,
1799 .next = bpf_hash_map_seq_next,
1800 .stop = bpf_hash_map_seq_stop,
1801 .show = bpf_hash_map_seq_show,
1804 static const struct bpf_iter_seq_info iter_seq_info = {
1805 .seq_ops = &bpf_hash_map_seq_ops,
1806 .init_seq_private = bpf_iter_init_hash_map,
1807 .fini_seq_private = bpf_iter_fini_hash_map,
1808 .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
1811 static int htab_map_btf_id;
1812 const struct bpf_map_ops htab_map_ops = {
1813 .map_alloc_check = htab_map_alloc_check,
1814 .map_alloc = htab_map_alloc,
1815 .map_free = htab_map_free,
1816 .map_get_next_key = htab_map_get_next_key,
1817 .map_lookup_elem = htab_map_lookup_elem,
1818 .map_update_elem = htab_map_update_elem,
1819 .map_delete_elem = htab_map_delete_elem,
1820 .map_gen_lookup = htab_map_gen_lookup,
1821 .map_seq_show_elem = htab_map_seq_show_elem,
1823 .map_btf_name = "bpf_htab",
1824 .map_btf_id = &htab_map_btf_id,
1825 .iter_seq_info = &iter_seq_info,
1828 static int htab_lru_map_btf_id;
1829 const struct bpf_map_ops htab_lru_map_ops = {
1830 .map_alloc_check = htab_map_alloc_check,
1831 .map_alloc = htab_map_alloc,
1832 .map_free = htab_map_free,
1833 .map_get_next_key = htab_map_get_next_key,
1834 .map_lookup_elem = htab_lru_map_lookup_elem,
1835 .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
1836 .map_update_elem = htab_lru_map_update_elem,
1837 .map_delete_elem = htab_lru_map_delete_elem,
1838 .map_gen_lookup = htab_lru_map_gen_lookup,
1839 .map_seq_show_elem = htab_map_seq_show_elem,
1840 BATCH_OPS(htab_lru),
1841 .map_btf_name = "bpf_htab",
1842 .map_btf_id = &htab_lru_map_btf_id,
1843 .iter_seq_info = &iter_seq_info,
1846 /* Called from eBPF program */
1847 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1849 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1852 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1857 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1859 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1862 bpf_lru_node_set_ref(&l->lru_node);
1863 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1869 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1871 struct htab_elem *l;
1872 void __percpu *pptr;
1877 /* per_cpu areas are zero-filled and bpf programs can only
1878 * access 'value_size' of them, so copying rounded areas
1879 * will not leak any kernel data
1881 size = round_up(map->value_size, 8);
1883 l = __htab_map_lookup_elem(map, key);
1886 /* We do not mark LRU map element here in order to not mess up
1887 * eviction heuristics when user space does a map walk.
1889 pptr = htab_elem_get_ptr(l, map->key_size);
1890 for_each_possible_cpu(cpu) {
1891 bpf_long_memcpy(value + off,
1892 per_cpu_ptr(pptr, cpu), size);
1901 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1904 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1908 if (htab_is_lru(htab))
1909 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1912 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1919 static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
1922 struct htab_elem *l;
1923 void __percpu *pptr;
1928 l = __htab_map_lookup_elem(map, key);
1934 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1935 seq_puts(m, ": {\n");
1936 pptr = htab_elem_get_ptr(l, map->key_size);
1937 for_each_possible_cpu(cpu) {
1938 seq_printf(m, "\tcpu%d: ", cpu);
1939 btf_type_seq_show(map->btf, map->btf_value_type_id,
1940 per_cpu_ptr(pptr, cpu), m);
1948 static int htab_percpu_map_btf_id;
1949 const struct bpf_map_ops htab_percpu_map_ops = {
1950 .map_alloc_check = htab_map_alloc_check,
1951 .map_alloc = htab_map_alloc,
1952 .map_free = htab_map_free,
1953 .map_get_next_key = htab_map_get_next_key,
1954 .map_lookup_elem = htab_percpu_map_lookup_elem,
1955 .map_update_elem = htab_percpu_map_update_elem,
1956 .map_delete_elem = htab_map_delete_elem,
1957 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
1958 BATCH_OPS(htab_percpu),
1959 .map_btf_name = "bpf_htab",
1960 .map_btf_id = &htab_percpu_map_btf_id,
1961 .iter_seq_info = &iter_seq_info,
1964 static int htab_lru_percpu_map_btf_id;
1965 const struct bpf_map_ops htab_lru_percpu_map_ops = {
1966 .map_alloc_check = htab_map_alloc_check,
1967 .map_alloc = htab_map_alloc,
1968 .map_free = htab_map_free,
1969 .map_get_next_key = htab_map_get_next_key,
1970 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
1971 .map_update_elem = htab_lru_percpu_map_update_elem,
1972 .map_delete_elem = htab_lru_map_delete_elem,
1973 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
1974 BATCH_OPS(htab_lru_percpu),
1975 .map_btf_name = "bpf_htab",
1976 .map_btf_id = &htab_lru_percpu_map_btf_id,
1977 .iter_seq_info = &iter_seq_info,
1980 static int fd_htab_map_alloc_check(union bpf_attr *attr)
1982 if (attr->value_size != sizeof(u32))
1984 return htab_map_alloc_check(attr);
1987 static void fd_htab_map_free(struct bpf_map *map)
1989 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1990 struct hlist_nulls_node *n;
1991 struct hlist_nulls_head *head;
1992 struct htab_elem *l;
1995 for (i = 0; i < htab->n_buckets; i++) {
1996 head = select_bucket(htab, i);
1998 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1999 void *ptr = fd_htab_map_get_ptr(map, l);
2001 map->ops->map_fd_put_ptr(ptr);
2008 /* only called from syscall */
2009 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2014 if (!map->ops->map_fd_sys_lookup_elem)
2018 ptr = htab_map_lookup_elem(map, key);
2020 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2028 /* only called from syscall */
2029 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2030 void *key, void *value, u64 map_flags)
2034 u32 ufd = *(u32 *)value;
2036 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2038 return PTR_ERR(ptr);
2040 ret = htab_map_update_elem(map, key, &ptr, map_flags);
2042 map->ops->map_fd_put_ptr(ptr);
2047 static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2049 struct bpf_map *map, *inner_map_meta;
2051 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2052 if (IS_ERR(inner_map_meta))
2053 return inner_map_meta;
2055 map = htab_map_alloc(attr);
2057 bpf_map_meta_free(inner_map_meta);
2061 map->inner_map_meta = inner_map_meta;
2066 static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2068 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
2073 return READ_ONCE(*inner_map);
2076 static u32 htab_of_map_gen_lookup(struct bpf_map *map,
2077 struct bpf_insn *insn_buf)
2079 struct bpf_insn *insn = insn_buf;
2080 const int ret = BPF_REG_0;
2082 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2083 (void *(*)(struct bpf_map *map, void *key))NULL));
2084 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
2085 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2086 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2087 offsetof(struct htab_elem, key) +
2088 round_up(map->key_size, 8));
2089 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2091 return insn - insn_buf;
2094 static void htab_of_map_free(struct bpf_map *map)
2096 bpf_map_meta_free(map->inner_map_meta);
2097 fd_htab_map_free(map);
2100 static int htab_of_maps_map_btf_id;
2101 const struct bpf_map_ops htab_of_maps_map_ops = {
2102 .map_alloc_check = fd_htab_map_alloc_check,
2103 .map_alloc = htab_of_map_alloc,
2104 .map_free = htab_of_map_free,
2105 .map_get_next_key = htab_map_get_next_key,
2106 .map_lookup_elem = htab_of_map_lookup_elem,
2107 .map_delete_elem = htab_map_delete_elem,
2108 .map_fd_get_ptr = bpf_map_fd_get_ptr,
2109 .map_fd_put_ptr = bpf_map_fd_put_ptr,
2110 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2111 .map_gen_lookup = htab_of_map_gen_lookup,
2112 .map_check_btf = map_check_no_btf,
2113 .map_btf_name = "bpf_htab",
2114 .map_btf_id = &htab_of_maps_map_btf_id,