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1/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
3 *
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.
7 *
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.
12 */
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"
20
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)
24
25struct bucket {
26 struct hlist_nulls_head head;
27 raw_spinlock_t lock;
28};
29
30struct bpf_htab {
31 struct bpf_map map;
32 struct bucket *buckets;
33 void *elems;
34 union {
35 struct pcpu_freelist freelist;
36 struct bpf_lru lru;
37 };
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 */
42};
43
44/* each htab element is struct htab_elem + key + value */
45struct htab_elem {
46 union {
47 struct hlist_nulls_node hash_node;
48 struct {
49 void *padding;
50 union {
51 struct bpf_htab *htab;
52 struct pcpu_freelist_node fnode;
53 };
54 };
55 };
56 union {
57 struct rcu_head rcu;
58 struct bpf_lru_node lru_node;
59 };
60 u32 hash;
61 char key[0] __aligned(8);
62};
63
64static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
65
66static bool htab_is_lru(const struct bpf_htab *htab)
67{
68 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
69 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
70}
71
72static bool htab_is_percpu(const struct bpf_htab *htab)
73{
74 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
75 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
76}
77
78static bool htab_is_prealloc(const struct bpf_htab *htab)
79{
80 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
81}
82
83static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
84 void __percpu *pptr)
85{
86 *(void __percpu **)(l->key + key_size) = pptr;
87}
88
89static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
90{
91 return *(void __percpu **)(l->key + key_size);
92}
93
94static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
95{
96 return *(void **)(l->key + roundup(map->key_size, 8));
97}
98
99static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
100{
101 return (struct htab_elem *) (htab->elems + i * htab->elem_size);
102}
103
104static void htab_free_elems(struct bpf_htab *htab)
105{
106 int i;
107
108 if (!htab_is_percpu(htab))
109 goto free_elems;
110
111 for (i = 0; i < htab->map.max_entries; i++) {
112 void __percpu *pptr;
113
114 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
115 htab->map.key_size);
116 free_percpu(pptr);
117 cond_resched();
118 }
119free_elems:
120 bpf_map_area_free(htab->elems);
121}
122
123static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
124 u32 hash)
125{
126 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
127 struct htab_elem *l;
128
129 if (node) {
130 l = container_of(node, struct htab_elem, lru_node);
131 memcpy(l->key, key, htab->map.key_size);
132 return l;
133 }
134
135 return NULL;
136}
137
138static int prealloc_init(struct bpf_htab *htab)
139{
140 u32 num_entries = htab->map.max_entries;
141 int err = -ENOMEM, i;
142
143 if (!htab_is_percpu(htab) && !htab_is_lru(htab))
144 num_entries += num_possible_cpus();
145
146 htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
147 htab->map.numa_node);
148 if (!htab->elems)
149 return -ENOMEM;
150
151 if (!htab_is_percpu(htab))
152 goto skip_percpu_elems;
153
154 for (i = 0; i < num_entries; i++) {
155 u32 size = round_up(htab->map.value_size, 8);
156 void __percpu *pptr;
157
158 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
159 if (!pptr)
160 goto free_elems;
161 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
162 pptr);
163 cond_resched();
164 }
165
166skip_percpu_elems:
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,
173 htab);
174 else
175 err = pcpu_freelist_init(&htab->freelist);
176
177 if (err)
178 goto free_elems;
179
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);
184 else
185 pcpu_freelist_populate(&htab->freelist,
186 htab->elems + offsetof(struct htab_elem, fnode),
187 htab->elem_size, num_entries);
188
189 return 0;
190
191free_elems:
192 htab_free_elems(htab);
193 return err;
194}
195
196static void prealloc_destroy(struct bpf_htab *htab)
197{
198 htab_free_elems(htab);
199
200 if (htab_is_lru(htab))
201 bpf_lru_destroy(&htab->lru);
202 else
203 pcpu_freelist_destroy(&htab->freelist);
204}
205
206static int alloc_extra_elems(struct bpf_htab *htab)
207{
208 struct htab_elem *__percpu *pptr, *l_new;
209 struct pcpu_freelist_node *l;
210 int cpu;
211
212 pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
213 GFP_USER | __GFP_NOWARN);
214 if (!pptr)
215 return -ENOMEM;
216
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
221 */
222 l_new = container_of(l, struct htab_elem, fnode);
223 *per_cpu_ptr(pptr, cpu) = l_new;
224 }
225 htab->extra_elems = pptr;
226 return 0;
227}
228
229/* Called from syscall */
230static int htab_map_alloc_check(union bpf_attr *attr)
231{
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.
240 */
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);
244
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));
249
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.
253 */
254 return -EPERM;
255
256 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)
257 /* reserved bits should not be used */
258 return -EINVAL;
259
260 if (!lru && percpu_lru)
261 return -EINVAL;
262
263 if (lru && !prealloc)
264 return -ENOTSUPP;
265
266 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
267 return -EINVAL;
268
269 /* check sanity of attributes.
270 * value_size == 0 may be allowed in the future to use map as a set
271 */
272 if (attr->max_entries == 0 || attr->key_size == 0 ||
273 attr->value_size == 0)
274 return -EINVAL;
275
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
279 */
280 return -E2BIG;
281
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()
288 */
289 return -E2BIG;
290
291 return 0;
292}
293
294static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
295{
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.
304 */
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;
308 int err, i;
309 u64 cost;
310
311 htab = kzalloc(sizeof(*htab), GFP_USER);
312 if (!htab)
313 return ERR_PTR(-ENOMEM);
314
315 bpf_map_init_from_attr(&htab->map, attr);
316
317 if (percpu_lru) {
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.
321 */
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());
327 }
328
329 /* hash table size must be power of 2 */
330 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
331
332 htab->elem_size = sizeof(struct htab_elem) +
333 round_up(htab->map.key_size, 8);
334 if (percpu)
335 htab->elem_size += sizeof(void *);
336 else
337 htab->elem_size += round_up(htab->map.value_size, 8);
338
339 err = -E2BIG;
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))
343 goto free_htab;
344
345 cost = (u64) htab->n_buckets * sizeof(struct bucket) +
346 (u64) htab->elem_size * htab->map.max_entries;
347
348 if (percpu)
349 cost += (u64) round_up(htab->map.value_size, 8) *
350 num_possible_cpus() * htab->map.max_entries;
351 else
352 cost += (u64) htab->elem_size * num_possible_cpus();
353
354 if (cost >= U32_MAX - PAGE_SIZE)
355 /* make sure page count doesn't overflow */
356 goto free_htab;
357
358 htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
359
360 /* if map size is larger than memlock limit, reject it early */
361 err = bpf_map_precharge_memlock(htab->map.pages);
362 if (err)
363 goto free_htab;
364
365 err = -ENOMEM;
366 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
367 sizeof(struct bucket),
368 htab->map.numa_node);
369 if (!htab->buckets)
370 goto free_htab;
371
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);
375 }
376
377 if (prealloc) {
378 err = prealloc_init(htab);
379 if (err)
380 goto free_buckets;
381
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.
385 */
386 err = alloc_extra_elems(htab);
387 if (err)
388 goto free_prealloc;
389 }
390 }
391
392 return &htab->map;
393
394free_prealloc:
395 prealloc_destroy(htab);
396free_buckets:
397 bpf_map_area_free(htab->buckets);
398free_htab:
399 kfree(htab);
400 return ERR_PTR(err);
401}
402
403static inline u32 htab_map_hash(const void *key, u32 key_len)
404{
405 return jhash(key, key_len, 0);
406}
407
408static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
409{
410 return &htab->buckets[hash & (htab->n_buckets - 1)];
411}
412
413static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
414{
415 return &__select_bucket(htab, hash)->head;
416}
417
418/* this lookup function can only be called with bucket lock taken */
419static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
420 void *key, u32 key_size)
421{
422 struct hlist_nulls_node *n;
423 struct htab_elem *l;
424
425 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
426 if (l->hash == hash && !memcmp(&l->key, key, key_size))
427 return l;
428
429 return NULL;
430}
431
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
435 */
436static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
437 u32 hash, void *key,
438 u32 key_size, u32 n_buckets)
439{
440 struct hlist_nulls_node *n;
441 struct htab_elem *l;
442
443again:
444 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
445 if (l->hash == hash && !memcmp(&l->key, key, key_size))
446 return l;
447
448 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
449 goto again;
450
451 return NULL;
452}
453
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().
458 */
459static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
460{
461 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
462 struct hlist_nulls_head *head;
463 struct htab_elem *l;
464 u32 hash, key_size;
465
466 /* Must be called with rcu_read_lock. */
467 WARN_ON_ONCE(!rcu_read_lock_held());
468
469 key_size = map->key_size;
470
471 hash = htab_map_hash(key, key_size);
472
473 head = select_bucket(htab, hash);
474
475 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
476
477 return l;
478}
479
480static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
481{
482 struct htab_elem *l = __htab_map_lookup_elem(map, key);
483
484 if (l)
485 return l->key + round_up(map->key_size, 8);
486
487 return NULL;
488}
489
490/* inline bpf_map_lookup_elem() call.
491 * Instead of:
492 * bpf_prog
493 * bpf_map_lookup_elem
494 * map->ops->map_lookup_elem
495 * htab_map_lookup_elem
496 * __htab_map_lookup_elem
497 * do:
498 * bpf_prog
499 * __htab_map_lookup_elem
500 */
501static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
502{
503 struct bpf_insn *insn = insn_buf;
504 const int ret = BPF_REG_0;
505
506 *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
507 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
508 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
509 offsetof(struct htab_elem, key) +
510 round_up(map->key_size, 8));
511 return insn - insn_buf;
512}
513
514static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
515{
516 struct htab_elem *l = __htab_map_lookup_elem(map, key);
517
518 if (l) {
519 bpf_lru_node_set_ref(&l->lru_node);
520 return l->key + round_up(map->key_size, 8);
521 }
522
523 return NULL;
524}
525
526static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
527 struct bpf_insn *insn_buf)
528{
529 struct bpf_insn *insn = insn_buf;
530 const int ret = BPF_REG_0;
531 const int ref_reg = BPF_REG_1;
532
533 *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
534 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
535 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
536 offsetof(struct htab_elem, lru_node) +
537 offsetof(struct bpf_lru_node, ref));
538 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
539 *insn++ = BPF_ST_MEM(BPF_B, ret,
540 offsetof(struct htab_elem, lru_node) +
541 offsetof(struct bpf_lru_node, ref),
542 1);
543 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
544 offsetof(struct htab_elem, key) +
545 round_up(map->key_size, 8));
546 return insn - insn_buf;
547}
548
549/* It is called from the bpf_lru_list when the LRU needs to delete
550 * older elements from the htab.
551 */
552static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
553{
554 struct bpf_htab *htab = (struct bpf_htab *)arg;
555 struct htab_elem *l = NULL, *tgt_l;
556 struct hlist_nulls_head *head;
557 struct hlist_nulls_node *n;
558 unsigned long flags;
559 struct bucket *b;
560
561 tgt_l = container_of(node, struct htab_elem, lru_node);
562 b = __select_bucket(htab, tgt_l->hash);
563 head = &b->head;
564
565 raw_spin_lock_irqsave(&b->lock, flags);
566
567 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
568 if (l == tgt_l) {
569 hlist_nulls_del_rcu(&l->hash_node);
570 break;
571 }
572
573 raw_spin_unlock_irqrestore(&b->lock, flags);
574
575 return l == tgt_l;
576}
577
578/* Called from syscall */
579static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
580{
581 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
582 struct hlist_nulls_head *head;
583 struct htab_elem *l, *next_l;
584 u32 hash, key_size;
585 int i = 0;
586
587 WARN_ON_ONCE(!rcu_read_lock_held());
588
589 key_size = map->key_size;
590
591 if (!key)
592 goto find_first_elem;
593
594 hash = htab_map_hash(key, key_size);
595
596 head = select_bucket(htab, hash);
597
598 /* lookup the key */
599 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
600
601 if (!l)
602 goto find_first_elem;
603
604 /* key was found, get next key in the same bucket */
605 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
606 struct htab_elem, hash_node);
607
608 if (next_l) {
609 /* if next elem in this hash list is non-zero, just return it */
610 memcpy(next_key, next_l->key, key_size);
611 return 0;
612 }
613
614 /* no more elements in this hash list, go to the next bucket */
615 i = hash & (htab->n_buckets - 1);
616 i++;
617
618find_first_elem:
619 /* iterate over buckets */
620 for (; i < htab->n_buckets; i++) {
621 head = select_bucket(htab, i);
622
623 /* pick first element in the bucket */
624 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
625 struct htab_elem, hash_node);
626 if (next_l) {
627 /* if it's not empty, just return it */
628 memcpy(next_key, next_l->key, key_size);
629 return 0;
630 }
631 }
632
633 /* iterated over all buckets and all elements */
634 return -ENOENT;
635}
636
637static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
638{
639 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
640 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
641 kfree(l);
642}
643
644static void htab_elem_free_rcu(struct rcu_head *head)
645{
646 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
647 struct bpf_htab *htab = l->htab;
648
649 /* must increment bpf_prog_active to avoid kprobe+bpf triggering while
650 * we're calling kfree, otherwise deadlock is possible if kprobes
651 * are placed somewhere inside of slub
652 */
653 preempt_disable();
654 __this_cpu_inc(bpf_prog_active);
655 htab_elem_free(htab, l);
656 __this_cpu_dec(bpf_prog_active);
657 preempt_enable();
658}
659
660static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
661{
662 struct bpf_map *map = &htab->map;
663
664 if (map->ops->map_fd_put_ptr) {
665 void *ptr = fd_htab_map_get_ptr(map, l);
666
667 map->ops->map_fd_put_ptr(ptr);
668 }
669
670 if (htab_is_prealloc(htab)) {
671 pcpu_freelist_push(&htab->freelist, &l->fnode);
672 } else {
673 atomic_dec(&htab->count);
674 l->htab = htab;
675 call_rcu(&l->rcu, htab_elem_free_rcu);
676 }
677}
678
679static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
680 void *value, bool onallcpus)
681{
682 if (!onallcpus) {
683 /* copy true value_size bytes */
684 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
685 } else {
686 u32 size = round_up(htab->map.value_size, 8);
687 int off = 0, cpu;
688
689 for_each_possible_cpu(cpu) {
690 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
691 value + off, size);
692 off += size;
693 }
694 }
695}
696
697static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
698{
699 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
700 BITS_PER_LONG == 64;
701}
702
703static u32 htab_size_value(const struct bpf_htab *htab, bool percpu)
704{
705 u32 size = htab->map.value_size;
706
707 if (percpu || fd_htab_map_needs_adjust(htab))
708 size = round_up(size, 8);
709 return size;
710}
711
712static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
713 void *value, u32 key_size, u32 hash,
714 bool percpu, bool onallcpus,
715 struct htab_elem *old_elem)
716{
717 u32 size = htab_size_value(htab, percpu);
718 bool prealloc = htab_is_prealloc(htab);
719 struct htab_elem *l_new, **pl_new;
720 void __percpu *pptr;
721
722 if (prealloc) {
723 if (old_elem) {
724 /* if we're updating the existing element,
725 * use per-cpu extra elems to avoid freelist_pop/push
726 */
727 pl_new = this_cpu_ptr(htab->extra_elems);
728 l_new = *pl_new;
729 *pl_new = old_elem;
730 } else {
731 struct pcpu_freelist_node *l;
732
733 l = pcpu_freelist_pop(&htab->freelist);
734 if (!l)
735 return ERR_PTR(-E2BIG);
736 l_new = container_of(l, struct htab_elem, fnode);
737 }
738 } else {
739 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
740 if (!old_elem) {
741 /* when map is full and update() is replacing
742 * old element, it's ok to allocate, since
743 * old element will be freed immediately.
744 * Otherwise return an error
745 */
746 atomic_dec(&htab->count);
747 return ERR_PTR(-E2BIG);
748 }
749 l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
750 htab->map.numa_node);
751 if (!l_new)
752 return ERR_PTR(-ENOMEM);
753 }
754
755 memcpy(l_new->key, key, key_size);
756 if (percpu) {
757 if (prealloc) {
758 pptr = htab_elem_get_ptr(l_new, key_size);
759 } else {
760 /* alloc_percpu zero-fills */
761 pptr = __alloc_percpu_gfp(size, 8,
762 GFP_ATOMIC | __GFP_NOWARN);
763 if (!pptr) {
764 kfree(l_new);
765 return ERR_PTR(-ENOMEM);
766 }
767 }
768
769 pcpu_copy_value(htab, pptr, value, onallcpus);
770
771 if (!prealloc)
772 htab_elem_set_ptr(l_new, key_size, pptr);
773 } else {
774 memcpy(l_new->key + round_up(key_size, 8), value, size);
775 }
776
777 l_new->hash = hash;
778 return l_new;
779}
780
781static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
782 u64 map_flags)
783{
784 if (l_old && map_flags == BPF_NOEXIST)
785 /* elem already exists */
786 return -EEXIST;
787
788 if (!l_old && map_flags == BPF_EXIST)
789 /* elem doesn't exist, cannot update it */
790 return -ENOENT;
791
792 return 0;
793}
794
795/* Called from syscall or from eBPF program */
796static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
797 u64 map_flags)
798{
799 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
800 struct htab_elem *l_new = NULL, *l_old;
801 struct hlist_nulls_head *head;
802 unsigned long flags;
803 struct bucket *b;
804 u32 key_size, hash;
805 int ret;
806
807 if (unlikely(map_flags > BPF_EXIST))
808 /* unknown flags */
809 return -EINVAL;
810
811 WARN_ON_ONCE(!rcu_read_lock_held());
812
813 key_size = map->key_size;
814
815 hash = htab_map_hash(key, key_size);
816
817 b = __select_bucket(htab, hash);
818 head = &b->head;
819
820 /* bpf_map_update_elem() can be called in_irq() */
821 raw_spin_lock_irqsave(&b->lock, flags);
822
823 l_old = lookup_elem_raw(head, hash, key, key_size);
824
825 ret = check_flags(htab, l_old, map_flags);
826 if (ret)
827 goto err;
828
829 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
830 l_old);
831 if (IS_ERR(l_new)) {
832 /* all pre-allocated elements are in use or memory exhausted */
833 ret = PTR_ERR(l_new);
834 goto err;
835 }
836
837 /* add new element to the head of the list, so that
838 * concurrent search will find it before old elem
839 */
840 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
841 if (l_old) {
842 hlist_nulls_del_rcu(&l_old->hash_node);
843 if (!htab_is_prealloc(htab))
844 free_htab_elem(htab, l_old);
845 }
846 ret = 0;
847err:
848 raw_spin_unlock_irqrestore(&b->lock, flags);
849 return ret;
850}
851
852static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
853 u64 map_flags)
854{
855 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
856 struct htab_elem *l_new, *l_old = NULL;
857 struct hlist_nulls_head *head;
858 unsigned long flags;
859 struct bucket *b;
860 u32 key_size, hash;
861 int ret;
862
863 if (unlikely(map_flags > BPF_EXIST))
864 /* unknown flags */
865 return -EINVAL;
866
867 WARN_ON_ONCE(!rcu_read_lock_held());
868
869 key_size = map->key_size;
870
871 hash = htab_map_hash(key, key_size);
872
873 b = __select_bucket(htab, hash);
874 head = &b->head;
875
876 /* For LRU, we need to alloc before taking bucket's
877 * spinlock because getting free nodes from LRU may need
878 * to remove older elements from htab and this removal
879 * operation will need a bucket lock.
880 */
881 l_new = prealloc_lru_pop(htab, key, hash);
882 if (!l_new)
883 return -ENOMEM;
884 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
885
886 /* bpf_map_update_elem() can be called in_irq() */
887 raw_spin_lock_irqsave(&b->lock, flags);
888
889 l_old = lookup_elem_raw(head, hash, key, key_size);
890
891 ret = check_flags(htab, l_old, map_flags);
892 if (ret)
893 goto err;
894
895 /* add new element to the head of the list, so that
896 * concurrent search will find it before old elem
897 */
898 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
899 if (l_old) {
900 bpf_lru_node_set_ref(&l_new->lru_node);
901 hlist_nulls_del_rcu(&l_old->hash_node);
902 }
903 ret = 0;
904
905err:
906 raw_spin_unlock_irqrestore(&b->lock, flags);
907
908 if (ret)
909 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
910 else if (l_old)
911 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
912
913 return ret;
914}
915
916static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
917 void *value, u64 map_flags,
918 bool onallcpus)
919{
920 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
921 struct htab_elem *l_new = NULL, *l_old;
922 struct hlist_nulls_head *head;
923 unsigned long flags;
924 struct bucket *b;
925 u32 key_size, hash;
926 int ret;
927
928 if (unlikely(map_flags > BPF_EXIST))
929 /* unknown flags */
930 return -EINVAL;
931
932 WARN_ON_ONCE(!rcu_read_lock_held());
933
934 key_size = map->key_size;
935
936 hash = htab_map_hash(key, key_size);
937
938 b = __select_bucket(htab, hash);
939 head = &b->head;
940
941 /* bpf_map_update_elem() can be called in_irq() */
942 raw_spin_lock_irqsave(&b->lock, flags);
943
944 l_old = lookup_elem_raw(head, hash, key, key_size);
945
946 ret = check_flags(htab, l_old, map_flags);
947 if (ret)
948 goto err;
949
950 if (l_old) {
951 /* per-cpu hash map can update value in-place */
952 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
953 value, onallcpus);
954 } else {
955 l_new = alloc_htab_elem(htab, key, value, key_size,
956 hash, true, onallcpus, NULL);
957 if (IS_ERR(l_new)) {
958 ret = PTR_ERR(l_new);
959 goto err;
960 }
961 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
962 }
963 ret = 0;
964err:
965 raw_spin_unlock_irqrestore(&b->lock, flags);
966 return ret;
967}
968
969static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
970 void *value, u64 map_flags,
971 bool onallcpus)
972{
973 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
974 struct htab_elem *l_new = NULL, *l_old;
975 struct hlist_nulls_head *head;
976 unsigned long flags;
977 struct bucket *b;
978 u32 key_size, hash;
979 int ret;
980
981 if (unlikely(map_flags > BPF_EXIST))
982 /* unknown flags */
983 return -EINVAL;
984
985 WARN_ON_ONCE(!rcu_read_lock_held());
986
987 key_size = map->key_size;
988
989 hash = htab_map_hash(key, key_size);
990
991 b = __select_bucket(htab, hash);
992 head = &b->head;
993
994 /* For LRU, we need to alloc before taking bucket's
995 * spinlock because LRU's elem alloc may need
996 * to remove older elem from htab and this removal
997 * operation will need a bucket lock.
998 */
999 if (map_flags != BPF_EXIST) {
1000 l_new = prealloc_lru_pop(htab, key, hash);
1001 if (!l_new)
1002 return -ENOMEM;
1003 }
1004
1005 /* bpf_map_update_elem() can be called in_irq() */
1006 raw_spin_lock_irqsave(&b->lock, flags);
1007
1008 l_old = lookup_elem_raw(head, hash, key, key_size);
1009
1010 ret = check_flags(htab, l_old, map_flags);
1011 if (ret)
1012 goto err;
1013
1014 if (l_old) {
1015 bpf_lru_node_set_ref(&l_old->lru_node);
1016
1017 /* per-cpu hash map can update value in-place */
1018 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1019 value, onallcpus);
1020 } else {
1021 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
1022 value, onallcpus);
1023 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1024 l_new = NULL;
1025 }
1026 ret = 0;
1027err:
1028 raw_spin_unlock_irqrestore(&b->lock, flags);
1029 if (l_new)
1030 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1031 return ret;
1032}
1033
1034static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1035 void *value, u64 map_flags)
1036{
1037 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1038}
1039
1040static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1041 void *value, u64 map_flags)
1042{
1043 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1044 false);
1045}
1046
1047/* Called from syscall or from eBPF program */
1048static int htab_map_delete_elem(struct bpf_map *map, void *key)
1049{
1050 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1051 struct hlist_nulls_head *head;
1052 struct bucket *b;
1053 struct htab_elem *l;
1054 unsigned long flags;
1055 u32 hash, key_size;
1056 int ret = -ENOENT;
1057
1058 WARN_ON_ONCE(!rcu_read_lock_held());
1059
1060 key_size = map->key_size;
1061
1062 hash = htab_map_hash(key, key_size);
1063 b = __select_bucket(htab, hash);
1064 head = &b->head;
1065
1066 raw_spin_lock_irqsave(&b->lock, flags);
1067
1068 l = lookup_elem_raw(head, hash, key, key_size);
1069
1070 if (l) {
1071 hlist_nulls_del_rcu(&l->hash_node);
1072 free_htab_elem(htab, l);
1073 ret = 0;
1074 }
1075
1076 raw_spin_unlock_irqrestore(&b->lock, flags);
1077 return ret;
1078}
1079
1080static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1081{
1082 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1083 struct hlist_nulls_head *head;
1084 struct bucket *b;
1085 struct htab_elem *l;
1086 unsigned long flags;
1087 u32 hash, key_size;
1088 int ret = -ENOENT;
1089
1090 WARN_ON_ONCE(!rcu_read_lock_held());
1091
1092 key_size = map->key_size;
1093
1094 hash = htab_map_hash(key, key_size);
1095 b = __select_bucket(htab, hash);
1096 head = &b->head;
1097
1098 raw_spin_lock_irqsave(&b->lock, flags);
1099
1100 l = lookup_elem_raw(head, hash, key, key_size);
1101
1102 if (l) {
1103 hlist_nulls_del_rcu(&l->hash_node);
1104 ret = 0;
1105 }
1106
1107 raw_spin_unlock_irqrestore(&b->lock, flags);
1108 if (l)
1109 bpf_lru_push_free(&htab->lru, &l->lru_node);
1110 return ret;
1111}
1112
1113static void delete_all_elements(struct bpf_htab *htab)
1114{
1115 int i;
1116
1117 for (i = 0; i < htab->n_buckets; i++) {
1118 struct hlist_nulls_head *head = select_bucket(htab, i);
1119 struct hlist_nulls_node *n;
1120 struct htab_elem *l;
1121
1122 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1123 hlist_nulls_del_rcu(&l->hash_node);
1124 htab_elem_free(htab, l);
1125 }
1126 }
1127}
1128
1129/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1130static void htab_map_free(struct bpf_map *map)
1131{
1132 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1133
1134 /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
1135 * so the programs (can be more than one that used this map) were
1136 * disconnected from events. Wait for outstanding critical sections in
1137 * these programs to complete
1138 */
1139 synchronize_rcu();
1140
1141 /* some of free_htab_elem() callbacks for elements of this map may
1142 * not have executed. Wait for them.
1143 */
1144 rcu_barrier();
1145 if (!htab_is_prealloc(htab))
1146 delete_all_elements(htab);
1147 else
1148 prealloc_destroy(htab);
1149
1150 free_percpu(htab->extra_elems);
1151 bpf_map_area_free(htab->buckets);
1152 kfree(htab);
1153}
1154
1155const struct bpf_map_ops htab_map_ops = {
1156 .map_alloc_check = htab_map_alloc_check,
1157 .map_alloc = htab_map_alloc,
1158 .map_free = htab_map_free,
1159 .map_get_next_key = htab_map_get_next_key,
1160 .map_lookup_elem = htab_map_lookup_elem,
1161 .map_update_elem = htab_map_update_elem,
1162 .map_delete_elem = htab_map_delete_elem,
1163 .map_gen_lookup = htab_map_gen_lookup,
1164};
1165
1166const struct bpf_map_ops htab_lru_map_ops = {
1167 .map_alloc_check = htab_map_alloc_check,
1168 .map_alloc = htab_map_alloc,
1169 .map_free = htab_map_free,
1170 .map_get_next_key = htab_map_get_next_key,
1171 .map_lookup_elem = htab_lru_map_lookup_elem,
1172 .map_update_elem = htab_lru_map_update_elem,
1173 .map_delete_elem = htab_lru_map_delete_elem,
1174 .map_gen_lookup = htab_lru_map_gen_lookup,
1175};
1176
1177/* Called from eBPF program */
1178static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1179{
1180 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1181
1182 if (l)
1183 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1184 else
1185 return NULL;
1186}
1187
1188static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1189{
1190 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1191
1192 if (l) {
1193 bpf_lru_node_set_ref(&l->lru_node);
1194 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1195 }
1196
1197 return NULL;
1198}
1199
1200int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1201{
1202 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1203 struct htab_elem *l;
1204 void __percpu *pptr;
1205 int ret = -ENOENT;
1206 int cpu, off = 0;
1207 u32 size;
1208
1209 /* per_cpu areas are zero-filled and bpf programs can only
1210 * access 'value_size' of them, so copying rounded areas
1211 * will not leak any kernel data
1212 */
1213 size = round_up(map->value_size, 8);
1214 rcu_read_lock();
1215 l = __htab_map_lookup_elem(map, key);
1216 if (!l)
1217 goto out;
1218 if (htab_is_lru(htab))
1219 bpf_lru_node_set_ref(&l->lru_node);
1220 pptr = htab_elem_get_ptr(l, map->key_size);
1221 for_each_possible_cpu(cpu) {
1222 bpf_long_memcpy(value + off,
1223 per_cpu_ptr(pptr, cpu), size);
1224 off += size;
1225 }
1226 ret = 0;
1227out:
1228 rcu_read_unlock();
1229 return ret;
1230}
1231
1232int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1233 u64 map_flags)
1234{
1235 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1236 int ret;
1237
1238 rcu_read_lock();
1239 if (htab_is_lru(htab))
1240 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1241 map_flags, true);
1242 else
1243 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1244 true);
1245 rcu_read_unlock();
1246
1247 return ret;
1248}
1249
1250const struct bpf_map_ops htab_percpu_map_ops = {
1251 .map_alloc_check = htab_map_alloc_check,
1252 .map_alloc = htab_map_alloc,
1253 .map_free = htab_map_free,
1254 .map_get_next_key = htab_map_get_next_key,
1255 .map_lookup_elem = htab_percpu_map_lookup_elem,
1256 .map_update_elem = htab_percpu_map_update_elem,
1257 .map_delete_elem = htab_map_delete_elem,
1258};
1259
1260const struct bpf_map_ops htab_lru_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_lru_percpu_map_lookup_elem,
1266 .map_update_elem = htab_lru_percpu_map_update_elem,
1267 .map_delete_elem = htab_lru_map_delete_elem,
1268};
1269
1270static int fd_htab_map_alloc_check(union bpf_attr *attr)
1271{
1272 if (attr->value_size != sizeof(u32))
1273 return -EINVAL;
1274 return htab_map_alloc_check(attr);
1275}
1276
1277static void fd_htab_map_free(struct bpf_map *map)
1278{
1279 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1280 struct hlist_nulls_node *n;
1281 struct hlist_nulls_head *head;
1282 struct htab_elem *l;
1283 int i;
1284
1285 for (i = 0; i < htab->n_buckets; i++) {
1286 head = select_bucket(htab, i);
1287
1288 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1289 void *ptr = fd_htab_map_get_ptr(map, l);
1290
1291 map->ops->map_fd_put_ptr(ptr);
1292 }
1293 }
1294
1295 htab_map_free(map);
1296}
1297
1298/* only called from syscall */
1299int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
1300{
1301 void **ptr;
1302 int ret = 0;
1303
1304 if (!map->ops->map_fd_sys_lookup_elem)
1305 return -ENOTSUPP;
1306
1307 rcu_read_lock();
1308 ptr = htab_map_lookup_elem(map, key);
1309 if (ptr)
1310 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
1311 else
1312 ret = -ENOENT;
1313 rcu_read_unlock();
1314
1315 return ret;
1316}
1317
1318/* only called from syscall */
1319int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
1320 void *key, void *value, u64 map_flags)
1321{
1322 void *ptr;
1323 int ret;
1324 u32 ufd = *(u32 *)value;
1325
1326 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
1327 if (IS_ERR(ptr))
1328 return PTR_ERR(ptr);
1329
1330 ret = htab_map_update_elem(map, key, &ptr, map_flags);
1331 if (ret)
1332 map->ops->map_fd_put_ptr(ptr);
1333
1334 return ret;
1335}
1336
1337static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
1338{
1339 struct bpf_map *map, *inner_map_meta;
1340
1341 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1342 if (IS_ERR(inner_map_meta))
1343 return inner_map_meta;
1344
1345 map = htab_map_alloc(attr);
1346 if (IS_ERR(map)) {
1347 bpf_map_meta_free(inner_map_meta);
1348 return map;
1349 }
1350
1351 map->inner_map_meta = inner_map_meta;
1352
1353 return map;
1354}
1355
1356static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
1357{
1358 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
1359
1360 if (!inner_map)
1361 return NULL;
1362
1363 return READ_ONCE(*inner_map);
1364}
1365
1366static u32 htab_of_map_gen_lookup(struct bpf_map *map,
1367 struct bpf_insn *insn_buf)
1368{
1369 struct bpf_insn *insn = insn_buf;
1370 const int ret = BPF_REG_0;
1371
1372 *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
1373 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
1374 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
1375 offsetof(struct htab_elem, key) +
1376 round_up(map->key_size, 8));
1377 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1378
1379 return insn - insn_buf;
1380}
1381
1382static void htab_of_map_free(struct bpf_map *map)
1383{
1384 bpf_map_meta_free(map->inner_map_meta);
1385 fd_htab_map_free(map);
1386}
1387
1388const struct bpf_map_ops htab_of_maps_map_ops = {
1389 .map_alloc_check = fd_htab_map_alloc_check,
1390 .map_alloc = htab_of_map_alloc,
1391 .map_free = htab_of_map_free,
1392 .map_get_next_key = htab_map_get_next_key,
1393 .map_lookup_elem = htab_of_map_lookup_elem,
1394 .map_delete_elem = htab_map_delete_elem,
1395 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1396 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1397 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1398 .map_gen_lookup = htab_of_map_gen_lookup,
1399};
1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 */
5#include <linux/bpf.h>
6#include <linux/btf.h>
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"
15
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)
19
20#define BATCH_OPS(_name) \
21 .map_lookup_batch = \
22 _name##_map_lookup_batch, \
23 .map_lookup_and_delete_batch = \
24 _name##_map_lookup_and_delete_batch, \
25 .map_update_batch = \
26 generic_map_update_batch, \
27 .map_delete_batch = \
28 generic_map_delete_batch
29
30/*
31 * The bucket lock has two protection scopes:
32 *
33 * 1) Serializing concurrent operations from BPF programs on differrent
34 * CPUs
35 *
36 * 2) Serializing concurrent operations from BPF programs and sys_bpf()
37 *
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.
49 *
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.
59 *
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*();
63 * just works.
64 *
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
70 * sections.
71 *
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.
75 *
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
78 * compiler.
79 */
80struct bucket {
81 struct hlist_nulls_head head;
82 union {
83 raw_spinlock_t raw_lock;
84 spinlock_t lock;
85 };
86};
87
88struct bpf_htab {
89 struct bpf_map map;
90 struct bucket *buckets;
91 void *elems;
92 union {
93 struct pcpu_freelist freelist;
94 struct bpf_lru lru;
95 };
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 */
100 u32 hashrnd;
101};
102
103/* each htab element is struct htab_elem + key + value */
104struct htab_elem {
105 union {
106 struct hlist_nulls_node hash_node;
107 struct {
108 void *padding;
109 union {
110 struct bpf_htab *htab;
111 struct pcpu_freelist_node fnode;
112 struct htab_elem *batch_flink;
113 };
114 };
115 };
116 union {
117 struct rcu_head rcu;
118 struct bpf_lru_node lru_node;
119 };
120 u32 hash;
121 char key[] __aligned(8);
122};
123
124static inline bool htab_is_prealloc(const struct bpf_htab *htab)
125{
126 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
127}
128
129static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
130{
131 return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
132}
133
134static void htab_init_buckets(struct bpf_htab *htab)
135{
136 unsigned i;
137
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);
142 else
143 spin_lock_init(&htab->buckets[i].lock);
144 }
145}
146
147static inline unsigned long htab_lock_bucket(const struct bpf_htab *htab,
148 struct bucket *b)
149{
150 unsigned long flags;
151
152 if (htab_use_raw_lock(htab))
153 raw_spin_lock_irqsave(&b->raw_lock, flags);
154 else
155 spin_lock_irqsave(&b->lock, flags);
156 return flags;
157}
158
159static inline void htab_unlock_bucket(const struct bpf_htab *htab,
160 struct bucket *b,
161 unsigned long flags)
162{
163 if (htab_use_raw_lock(htab))
164 raw_spin_unlock_irqrestore(&b->raw_lock, flags);
165 else
166 spin_unlock_irqrestore(&b->lock, flags);
167}
168
169static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
170
171static bool htab_is_lru(const struct bpf_htab *htab)
172{
173 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
174 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
175}
176
177static bool htab_is_percpu(const struct bpf_htab *htab)
178{
179 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
180 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
181}
182
183static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
184 void __percpu *pptr)
185{
186 *(void __percpu **)(l->key + key_size) = pptr;
187}
188
189static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
190{
191 return *(void __percpu **)(l->key + key_size);
192}
193
194static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
195{
196 return *(void **)(l->key + roundup(map->key_size, 8));
197}
198
199static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
200{
201 return (struct htab_elem *) (htab->elems + i * htab->elem_size);
202}
203
204static void htab_free_elems(struct bpf_htab *htab)
205{
206 int i;
207
208 if (!htab_is_percpu(htab))
209 goto free_elems;
210
211 for (i = 0; i < htab->map.max_entries; i++) {
212 void __percpu *pptr;
213
214 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
215 htab->map.key_size);
216 free_percpu(pptr);
217 cond_resched();
218 }
219free_elems:
220 bpf_map_area_free(htab->elems);
221}
222
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.
229 *
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.
233 */
234static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
235 u32 hash)
236{
237 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
238 struct htab_elem *l;
239
240 if (node) {
241 l = container_of(node, struct htab_elem, lru_node);
242 memcpy(l->key, key, htab->map.key_size);
243 return l;
244 }
245
246 return NULL;
247}
248
249static int prealloc_init(struct bpf_htab *htab)
250{
251 u32 num_entries = htab->map.max_entries;
252 int err = -ENOMEM, i;
253
254 if (!htab_is_percpu(htab) && !htab_is_lru(htab))
255 num_entries += num_possible_cpus();
256
257 htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
258 htab->map.numa_node);
259 if (!htab->elems)
260 return -ENOMEM;
261
262 if (!htab_is_percpu(htab))
263 goto skip_percpu_elems;
264
265 for (i = 0; i < num_entries; i++) {
266 u32 size = round_up(htab->map.value_size, 8);
267 void __percpu *pptr;
268
269 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
270 if (!pptr)
271 goto free_elems;
272 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
273 pptr);
274 cond_resched();
275 }
276
277skip_percpu_elems:
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,
284 htab);
285 else
286 err = pcpu_freelist_init(&htab->freelist);
287
288 if (err)
289 goto free_elems;
290
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);
295 else
296 pcpu_freelist_populate(&htab->freelist,
297 htab->elems + offsetof(struct htab_elem, fnode),
298 htab->elem_size, num_entries);
299
300 return 0;
301
302free_elems:
303 htab_free_elems(htab);
304 return err;
305}
306
307static void prealloc_destroy(struct bpf_htab *htab)
308{
309 htab_free_elems(htab);
310
311 if (htab_is_lru(htab))
312 bpf_lru_destroy(&htab->lru);
313 else
314 pcpu_freelist_destroy(&htab->freelist);
315}
316
317static int alloc_extra_elems(struct bpf_htab *htab)
318{
319 struct htab_elem *__percpu *pptr, *l_new;
320 struct pcpu_freelist_node *l;
321 int cpu;
322
323 pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
324 GFP_USER | __GFP_NOWARN);
325 if (!pptr)
326 return -ENOMEM;
327
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
332 */
333 l_new = container_of(l, struct htab_elem, fnode);
334 *per_cpu_ptr(pptr, cpu) = l_new;
335 }
336 htab->extra_elems = pptr;
337 return 0;
338}
339
340/* Called from syscall */
341static int htab_map_alloc_check(union bpf_attr *attr)
342{
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.
351 */
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);
356
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));
361
362 if (lru && !bpf_capable())
363 /* LRU implementation is much complicated than other
364 * maps. Hence, limit to CAP_BPF.
365 */
366 return -EPERM;
367
368 if (zero_seed && !capable(CAP_SYS_ADMIN))
369 /* Guard against local DoS, and discourage production use. */
370 return -EPERM;
371
372 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
373 !bpf_map_flags_access_ok(attr->map_flags))
374 return -EINVAL;
375
376 if (!lru && percpu_lru)
377 return -EINVAL;
378
379 if (lru && !prealloc)
380 return -ENOTSUPP;
381
382 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
383 return -EINVAL;
384
385 /* check sanity of attributes.
386 * value_size == 0 may be allowed in the future to use map as a set
387 */
388 if (attr->max_entries == 0 || attr->key_size == 0 ||
389 attr->value_size == 0)
390 return -EINVAL;
391
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
395 */
396 return -E2BIG;
397
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()
404 */
405 return -E2BIG;
406
407 return 0;
408}
409
410static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
411{
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.
420 */
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;
424 u64 cost;
425 int err;
426
427 htab = kzalloc(sizeof(*htab), GFP_USER);
428 if (!htab)
429 return ERR_PTR(-ENOMEM);
430
431 bpf_map_init_from_attr(&htab->map, attr);
432
433 if (percpu_lru) {
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.
437 */
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());
443 }
444
445 /* hash table size must be power of 2 */
446 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
447
448 htab->elem_size = sizeof(struct htab_elem) +
449 round_up(htab->map.key_size, 8);
450 if (percpu)
451 htab->elem_size += sizeof(void *);
452 else
453 htab->elem_size += round_up(htab->map.value_size, 8);
454
455 err = -E2BIG;
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))
459 goto free_htab;
460
461 cost = (u64) htab->n_buckets * sizeof(struct bucket) +
462 (u64) htab->elem_size * htab->map.max_entries;
463
464 if (percpu)
465 cost += (u64) round_up(htab->map.value_size, 8) *
466 num_possible_cpus() * htab->map.max_entries;
467 else
468 cost += (u64) htab->elem_size * num_possible_cpus();
469
470 /* if map size is larger than memlock limit, reject it */
471 err = bpf_map_charge_init(&htab->map.memory, cost);
472 if (err)
473 goto free_htab;
474
475 err = -ENOMEM;
476 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
477 sizeof(struct bucket),
478 htab->map.numa_node);
479 if (!htab->buckets)
480 goto free_charge;
481
482 if (htab->map.map_flags & BPF_F_ZERO_SEED)
483 htab->hashrnd = 0;
484 else
485 htab->hashrnd = get_random_int();
486
487 htab_init_buckets(htab);
488
489 if (prealloc) {
490 err = prealloc_init(htab);
491 if (err)
492 goto free_buckets;
493
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.
497 */
498 err = alloc_extra_elems(htab);
499 if (err)
500 goto free_prealloc;
501 }
502 }
503
504 return &htab->map;
505
506free_prealloc:
507 prealloc_destroy(htab);
508free_buckets:
509 bpf_map_area_free(htab->buckets);
510free_charge:
511 bpf_map_charge_finish(&htab->map.memory);
512free_htab:
513 kfree(htab);
514 return ERR_PTR(err);
515}
516
517static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
518{
519 return jhash(key, key_len, hashrnd);
520}
521
522static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
523{
524 return &htab->buckets[hash & (htab->n_buckets - 1)];
525}
526
527static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
528{
529 return &__select_bucket(htab, hash)->head;
530}
531
532/* this lookup function can only be called with bucket lock taken */
533static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
534 void *key, u32 key_size)
535{
536 struct hlist_nulls_node *n;
537 struct htab_elem *l;
538
539 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
540 if (l->hash == hash && !memcmp(&l->key, key, key_size))
541 return l;
542
543 return NULL;
544}
545
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
549 */
550static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
551 u32 hash, void *key,
552 u32 key_size, u32 n_buckets)
553{
554 struct hlist_nulls_node *n;
555 struct htab_elem *l;
556
557again:
558 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
559 if (l->hash == hash && !memcmp(&l->key, key, key_size))
560 return l;
561
562 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
563 goto again;
564
565 return NULL;
566}
567
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().
572 */
573static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
574{
575 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
576 struct hlist_nulls_head *head;
577 struct htab_elem *l;
578 u32 hash, key_size;
579
580 /* Must be called with rcu_read_lock. */
581 WARN_ON_ONCE(!rcu_read_lock_held());
582
583 key_size = map->key_size;
584
585 hash = htab_map_hash(key, key_size, htab->hashrnd);
586
587 head = select_bucket(htab, hash);
588
589 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
590
591 return l;
592}
593
594static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
595{
596 struct htab_elem *l = __htab_map_lookup_elem(map, key);
597
598 if (l)
599 return l->key + round_up(map->key_size, 8);
600
601 return NULL;
602}
603
604/* inline bpf_map_lookup_elem() call.
605 * Instead of:
606 * bpf_prog
607 * bpf_map_lookup_elem
608 * map->ops->map_lookup_elem
609 * htab_map_lookup_elem
610 * __htab_map_lookup_elem
611 * do:
612 * bpf_prog
613 * __htab_map_lookup_elem
614 */
615static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
616{
617 struct bpf_insn *insn = insn_buf;
618 const int ret = BPF_REG_0;
619
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;
628}
629
630static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
631 void *key, const bool mark)
632{
633 struct htab_elem *l = __htab_map_lookup_elem(map, key);
634
635 if (l) {
636 if (mark)
637 bpf_lru_node_set_ref(&l->lru_node);
638 return l->key + round_up(map->key_size, 8);
639 }
640
641 return NULL;
642}
643
644static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
645{
646 return __htab_lru_map_lookup_elem(map, key, true);
647}
648
649static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
650{
651 return __htab_lru_map_lookup_elem(map, key, false);
652}
653
654static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
655 struct bpf_insn *insn_buf)
656{
657 struct bpf_insn *insn = insn_buf;
658 const int ret = BPF_REG_0;
659 const int ref_reg = BPF_REG_1;
660
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),
672 1);
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;
677}
678
679/* It is called from the bpf_lru_list when the LRU needs to delete
680 * older elements from the htab.
681 */
682static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
683{
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;
688 unsigned long flags;
689 struct bucket *b;
690
691 tgt_l = container_of(node, struct htab_elem, lru_node);
692 b = __select_bucket(htab, tgt_l->hash);
693 head = &b->head;
694
695 flags = htab_lock_bucket(htab, b);
696
697 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
698 if (l == tgt_l) {
699 hlist_nulls_del_rcu(&l->hash_node);
700 break;
701 }
702
703 htab_unlock_bucket(htab, b, flags);
704
705 return l == tgt_l;
706}
707
708/* Called from syscall */
709static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
710{
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;
714 u32 hash, key_size;
715 int i = 0;
716
717 WARN_ON_ONCE(!rcu_read_lock_held());
718
719 key_size = map->key_size;
720
721 if (!key)
722 goto find_first_elem;
723
724 hash = htab_map_hash(key, key_size, htab->hashrnd);
725
726 head = select_bucket(htab, hash);
727
728 /* lookup the key */
729 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
730
731 if (!l)
732 goto find_first_elem;
733
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);
737
738 if (next_l) {
739 /* if next elem in this hash list is non-zero, just return it */
740 memcpy(next_key, next_l->key, key_size);
741 return 0;
742 }
743
744 /* no more elements in this hash list, go to the next bucket */
745 i = hash & (htab->n_buckets - 1);
746 i++;
747
748find_first_elem:
749 /* iterate over buckets */
750 for (; i < htab->n_buckets; i++) {
751 head = select_bucket(htab, i);
752
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);
756 if (next_l) {
757 /* if it's not empty, just return it */
758 memcpy(next_key, next_l->key, key_size);
759 return 0;
760 }
761 }
762
763 /* iterated over all buckets and all elements */
764 return -ENOENT;
765}
766
767static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
768{
769 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
770 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
771 kfree(l);
772}
773
774static void htab_elem_free_rcu(struct rcu_head *head)
775{
776 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
777 struct bpf_htab *htab = l->htab;
778
779 htab_elem_free(htab, l);
780}
781
782static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
783{
784 struct bpf_map *map = &htab->map;
785 void *ptr;
786
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);
790 }
791}
792
793static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
794{
795 htab_put_fd_value(htab, l);
796
797 if (htab_is_prealloc(htab)) {
798 __pcpu_freelist_push(&htab->freelist, &l->fnode);
799 } else {
800 atomic_dec(&htab->count);
801 l->htab = htab;
802 call_rcu(&l->rcu, htab_elem_free_rcu);
803 }
804}
805
806static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
807 void *value, bool onallcpus)
808{
809 if (!onallcpus) {
810 /* copy true value_size bytes */
811 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
812 } else {
813 u32 size = round_up(htab->map.value_size, 8);
814 int off = 0, cpu;
815
816 for_each_possible_cpu(cpu) {
817 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
818 value + off, size);
819 off += size;
820 }
821 }
822}
823
824static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
825{
826 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
827 BITS_PER_LONG == 64;
828}
829
830static 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)
834{
835 u32 size = htab->map.value_size;
836 bool prealloc = htab_is_prealloc(htab);
837 struct htab_elem *l_new, **pl_new;
838 void __percpu *pptr;
839
840 if (prealloc) {
841 if (old_elem) {
842 /* if we're updating the existing element,
843 * use per-cpu extra elems to avoid freelist_pop/push
844 */
845 pl_new = this_cpu_ptr(htab->extra_elems);
846 l_new = *pl_new;
847 htab_put_fd_value(htab, old_elem);
848 *pl_new = old_elem;
849 } else {
850 struct pcpu_freelist_node *l;
851
852 l = __pcpu_freelist_pop(&htab->freelist);
853 if (!l)
854 return ERR_PTR(-E2BIG);
855 l_new = container_of(l, struct htab_elem, fnode);
856 }
857 } else {
858 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
859 if (!old_elem) {
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
864 */
865 l_new = ERR_PTR(-E2BIG);
866 goto dec_count;
867 }
868 l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
869 htab->map.numa_node);
870 if (!l_new) {
871 l_new = ERR_PTR(-ENOMEM);
872 goto dec_count;
873 }
874 check_and_init_map_lock(&htab->map,
875 l_new->key + round_up(key_size, 8));
876 }
877
878 memcpy(l_new->key, key, key_size);
879 if (percpu) {
880 size = round_up(size, 8);
881 if (prealloc) {
882 pptr = htab_elem_get_ptr(l_new, key_size);
883 } else {
884 /* alloc_percpu zero-fills */
885 pptr = __alloc_percpu_gfp(size, 8,
886 GFP_ATOMIC | __GFP_NOWARN);
887 if (!pptr) {
888 kfree(l_new);
889 l_new = ERR_PTR(-ENOMEM);
890 goto dec_count;
891 }
892 }
893
894 pcpu_copy_value(htab, pptr, value, onallcpus);
895
896 if (!prealloc)
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);
901 } else {
902 copy_map_value(&htab->map,
903 l_new->key + round_up(key_size, 8),
904 value);
905 }
906
907 l_new->hash = hash;
908 return l_new;
909dec_count:
910 atomic_dec(&htab->count);
911 return l_new;
912}
913
914static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
915 u64 map_flags)
916{
917 if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
918 /* elem already exists */
919 return -EEXIST;
920
921 if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
922 /* elem doesn't exist, cannot update it */
923 return -ENOENT;
924
925 return 0;
926}
927
928/* Called from syscall or from eBPF program */
929static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
930 u64 map_flags)
931{
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;
935 unsigned long flags;
936 struct bucket *b;
937 u32 key_size, hash;
938 int ret;
939
940 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
941 /* unknown flags */
942 return -EINVAL;
943
944 WARN_ON_ONCE(!rcu_read_lock_held());
945
946 key_size = map->key_size;
947
948 hash = htab_map_hash(key, key_size, htab->hashrnd);
949
950 b = __select_bucket(htab, hash);
951 head = &b->head;
952
953 if (unlikely(map_flags & BPF_F_LOCK)) {
954 if (unlikely(!map_value_has_spin_lock(map)))
955 return -EINVAL;
956 /* find an element without taking the bucket lock */
957 l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
958 htab->n_buckets);
959 ret = check_flags(htab, l_old, map_flags);
960 if (ret)
961 return ret;
962 if (l_old) {
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),
966 value, false);
967 return 0;
968 }
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.
972 */
973 }
974
975 flags = htab_lock_bucket(htab, b);
976
977 l_old = lookup_elem_raw(head, hash, key, key_size);
978
979 ret = check_flags(htab, l_old, map_flags);
980 if (ret)
981 goto err;
982
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
989 */
990 copy_map_value_locked(map,
991 l_old->key + round_up(key_size, 8),
992 value, false);
993 ret = 0;
994 goto err;
995 }
996
997 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
998 l_old);
999 if (IS_ERR(l_new)) {
1000 /* all pre-allocated elements are in use or memory exhausted */
1001 ret = PTR_ERR(l_new);
1002 goto err;
1003 }
1004
1005 /* add new element to the head of the list, so that
1006 * concurrent search will find it before old elem
1007 */
1008 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1009 if (l_old) {
1010 hlist_nulls_del_rcu(&l_old->hash_node);
1011 if (!htab_is_prealloc(htab))
1012 free_htab_elem(htab, l_old);
1013 }
1014 ret = 0;
1015err:
1016 htab_unlock_bucket(htab, b, flags);
1017 return ret;
1018}
1019
1020static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1021 u64 map_flags)
1022{
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;
1027 struct bucket *b;
1028 u32 key_size, hash;
1029 int ret;
1030
1031 if (unlikely(map_flags > BPF_EXIST))
1032 /* unknown flags */
1033 return -EINVAL;
1034
1035 WARN_ON_ONCE(!rcu_read_lock_held());
1036
1037 key_size = map->key_size;
1038
1039 hash = htab_map_hash(key, key_size, htab->hashrnd);
1040
1041 b = __select_bucket(htab, hash);
1042 head = &b->head;
1043
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.
1048 */
1049 l_new = prealloc_lru_pop(htab, key, hash);
1050 if (!l_new)
1051 return -ENOMEM;
1052 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
1053
1054 flags = htab_lock_bucket(htab, b);
1055
1056 l_old = lookup_elem_raw(head, hash, key, key_size);
1057
1058 ret = check_flags(htab, l_old, map_flags);
1059 if (ret)
1060 goto err;
1061
1062 /* add new element to the head of the list, so that
1063 * concurrent search will find it before old elem
1064 */
1065 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1066 if (l_old) {
1067 bpf_lru_node_set_ref(&l_new->lru_node);
1068 hlist_nulls_del_rcu(&l_old->hash_node);
1069 }
1070 ret = 0;
1071
1072err:
1073 htab_unlock_bucket(htab, b, flags);
1074
1075 if (ret)
1076 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1077 else if (l_old)
1078 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
1079
1080 return ret;
1081}
1082
1083static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1084 void *value, u64 map_flags,
1085 bool onallcpus)
1086{
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;
1091 struct bucket *b;
1092 u32 key_size, hash;
1093 int ret;
1094
1095 if (unlikely(map_flags > BPF_EXIST))
1096 /* unknown flags */
1097 return -EINVAL;
1098
1099 WARN_ON_ONCE(!rcu_read_lock_held());
1100
1101 key_size = map->key_size;
1102
1103 hash = htab_map_hash(key, key_size, htab->hashrnd);
1104
1105 b = __select_bucket(htab, hash);
1106 head = &b->head;
1107
1108 flags = htab_lock_bucket(htab, b);
1109
1110 l_old = lookup_elem_raw(head, hash, key, key_size);
1111
1112 ret = check_flags(htab, l_old, map_flags);
1113 if (ret)
1114 goto err;
1115
1116 if (l_old) {
1117 /* per-cpu hash map can update value in-place */
1118 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1119 value, onallcpus);
1120 } else {
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);
1125 goto err;
1126 }
1127 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1128 }
1129 ret = 0;
1130err:
1131 htab_unlock_bucket(htab, b, flags);
1132 return ret;
1133}
1134
1135static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1136 void *value, u64 map_flags,
1137 bool onallcpus)
1138{
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;
1143 struct bucket *b;
1144 u32 key_size, hash;
1145 int ret;
1146
1147 if (unlikely(map_flags > BPF_EXIST))
1148 /* unknown flags */
1149 return -EINVAL;
1150
1151 WARN_ON_ONCE(!rcu_read_lock_held());
1152
1153 key_size = map->key_size;
1154
1155 hash = htab_map_hash(key, key_size, htab->hashrnd);
1156
1157 b = __select_bucket(htab, hash);
1158 head = &b->head;
1159
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.
1164 */
1165 if (map_flags != BPF_EXIST) {
1166 l_new = prealloc_lru_pop(htab, key, hash);
1167 if (!l_new)
1168 return -ENOMEM;
1169 }
1170
1171 flags = htab_lock_bucket(htab, b);
1172
1173 l_old = lookup_elem_raw(head, hash, key, key_size);
1174
1175 ret = check_flags(htab, l_old, map_flags);
1176 if (ret)
1177 goto err;
1178
1179 if (l_old) {
1180 bpf_lru_node_set_ref(&l_old->lru_node);
1181
1182 /* per-cpu hash map can update value in-place */
1183 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1184 value, onallcpus);
1185 } else {
1186 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
1187 value, onallcpus);
1188 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1189 l_new = NULL;
1190 }
1191 ret = 0;
1192err:
1193 htab_unlock_bucket(htab, b, flags);
1194 if (l_new)
1195 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1196 return ret;
1197}
1198
1199static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1200 void *value, u64 map_flags)
1201{
1202 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1203}
1204
1205static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1206 void *value, u64 map_flags)
1207{
1208 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1209 false);
1210}
1211
1212/* Called from syscall or from eBPF program */
1213static int htab_map_delete_elem(struct bpf_map *map, void *key)
1214{
1215 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1216 struct hlist_nulls_head *head;
1217 struct bucket *b;
1218 struct htab_elem *l;
1219 unsigned long flags;
1220 u32 hash, key_size;
1221 int ret = -ENOENT;
1222
1223 WARN_ON_ONCE(!rcu_read_lock_held());
1224
1225 key_size = map->key_size;
1226
1227 hash = htab_map_hash(key, key_size, htab->hashrnd);
1228 b = __select_bucket(htab, hash);
1229 head = &b->head;
1230
1231 flags = htab_lock_bucket(htab, b);
1232
1233 l = lookup_elem_raw(head, hash, key, key_size);
1234
1235 if (l) {
1236 hlist_nulls_del_rcu(&l->hash_node);
1237 free_htab_elem(htab, l);
1238 ret = 0;
1239 }
1240
1241 htab_unlock_bucket(htab, b, flags);
1242 return ret;
1243}
1244
1245static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1246{
1247 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1248 struct hlist_nulls_head *head;
1249 struct bucket *b;
1250 struct htab_elem *l;
1251 unsigned long flags;
1252 u32 hash, key_size;
1253 int ret = -ENOENT;
1254
1255 WARN_ON_ONCE(!rcu_read_lock_held());
1256
1257 key_size = map->key_size;
1258
1259 hash = htab_map_hash(key, key_size, htab->hashrnd);
1260 b = __select_bucket(htab, hash);
1261 head = &b->head;
1262
1263 flags = htab_lock_bucket(htab, b);
1264
1265 l = lookup_elem_raw(head, hash, key, key_size);
1266
1267 if (l) {
1268 hlist_nulls_del_rcu(&l->hash_node);
1269 ret = 0;
1270 }
1271
1272 htab_unlock_bucket(htab, b, flags);
1273 if (l)
1274 bpf_lru_push_free(&htab->lru, &l->lru_node);
1275 return ret;
1276}
1277
1278static void delete_all_elements(struct bpf_htab *htab)
1279{
1280 int i;
1281
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;
1286
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);
1290 }
1291 }
1292}
1293
1294/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1295static void htab_map_free(struct bpf_map *map)
1296{
1297 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1298
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.
1302 */
1303
1304 /* some of free_htab_elem() callbacks for elements of this map may
1305 * not have executed. Wait for them.
1306 */
1307 rcu_barrier();
1308 if (!htab_is_prealloc(htab))
1309 delete_all_elements(htab);
1310 else
1311 prealloc_destroy(htab);
1312
1313 free_percpu(htab->extra_elems);
1314 bpf_map_area_free(htab->buckets);
1315 kfree(htab);
1316}
1317
1318static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1319 struct seq_file *m)
1320{
1321 void *value;
1322
1323 rcu_read_lock();
1324
1325 value = htab_map_lookup_elem(map, key);
1326 if (!value) {
1327 rcu_read_unlock();
1328 return;
1329 }
1330
1331 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1332 seq_puts(m, ": ");
1333 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1334 seq_puts(m, "\n");
1335
1336 rcu_read_unlock();
1337}
1338
1339static int
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,
1344 bool is_percpu)
1345{
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;
1360 struct bucket *b;
1361 int ret = 0;
1362
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)))
1366 return -EINVAL;
1367
1368 map_flags = attr->batch.flags;
1369 if (map_flags)
1370 return -EINVAL;
1371
1372 max_count = attr->batch.count;
1373 if (!max_count)
1374 return 0;
1375
1376 if (put_user(0, &uattr->batch.count))
1377 return -EFAULT;
1378
1379 batch = 0;
1380 if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1381 return -EFAULT;
1382
1383 if (batch >= htab->n_buckets)
1384 return -ENOENT;
1385
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);
1390 if (is_percpu)
1391 value_size = size * num_possible_cpus();
1392 total = 0;
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.
1395 */
1396 bucket_size = 5;
1397
1398alloc:
1399 /* We cannot do copy_from_user or copy_to_user inside
1400 * the rcu_read_lock. Allocate enough space here.
1401 */
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) {
1405 ret = -ENOMEM;
1406 goto after_loop;
1407 }
1408
1409again:
1410 bpf_disable_instrumentation();
1411 rcu_read_lock();
1412again_nocopy:
1413 dst_key = keys;
1414 dst_val = values;
1415 b = &htab->buckets[batch];
1416 head = &b->head;
1417 /* do not grab the lock unless need it (bucket_cnt > 0). */
1418 if (locked)
1419 flags = htab_lock_bucket(htab, b);
1420
1421 bucket_cnt = 0;
1422 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1423 bucket_cnt++;
1424
1425 if (bucket_cnt && !locked) {
1426 locked = true;
1427 goto again_nocopy;
1428 }
1429
1430 if (bucket_cnt > (max_count - total)) {
1431 if (total == 0)
1432 ret = -ENOSPC;
1433 /* Note that since bucket_cnt > 0 here, it is implicit
1434 * that the locked was grabbed, so release it.
1435 */
1436 htab_unlock_bucket(htab, b, flags);
1437 rcu_read_unlock();
1438 bpf_enable_instrumentation();
1439 goto after_loop;
1440 }
1441
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.
1446 */
1447 htab_unlock_bucket(htab, b, flags);
1448 rcu_read_unlock();
1449 bpf_enable_instrumentation();
1450 kvfree(keys);
1451 kvfree(values);
1452 goto alloc;
1453 }
1454
1455 /* Next block is only safe to run if you have grabbed the lock */
1456 if (!locked)
1457 goto next_batch;
1458
1459 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1460 memcpy(dst_key, l->key, key_size);
1461
1462 if (is_percpu) {
1463 int off = 0, cpu;
1464 void __percpu *pptr;
1465
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);
1470 off += size;
1471 }
1472 } else {
1473 value = l->key + roundup_key_size;
1474 if (elem_map_flags & BPF_F_LOCK)
1475 copy_map_value_locked(map, dst_val, value,
1476 true);
1477 else
1478 copy_map_value(map, dst_val, value);
1479 check_and_init_map_lock(map, dst_val);
1480 }
1481 if (do_delete) {
1482 hlist_nulls_del_rcu(&l->hash_node);
1483
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.
1488 */
1489 if (is_lru_map) {
1490 l->batch_flink = node_to_free;
1491 node_to_free = l;
1492 } else {
1493 free_htab_elem(htab, l);
1494 }
1495 }
1496 dst_key += key_size;
1497 dst_val += value_size;
1498 }
1499
1500 htab_unlock_bucket(htab, b, flags);
1501 locked = false;
1502
1503 while (node_to_free) {
1504 l = node_to_free;
1505 node_to_free = node_to_free->batch_flink;
1506 bpf_lru_push_free(&htab->lru, &l->lru_node);
1507 }
1508
1509next_batch:
1510 /* If we are not copying data, we can go to next bucket and avoid
1511 * unlocking the rcu.
1512 */
1513 if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1514 batch++;
1515 goto again_nocopy;
1516 }
1517
1518 rcu_read_unlock();
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))) {
1524 ret = -EFAULT;
1525 goto after_loop;
1526 }
1527
1528 total += bucket_cnt;
1529 batch++;
1530 if (batch >= htab->n_buckets) {
1531 ret = -ENOENT;
1532 goto after_loop;
1533 }
1534 goto again;
1535
1536after_loop:
1537 if (ret == -EFAULT)
1538 goto out;
1539
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))
1544 ret = -EFAULT;
1545
1546out:
1547 kvfree(keys);
1548 kvfree(values);
1549 return ret;
1550}
1551
1552static int
1553htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1554 union bpf_attr __user *uattr)
1555{
1556 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1557 false, true);
1558}
1559
1560static int
1561htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1562 const union bpf_attr *attr,
1563 union bpf_attr __user *uattr)
1564{
1565 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1566 false, true);
1567}
1568
1569static int
1570htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1571 union bpf_attr __user *uattr)
1572{
1573 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1574 false, false);
1575}
1576
1577static int
1578htab_map_lookup_and_delete_batch(struct bpf_map *map,
1579 const union bpf_attr *attr,
1580 union bpf_attr __user *uattr)
1581{
1582 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1583 false, false);
1584}
1585
1586static int
1587htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1588 const union bpf_attr *attr,
1589 union bpf_attr __user *uattr)
1590{
1591 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1592 true, true);
1593}
1594
1595static int
1596htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1597 const union bpf_attr *attr,
1598 union bpf_attr __user *uattr)
1599{
1600 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1601 true, true);
1602}
1603
1604static int
1605htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1606 union bpf_attr __user *uattr)
1607{
1608 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1609 true, false);
1610}
1611
1612static int
1613htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1614 const union bpf_attr *attr,
1615 union bpf_attr __user *uattr)
1616{
1617 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1618 true, false);
1619}
1620
1621struct 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 u32 bucket_id;
1626 u32 skip_elems;
1627};
1628
1629static struct htab_elem *
1630bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1631 struct htab_elem *prev_elem)
1632{
1633 const struct bpf_htab *htab = info->htab;
1634 u32 skip_elems = info->skip_elems;
1635 u32 bucket_id = info->bucket_id;
1636 struct hlist_nulls_head *head;
1637 struct hlist_nulls_node *n;
1638 struct htab_elem *elem;
1639 struct bucket *b;
1640 u32 i, count;
1641
1642 if (bucket_id >= htab->n_buckets)
1643 return NULL;
1644
1645 /* try to find next elem in the same bucket */
1646 if (prev_elem) {
1647 /* no update/deletion on this bucket, prev_elem should be still valid
1648 * and we won't skip elements.
1649 */
1650 n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
1651 elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
1652 if (elem)
1653 return elem;
1654
1655 /* not found, unlock and go to the next bucket */
1656 b = &htab->buckets[bucket_id++];
1657 rcu_read_unlock();
1658 skip_elems = 0;
1659 }
1660
1661 for (i = bucket_id; i < htab->n_buckets; i++) {
1662 b = &htab->buckets[i];
1663 rcu_read_lock();
1664
1665 count = 0;
1666 head = &b->head;
1667 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
1668 if (count >= skip_elems) {
1669 info->bucket_id = i;
1670 info->skip_elems = count;
1671 return elem;
1672 }
1673 count++;
1674 }
1675
1676 rcu_read_unlock();
1677 skip_elems = 0;
1678 }
1679
1680 info->bucket_id = i;
1681 info->skip_elems = 0;
1682 return NULL;
1683}
1684
1685static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
1686{
1687 struct bpf_iter_seq_hash_map_info *info = seq->private;
1688 struct htab_elem *elem;
1689
1690 elem = bpf_hash_map_seq_find_next(info, NULL);
1691 if (!elem)
1692 return NULL;
1693
1694 if (*pos == 0)
1695 ++*pos;
1696 return elem;
1697}
1698
1699static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1700{
1701 struct bpf_iter_seq_hash_map_info *info = seq->private;
1702
1703 ++*pos;
1704 ++info->skip_elems;
1705 return bpf_hash_map_seq_find_next(info, v);
1706}
1707
1708static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
1709{
1710 struct bpf_iter_seq_hash_map_info *info = seq->private;
1711 u32 roundup_key_size, roundup_value_size;
1712 struct bpf_iter__bpf_map_elem ctx = {};
1713 struct bpf_map *map = info->map;
1714 struct bpf_iter_meta meta;
1715 int ret = 0, off = 0, cpu;
1716 struct bpf_prog *prog;
1717 void __percpu *pptr;
1718
1719 meta.seq = seq;
1720 prog = bpf_iter_get_info(&meta, elem == NULL);
1721 if (prog) {
1722 ctx.meta = &meta;
1723 ctx.map = info->map;
1724 if (elem) {
1725 roundup_key_size = round_up(map->key_size, 8);
1726 ctx.key = elem->key;
1727 if (!info->percpu_value_buf) {
1728 ctx.value = elem->key + roundup_key_size;
1729 } else {
1730 roundup_value_size = round_up(map->value_size, 8);
1731 pptr = htab_elem_get_ptr(elem, map->key_size);
1732 for_each_possible_cpu(cpu) {
1733 bpf_long_memcpy(info->percpu_value_buf + off,
1734 per_cpu_ptr(pptr, cpu),
1735 roundup_value_size);
1736 off += roundup_value_size;
1737 }
1738 ctx.value = info->percpu_value_buf;
1739 }
1740 }
1741 ret = bpf_iter_run_prog(prog, &ctx);
1742 }
1743
1744 return ret;
1745}
1746
1747static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
1748{
1749 return __bpf_hash_map_seq_show(seq, v);
1750}
1751
1752static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
1753{
1754 if (!v)
1755 (void)__bpf_hash_map_seq_show(seq, NULL);
1756 else
1757 rcu_read_unlock();
1758}
1759
1760static int bpf_iter_init_hash_map(void *priv_data,
1761 struct bpf_iter_aux_info *aux)
1762{
1763 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1764 struct bpf_map *map = aux->map;
1765 void *value_buf;
1766 u32 buf_size;
1767
1768 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
1769 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
1770 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
1771 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
1772 if (!value_buf)
1773 return -ENOMEM;
1774
1775 seq_info->percpu_value_buf = value_buf;
1776 }
1777
1778 seq_info->map = map;
1779 seq_info->htab = container_of(map, struct bpf_htab, map);
1780 return 0;
1781}
1782
1783static void bpf_iter_fini_hash_map(void *priv_data)
1784{
1785 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1786
1787 kfree(seq_info->percpu_value_buf);
1788}
1789
1790static const struct seq_operations bpf_hash_map_seq_ops = {
1791 .start = bpf_hash_map_seq_start,
1792 .next = bpf_hash_map_seq_next,
1793 .stop = bpf_hash_map_seq_stop,
1794 .show = bpf_hash_map_seq_show,
1795};
1796
1797static const struct bpf_iter_seq_info iter_seq_info = {
1798 .seq_ops = &bpf_hash_map_seq_ops,
1799 .init_seq_private = bpf_iter_init_hash_map,
1800 .fini_seq_private = bpf_iter_fini_hash_map,
1801 .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
1802};
1803
1804static int htab_map_btf_id;
1805const struct bpf_map_ops htab_map_ops = {
1806 .map_alloc_check = htab_map_alloc_check,
1807 .map_alloc = htab_map_alloc,
1808 .map_free = htab_map_free,
1809 .map_get_next_key = htab_map_get_next_key,
1810 .map_lookup_elem = htab_map_lookup_elem,
1811 .map_update_elem = htab_map_update_elem,
1812 .map_delete_elem = htab_map_delete_elem,
1813 .map_gen_lookup = htab_map_gen_lookup,
1814 .map_seq_show_elem = htab_map_seq_show_elem,
1815 BATCH_OPS(htab),
1816 .map_btf_name = "bpf_htab",
1817 .map_btf_id = &htab_map_btf_id,
1818 .iter_seq_info = &iter_seq_info,
1819};
1820
1821static int htab_lru_map_btf_id;
1822const struct bpf_map_ops htab_lru_map_ops = {
1823 .map_alloc_check = htab_map_alloc_check,
1824 .map_alloc = htab_map_alloc,
1825 .map_free = htab_map_free,
1826 .map_get_next_key = htab_map_get_next_key,
1827 .map_lookup_elem = htab_lru_map_lookup_elem,
1828 .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
1829 .map_update_elem = htab_lru_map_update_elem,
1830 .map_delete_elem = htab_lru_map_delete_elem,
1831 .map_gen_lookup = htab_lru_map_gen_lookup,
1832 .map_seq_show_elem = htab_map_seq_show_elem,
1833 BATCH_OPS(htab_lru),
1834 .map_btf_name = "bpf_htab",
1835 .map_btf_id = &htab_lru_map_btf_id,
1836 .iter_seq_info = &iter_seq_info,
1837};
1838
1839/* Called from eBPF program */
1840static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1841{
1842 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1843
1844 if (l)
1845 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1846 else
1847 return NULL;
1848}
1849
1850static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1851{
1852 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1853
1854 if (l) {
1855 bpf_lru_node_set_ref(&l->lru_node);
1856 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1857 }
1858
1859 return NULL;
1860}
1861
1862int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1863{
1864 struct htab_elem *l;
1865 void __percpu *pptr;
1866 int ret = -ENOENT;
1867 int cpu, off = 0;
1868 u32 size;
1869
1870 /* per_cpu areas are zero-filled and bpf programs can only
1871 * access 'value_size' of them, so copying rounded areas
1872 * will not leak any kernel data
1873 */
1874 size = round_up(map->value_size, 8);
1875 rcu_read_lock();
1876 l = __htab_map_lookup_elem(map, key);
1877 if (!l)
1878 goto out;
1879 /* We do not mark LRU map element here in order to not mess up
1880 * eviction heuristics when user space does a map walk.
1881 */
1882 pptr = htab_elem_get_ptr(l, map->key_size);
1883 for_each_possible_cpu(cpu) {
1884 bpf_long_memcpy(value + off,
1885 per_cpu_ptr(pptr, cpu), size);
1886 off += size;
1887 }
1888 ret = 0;
1889out:
1890 rcu_read_unlock();
1891 return ret;
1892}
1893
1894int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1895 u64 map_flags)
1896{
1897 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1898 int ret;
1899
1900 rcu_read_lock();
1901 if (htab_is_lru(htab))
1902 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1903 map_flags, true);
1904 else
1905 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1906 true);
1907 rcu_read_unlock();
1908
1909 return ret;
1910}
1911
1912static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
1913 struct seq_file *m)
1914{
1915 struct htab_elem *l;
1916 void __percpu *pptr;
1917 int cpu;
1918
1919 rcu_read_lock();
1920
1921 l = __htab_map_lookup_elem(map, key);
1922 if (!l) {
1923 rcu_read_unlock();
1924 return;
1925 }
1926
1927 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1928 seq_puts(m, ": {\n");
1929 pptr = htab_elem_get_ptr(l, map->key_size);
1930 for_each_possible_cpu(cpu) {
1931 seq_printf(m, "\tcpu%d: ", cpu);
1932 btf_type_seq_show(map->btf, map->btf_value_type_id,
1933 per_cpu_ptr(pptr, cpu), m);
1934 seq_puts(m, "\n");
1935 }
1936 seq_puts(m, "}\n");
1937
1938 rcu_read_unlock();
1939}
1940
1941static int htab_percpu_map_btf_id;
1942const struct bpf_map_ops htab_percpu_map_ops = {
1943 .map_alloc_check = htab_map_alloc_check,
1944 .map_alloc = htab_map_alloc,
1945 .map_free = htab_map_free,
1946 .map_get_next_key = htab_map_get_next_key,
1947 .map_lookup_elem = htab_percpu_map_lookup_elem,
1948 .map_update_elem = htab_percpu_map_update_elem,
1949 .map_delete_elem = htab_map_delete_elem,
1950 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
1951 BATCH_OPS(htab_percpu),
1952 .map_btf_name = "bpf_htab",
1953 .map_btf_id = &htab_percpu_map_btf_id,
1954 .iter_seq_info = &iter_seq_info,
1955};
1956
1957static int htab_lru_percpu_map_btf_id;
1958const struct bpf_map_ops htab_lru_percpu_map_ops = {
1959 .map_alloc_check = htab_map_alloc_check,
1960 .map_alloc = htab_map_alloc,
1961 .map_free = htab_map_free,
1962 .map_get_next_key = htab_map_get_next_key,
1963 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
1964 .map_update_elem = htab_lru_percpu_map_update_elem,
1965 .map_delete_elem = htab_lru_map_delete_elem,
1966 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
1967 BATCH_OPS(htab_lru_percpu),
1968 .map_btf_name = "bpf_htab",
1969 .map_btf_id = &htab_lru_percpu_map_btf_id,
1970 .iter_seq_info = &iter_seq_info,
1971};
1972
1973static int fd_htab_map_alloc_check(union bpf_attr *attr)
1974{
1975 if (attr->value_size != sizeof(u32))
1976 return -EINVAL;
1977 return htab_map_alloc_check(attr);
1978}
1979
1980static void fd_htab_map_free(struct bpf_map *map)
1981{
1982 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1983 struct hlist_nulls_node *n;
1984 struct hlist_nulls_head *head;
1985 struct htab_elem *l;
1986 int i;
1987
1988 for (i = 0; i < htab->n_buckets; i++) {
1989 head = select_bucket(htab, i);
1990
1991 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1992 void *ptr = fd_htab_map_get_ptr(map, l);
1993
1994 map->ops->map_fd_put_ptr(ptr);
1995 }
1996 }
1997
1998 htab_map_free(map);
1999}
2000
2001/* only called from syscall */
2002int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2003{
2004 void **ptr;
2005 int ret = 0;
2006
2007 if (!map->ops->map_fd_sys_lookup_elem)
2008 return -ENOTSUPP;
2009
2010 rcu_read_lock();
2011 ptr = htab_map_lookup_elem(map, key);
2012 if (ptr)
2013 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2014 else
2015 ret = -ENOENT;
2016 rcu_read_unlock();
2017
2018 return ret;
2019}
2020
2021/* only called from syscall */
2022int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2023 void *key, void *value, u64 map_flags)
2024{
2025 void *ptr;
2026 int ret;
2027 u32 ufd = *(u32 *)value;
2028
2029 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2030 if (IS_ERR(ptr))
2031 return PTR_ERR(ptr);
2032
2033 ret = htab_map_update_elem(map, key, &ptr, map_flags);
2034 if (ret)
2035 map->ops->map_fd_put_ptr(ptr);
2036
2037 return ret;
2038}
2039
2040static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2041{
2042 struct bpf_map *map, *inner_map_meta;
2043
2044 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2045 if (IS_ERR(inner_map_meta))
2046 return inner_map_meta;
2047
2048 map = htab_map_alloc(attr);
2049 if (IS_ERR(map)) {
2050 bpf_map_meta_free(inner_map_meta);
2051 return map;
2052 }
2053
2054 map->inner_map_meta = inner_map_meta;
2055
2056 return map;
2057}
2058
2059static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2060{
2061 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
2062
2063 if (!inner_map)
2064 return NULL;
2065
2066 return READ_ONCE(*inner_map);
2067}
2068
2069static u32 htab_of_map_gen_lookup(struct bpf_map *map,
2070 struct bpf_insn *insn_buf)
2071{
2072 struct bpf_insn *insn = insn_buf;
2073 const int ret = BPF_REG_0;
2074
2075 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2076 (void *(*)(struct bpf_map *map, void *key))NULL));
2077 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
2078 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2079 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2080 offsetof(struct htab_elem, key) +
2081 round_up(map->key_size, 8));
2082 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2083
2084 return insn - insn_buf;
2085}
2086
2087static void htab_of_map_free(struct bpf_map *map)
2088{
2089 bpf_map_meta_free(map->inner_map_meta);
2090 fd_htab_map_free(map);
2091}
2092
2093static int htab_of_maps_map_btf_id;
2094const struct bpf_map_ops htab_of_maps_map_ops = {
2095 .map_alloc_check = fd_htab_map_alloc_check,
2096 .map_alloc = htab_of_map_alloc,
2097 .map_free = htab_of_map_free,
2098 .map_get_next_key = htab_map_get_next_key,
2099 .map_lookup_elem = htab_of_map_lookup_elem,
2100 .map_delete_elem = htab_map_delete_elem,
2101 .map_fd_get_ptr = bpf_map_fd_get_ptr,
2102 .map_fd_put_ptr = bpf_map_fd_put_ptr,
2103 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2104 .map_gen_lookup = htab_of_map_gen_lookup,
2105 .map_check_btf = map_check_no_btf,
2106 .map_btf_name = "bpf_htab",
2107 .map_btf_id = &htab_of_maps_map_btf_id,
2108};