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Merge tag 'regmap-fix-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux/fpc-iii.git] / kernel / bpf / hashtab.c
blobc1ac7f964bc997925fd427f5192168829d812e5d
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 <linux/rcupdate_trace.h>
13 #include "percpu_freelist.h"
14 #include "bpf_lru_list.h"
15 #include "map_in_map.h"
16
17 #define HTAB_CREATE_FLAG_MASK \
18 (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
19 BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
20
21 #define BATCH_OPS(_name) \
22 .map_lookup_batch = \
23 _name##_map_lookup_batch, \
24 .map_lookup_and_delete_batch = \
25 _name##_map_lookup_and_delete_batch, \
26 .map_update_batch = \
27 generic_map_update_batch, \
28 .map_delete_batch = \
29 generic_map_delete_batch
30
31 /*
32 * The bucket lock has two protection scopes:
33 *
34 * 1) Serializing concurrent operations from BPF programs on differrent
35 * CPUs
36 *
37 * 2) Serializing concurrent operations from BPF programs and sys_bpf()
38 *
39 * BPF programs can execute in any context including perf, kprobes and
40 * tracing. As there are almost no limits where perf, kprobes and tracing
41 * can be invoked from the lock operations need to be protected against
42 * deadlocks. Deadlocks can be caused by recursion and by an invocation in
43 * the lock held section when functions which acquire this lock are invoked
44 * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
45 * variable bpf_prog_active, which prevents BPF programs attached to perf
46 * events, kprobes and tracing to be invoked before the prior invocation
47 * from one of these contexts completed. sys_bpf() uses the same mechanism
48 * by pinning the task to the current CPU and incrementing the recursion
49 * protection accross the map operation.
50 *
51 * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
52 * operations like memory allocations (even with GFP_ATOMIC) from atomic
53 * contexts. This is required because even with GFP_ATOMIC the memory
54 * allocator calls into code pathes which acquire locks with long held lock
55 * sections. To ensure the deterministic behaviour these locks are regular
56 * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
57 * true atomic contexts on an RT kernel are the low level hardware
58 * handling, scheduling, low level interrupt handling, NMIs etc. None of
59 * these contexts should ever do memory allocations.
60 *
61 * As regular device interrupt handlers and soft interrupts are forced into
62 * thread context, the existing code which does
63 * spin_lock*(); alloc(GPF_ATOMIC); spin_unlock*();
64 * just works.
65 *
66 * In theory the BPF locks could be converted to regular spinlocks as well,
67 * but the bucket locks and percpu_freelist locks can be taken from
68 * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
69 * atomic contexts even on RT. These mechanisms require preallocated maps,
70 * so there is no need to invoke memory allocations within the lock held
71 * sections.
72 *
73 * BPF maps which need dynamic allocation are only used from (forced)
74 * thread context on RT and can therefore use regular spinlocks which in
75 * turn allows to invoke memory allocations from the lock held section.
76 *
77 * On a non RT kernel this distinction is neither possible nor required.
78 * spinlock maps to raw_spinlock and the extra code is optimized out by the
79 * compiler.
80 */
81 struct bucket {
82 struct hlist_nulls_head head;
83 union {
84 raw_spinlock_t raw_lock;
85 spinlock_t lock;
86 };
87 };
88
89 #define HASHTAB_MAP_LOCK_COUNT 8
90 #define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
91
92 struct bpf_htab {
93 struct bpf_map map;
94 struct bucket *buckets;
95 void *elems;
96 union {
97 struct pcpu_freelist freelist;
98 struct bpf_lru lru;
99 };
100 struct htab_elem *__percpu *extra_elems;
101 atomic_t count; /* number of elements in this hashtable */
102 u32 n_buckets; /* number of hash buckets */
103 u32 elem_size; /* size of each element in bytes */
104 u32 hashrnd;
105 struct lock_class_key lockdep_key;
106 int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
107 };
108
109 /* each htab element is struct htab_elem + key + value */
110 struct htab_elem {
111 union {
112 struct hlist_nulls_node hash_node;
113 struct {
114 void *padding;
115 union {
116 struct bpf_htab *htab;
117 struct pcpu_freelist_node fnode;
118 struct htab_elem *batch_flink;
119 };
120 };
121 };
122 union {
123 struct rcu_head rcu;
124 struct bpf_lru_node lru_node;
125 };
126 u32 hash;
127 char key[] __aligned(8);
128 };
129
130 static inline bool htab_is_prealloc(const struct bpf_htab *htab)
131 {
132 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
133 }
134
135 static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
136 {
137 return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
138 }
139
140 static void htab_init_buckets(struct bpf_htab *htab)
141 {
142 unsigned i;
143
144 for (i = 0; i < htab->n_buckets; i++) {
145 INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
146 if (htab_use_raw_lock(htab)) {
147 raw_spin_lock_init(&htab->buckets[i].raw_lock);
148 lockdep_set_class(&htab->buckets[i].raw_lock,
149 &htab->lockdep_key);
150 } else {
151 spin_lock_init(&htab->buckets[i].lock);
152 lockdep_set_class(&htab->buckets[i].lock,
153 &htab->lockdep_key);
154 }
155 cond_resched();
156 }
157 }
158
159 static inline int htab_lock_bucket(const struct bpf_htab *htab,
160 struct bucket *b, u32 hash,
161 unsigned long *pflags)
162 {
163 unsigned long flags;
164
165 hash = hash & HASHTAB_MAP_LOCK_MASK;
166
167 migrate_disable();
168 if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
169 __this_cpu_dec(*(htab->map_locked[hash]));
170 migrate_enable();
171 return -EBUSY;
172 }
173
174 if (htab_use_raw_lock(htab))
175 raw_spin_lock_irqsave(&b->raw_lock, flags);
176 else
177 spin_lock_irqsave(&b->lock, flags);
178 *pflags = flags;
179
180 return 0;
181 }
182
183 static inline void htab_unlock_bucket(const struct bpf_htab *htab,
184 struct bucket *b, u32 hash,
185 unsigned long flags)
186 {
187 hash = hash & HASHTAB_MAP_LOCK_MASK;
188 if (htab_use_raw_lock(htab))
189 raw_spin_unlock_irqrestore(&b->raw_lock, flags);
190 else
191 spin_unlock_irqrestore(&b->lock, flags);
192 __this_cpu_dec(*(htab->map_locked[hash]));
193 migrate_enable();
194 }
195
196 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
197
198 static bool htab_is_lru(const struct bpf_htab *htab)
199 {
200 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
201 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
202 }
203
204 static bool htab_is_percpu(const struct bpf_htab *htab)
205 {
206 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
207 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
208 }
209
210 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
211 void __percpu *pptr)
212 {
213 *(void __percpu **)(l->key + key_size) = pptr;
214 }
215
216 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
217 {
218 return *(void __percpu **)(l->key + key_size);
219 }
220
221 static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
222 {
223 return *(void **)(l->key + roundup(map->key_size, 8));
224 }
225
226 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
227 {
228 return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
229 }
230
231 static void htab_free_elems(struct bpf_htab *htab)
232 {
233 int i;
234
235 if (!htab_is_percpu(htab))
236 goto free_elems;
237
238 for (i = 0; i < htab->map.max_entries; i++) {
239 void __percpu *pptr;
240
241 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
242 htab->map.key_size);
243 free_percpu(pptr);
244 cond_resched();
245 }
246 free_elems:
247 bpf_map_area_free(htab->elems);
248 }
249
250 /* The LRU list has a lock (lru_lock). Each htab bucket has a lock
251 * (bucket_lock). If both locks need to be acquired together, the lock
252 * order is always lru_lock -> bucket_lock and this only happens in
253 * bpf_lru_list.c logic. For example, certain code path of
254 * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
255 * will acquire lru_lock first followed by acquiring bucket_lock.
256 *
257 * In hashtab.c, to avoid deadlock, lock acquisition of
258 * bucket_lock followed by lru_lock is not allowed. In such cases,
259 * bucket_lock needs to be released first before acquiring lru_lock.
260 */
261 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
262 u32 hash)
263 {
264 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
265 struct htab_elem *l;
266
267 if (node) {
268 l = container_of(node, struct htab_elem, lru_node);
269 memcpy(l->key, key, htab->map.key_size);
270 return l;
271 }
272
273 return NULL;
274 }
275
276 static int prealloc_init(struct bpf_htab *htab)
277 {
278 u32 num_entries = htab->map.max_entries;
279 int err = -ENOMEM, i;
280
281 if (!htab_is_percpu(htab) && !htab_is_lru(htab))
282 num_entries += num_possible_cpus();
283
284 htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
285 htab->map.numa_node);
286 if (!htab->elems)
287 return -ENOMEM;
288
289 if (!htab_is_percpu(htab))
290 goto skip_percpu_elems;
291
292 for (i = 0; i < num_entries; i++) {
293 u32 size = round_up(htab->map.value_size, 8);
294 void __percpu *pptr;
295
296 pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
297 GFP_USER | __GFP_NOWARN);
298 if (!pptr)
299 goto free_elems;
300 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
301 pptr);
302 cond_resched();
303 }
304
305 skip_percpu_elems:
306 if (htab_is_lru(htab))
307 err = bpf_lru_init(&htab->lru,
308 htab->map.map_flags & BPF_F_NO_COMMON_LRU,
309 offsetof(struct htab_elem, hash) -
310 offsetof(struct htab_elem, lru_node),
311 htab_lru_map_delete_node,
312 htab);
313 else
314 err = pcpu_freelist_init(&htab->freelist);
315
316 if (err)
317 goto free_elems;
318
319 if (htab_is_lru(htab))
320 bpf_lru_populate(&htab->lru, htab->elems,
321 offsetof(struct htab_elem, lru_node),
322 htab->elem_size, num_entries);
323 else
324 pcpu_freelist_populate(&htab->freelist,
325 htab->elems + offsetof(struct htab_elem, fnode),
326 htab->elem_size, num_entries);
327
328 return 0;
329
330 free_elems:
331 htab_free_elems(htab);
332 return err;
333 }
334
335 static void prealloc_destroy(struct bpf_htab *htab)
336 {
337 htab_free_elems(htab);
338
339 if (htab_is_lru(htab))
340 bpf_lru_destroy(&htab->lru);
341 else
342 pcpu_freelist_destroy(&htab->freelist);
343 }
344
345 static int alloc_extra_elems(struct bpf_htab *htab)
346 {
347 struct htab_elem *__percpu *pptr, *l_new;
348 struct pcpu_freelist_node *l;
349 int cpu;
350
351 pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
352 GFP_USER | __GFP_NOWARN);
353 if (!pptr)
354 return -ENOMEM;
355
356 for_each_possible_cpu(cpu) {
357 l = pcpu_freelist_pop(&htab->freelist);
358 /* pop will succeed, since prealloc_init()
359 * preallocated extra num_possible_cpus elements
360 */
361 l_new = container_of(l, struct htab_elem, fnode);
362 *per_cpu_ptr(pptr, cpu) = l_new;
363 }
364 htab->extra_elems = pptr;
365 return 0;
366 }
367
368 /* Called from syscall */
369 static int htab_map_alloc_check(union bpf_attr *attr)
370 {
371 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
372 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
373 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
374 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
375 /* percpu_lru means each cpu has its own LRU list.
376 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
377 * the map's value itself is percpu. percpu_lru has
378 * nothing to do with the map's value.
379 */
380 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
381 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
382 bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
383 int numa_node = bpf_map_attr_numa_node(attr);
384
385 BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
386 offsetof(struct htab_elem, hash_node.pprev));
387 BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
388 offsetof(struct htab_elem, hash_node.pprev));
389
390 if (lru && !bpf_capable())
391 /* LRU implementation is much complicated than other
392 * maps. Hence, limit to CAP_BPF.
393 */
394 return -EPERM;
395
396 if (zero_seed && !capable(CAP_SYS_ADMIN))
397 /* Guard against local DoS, and discourage production use. */
398 return -EPERM;
399
400 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
401 !bpf_map_flags_access_ok(attr->map_flags))
402 return -EINVAL;
403
404 if (!lru && percpu_lru)
405 return -EINVAL;
406
407 if (lru && !prealloc)
408 return -ENOTSUPP;
409
410 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
411 return -EINVAL;
412
413 /* check sanity of attributes.
414 * value_size == 0 may be allowed in the future to use map as a set
415 */
416 if (attr->max_entries == 0 || attr->key_size == 0 ||
417 attr->value_size == 0)
418 return -EINVAL;
419
420 if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
421 sizeof(struct htab_elem))
422 /* if key_size + value_size is bigger, the user space won't be
423 * able to access the elements via bpf syscall. This check
424 * also makes sure that the elem_size doesn't overflow and it's
425 * kmalloc-able later in htab_map_update_elem()
426 */
427 return -E2BIG;
428
429 return 0;
430 }
431
432 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
433 {
434 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
435 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
436 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
437 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
438 /* percpu_lru means each cpu has its own LRU list.
439 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
440 * the map's value itself is percpu. percpu_lru has
441 * nothing to do with the map's value.
442 */
443 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
444 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
445 struct bpf_htab *htab;
446 int err, i;
447
448 htab = kzalloc(sizeof(*htab), GFP_USER | __GFP_ACCOUNT);
449 if (!htab)
450 return ERR_PTR(-ENOMEM);
451
452 lockdep_register_key(&htab->lockdep_key);
453
454 bpf_map_init_from_attr(&htab->map, attr);
455
456 if (percpu_lru) {
457 /* ensure each CPU's lru list has >=1 elements.
458 * since we are at it, make each lru list has the same
459 * number of elements.
460 */
461 htab->map.max_entries = roundup(attr->max_entries,
462 num_possible_cpus());
463 if (htab->map.max_entries < attr->max_entries)
464 htab->map.max_entries = rounddown(attr->max_entries,
465 num_possible_cpus());
466 }
467
468 /* hash table size must be power of 2 */
469 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
470
471 htab->elem_size = sizeof(struct htab_elem) +
472 round_up(htab->map.key_size, 8);
473 if (percpu)
474 htab->elem_size += sizeof(void *);
475 else
476 htab->elem_size += round_up(htab->map.value_size, 8);
477
478 err = -E2BIG;
479 /* prevent zero size kmalloc and check for u32 overflow */
480 if (htab->n_buckets == 0 ||
481 htab->n_buckets > U32_MAX / sizeof(struct bucket))
482 goto free_htab;
483
484 err = -ENOMEM;
485 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
486 sizeof(struct bucket),
487 htab->map.numa_node);
488 if (!htab->buckets)
489 goto free_htab;
490
491 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
492 htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
493 sizeof(int),
494 sizeof(int),
495 GFP_USER);
496 if (!htab->map_locked[i])
497 goto free_map_locked;
498 }
499
500 if (htab->map.map_flags & BPF_F_ZERO_SEED)
501 htab->hashrnd = 0;
502 else
503 htab->hashrnd = get_random_int();
504
505 htab_init_buckets(htab);
506
507 if (prealloc) {
508 err = prealloc_init(htab);
509 if (err)
510 goto free_map_locked;
511
512 if (!percpu && !lru) {
513 /* lru itself can remove the least used element, so
514 * there is no need for an extra elem during map_update.
515 */
516 err = alloc_extra_elems(htab);
517 if (err)
518 goto free_prealloc;
519 }
520 }
521
522 return &htab->map;
523
524 free_prealloc:
525 prealloc_destroy(htab);
526 free_map_locked:
527 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
528 free_percpu(htab->map_locked[i]);
529 bpf_map_area_free(htab->buckets);
530 free_htab:
531 lockdep_unregister_key(&htab->lockdep_key);
532 kfree(htab);
533 return ERR_PTR(err);
534 }
535
536 static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
537 {
538 return jhash(key, key_len, hashrnd);
539 }
540
541 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
542 {
543 return &htab->buckets[hash & (htab->n_buckets - 1)];
544 }
545
546 static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
547 {
548 return &__select_bucket(htab, hash)->head;
549 }
550
551 /* this lookup function can only be called with bucket lock taken */
552 static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
553 void *key, u32 key_size)
554 {
555 struct hlist_nulls_node *n;
556 struct htab_elem *l;
557
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 return NULL;
563 }
564
565 /* can be called without bucket lock. it will repeat the loop in
566 * the unlikely event when elements moved from one bucket into another
567 * while link list is being walked
568 */
569 static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
570 u32 hash, void *key,
571 u32 key_size, u32 n_buckets)
572 {
573 struct hlist_nulls_node *n;
574 struct htab_elem *l;
575
576 again:
577 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
578 if (l->hash == hash && !memcmp(&l->key, key, key_size))
579 return l;
580
581 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
582 goto again;
583
584 return NULL;
585 }
586
587 /* Called from syscall or from eBPF program directly, so
588 * arguments have to match bpf_map_lookup_elem() exactly.
589 * The return value is adjusted by BPF instructions
590 * in htab_map_gen_lookup().
591 */
592 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
593 {
594 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
595 struct hlist_nulls_head *head;
596 struct htab_elem *l;
597 u32 hash, key_size;
598
599 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
600
601 key_size = map->key_size;
602
603 hash = htab_map_hash(key, key_size, htab->hashrnd);
604
605 head = select_bucket(htab, hash);
606
607 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
608
609 return l;
610 }
611
612 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
613 {
614 struct htab_elem *l = __htab_map_lookup_elem(map, key);
615
616 if (l)
617 return l->key + round_up(map->key_size, 8);
618
619 return NULL;
620 }
621
622 /* inline bpf_map_lookup_elem() call.
623 * Instead of:
624 * bpf_prog
625 * bpf_map_lookup_elem
626 * map->ops->map_lookup_elem
627 * htab_map_lookup_elem
628 * __htab_map_lookup_elem
629 * do:
630 * bpf_prog
631 * __htab_map_lookup_elem
632 */
633 static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
634 {
635 struct bpf_insn *insn = insn_buf;
636 const int ret = BPF_REG_0;
637
638 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
639 (void *(*)(struct bpf_map *map, void *key))NULL));
640 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
641 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
642 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
643 offsetof(struct htab_elem, key) +
644 round_up(map->key_size, 8));
645 return insn - insn_buf;
646 }
647
648 static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
649 void *key, const bool mark)
650 {
651 struct htab_elem *l = __htab_map_lookup_elem(map, key);
652
653 if (l) {
654 if (mark)
655 bpf_lru_node_set_ref(&l->lru_node);
656 return l->key + round_up(map->key_size, 8);
657 }
658
659 return NULL;
660 }
661
662 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
663 {
664 return __htab_lru_map_lookup_elem(map, key, true);
665 }
666
667 static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
668 {
669 return __htab_lru_map_lookup_elem(map, key, false);
670 }
671
672 static int htab_lru_map_gen_lookup(struct bpf_map *map,
673 struct bpf_insn *insn_buf)
674 {
675 struct bpf_insn *insn = insn_buf;
676 const int ret = BPF_REG_0;
677 const int ref_reg = BPF_REG_1;
678
679 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
680 (void *(*)(struct bpf_map *map, void *key))NULL));
681 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
682 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
683 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
684 offsetof(struct htab_elem, lru_node) +
685 offsetof(struct bpf_lru_node, ref));
686 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
687 *insn++ = BPF_ST_MEM(BPF_B, ret,
688 offsetof(struct htab_elem, lru_node) +
689 offsetof(struct bpf_lru_node, ref),
690 1);
691 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
692 offsetof(struct htab_elem, key) +
693 round_up(map->key_size, 8));
694 return insn - insn_buf;
695 }
696
697 /* It is called from the bpf_lru_list when the LRU needs to delete
698 * older elements from the htab.
699 */
700 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
701 {
702 struct bpf_htab *htab = (struct bpf_htab *)arg;
703 struct htab_elem *l = NULL, *tgt_l;
704 struct hlist_nulls_head *head;
705 struct hlist_nulls_node *n;
706 unsigned long flags;
707 struct bucket *b;
708 int ret;
709
710 tgt_l = container_of(node, struct htab_elem, lru_node);
711 b = __select_bucket(htab, tgt_l->hash);
712 head = &b->head;
713
714 ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
715 if (ret)
716 return false;
717
718 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
719 if (l == tgt_l) {
720 hlist_nulls_del_rcu(&l->hash_node);
721 break;
722 }
723
724 htab_unlock_bucket(htab, b, tgt_l->hash, flags);
725
726 return l == tgt_l;
727 }
728
729 /* Called from syscall */
730 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
731 {
732 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
733 struct hlist_nulls_head *head;
734 struct htab_elem *l, *next_l;
735 u32 hash, key_size;
736 int i = 0;
737
738 WARN_ON_ONCE(!rcu_read_lock_held());
739
740 key_size = map->key_size;
741
742 if (!key)
743 goto find_first_elem;
744
745 hash = htab_map_hash(key, key_size, htab->hashrnd);
746
747 head = select_bucket(htab, hash);
748
749 /* lookup the key */
750 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
751
752 if (!l)
753 goto find_first_elem;
754
755 /* key was found, get next key in the same bucket */
756 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
757 struct htab_elem, hash_node);
758
759 if (next_l) {
760 /* if next elem in this hash list is non-zero, just return it */
761 memcpy(next_key, next_l->key, key_size);
762 return 0;
763 }
764
765 /* no more elements in this hash list, go to the next bucket */
766 i = hash & (htab->n_buckets - 1);
767 i++;
768
769 find_first_elem:
770 /* iterate over buckets */
771 for (; i < htab->n_buckets; i++) {
772 head = select_bucket(htab, i);
773
774 /* pick first element in the bucket */
775 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
776 struct htab_elem, hash_node);
777 if (next_l) {
778 /* if it's not empty, just return it */
779 memcpy(next_key, next_l->key, key_size);
780 return 0;
781 }
782 }
783
784 /* iterated over all buckets and all elements */
785 return -ENOENT;
786 }
787
788 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
789 {
790 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
791 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
792 kfree(l);
793 }
794
795 static void htab_elem_free_rcu(struct rcu_head *head)
796 {
797 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
798 struct bpf_htab *htab = l->htab;
799
800 htab_elem_free(htab, l);
801 }
802
803 static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
804 {
805 struct bpf_map *map = &htab->map;
806 void *ptr;
807
808 if (map->ops->map_fd_put_ptr) {
809 ptr = fd_htab_map_get_ptr(map, l);
810 map->ops->map_fd_put_ptr(ptr);
811 }
812 }
813
814 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
815 {
816 htab_put_fd_value(htab, l);
817
818 if (htab_is_prealloc(htab)) {
819 __pcpu_freelist_push(&htab->freelist, &l->fnode);
820 } else {
821 atomic_dec(&htab->count);
822 l->htab = htab;
823 call_rcu(&l->rcu, htab_elem_free_rcu);
824 }
825 }
826
827 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
828 void *value, bool onallcpus)
829 {
830 if (!onallcpus) {
831 /* copy true value_size bytes */
832 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
833 } else {
834 u32 size = round_up(htab->map.value_size, 8);
835 int off = 0, cpu;
836
837 for_each_possible_cpu(cpu) {
838 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
839 value + off, size);
840 off += size;
841 }
842 }
843 }
844
845 static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
846 void *value, bool onallcpus)
847 {
848 /* When using prealloc and not setting the initial value on all cpus,
849 * zero-fill element values for other cpus (just as what happens when
850 * not using prealloc). Otherwise, bpf program has no way to ensure
851 * known initial values for cpus other than current one
852 * (onallcpus=false always when coming from bpf prog).
853 */
854 if (htab_is_prealloc(htab) && !onallcpus) {
855 u32 size = round_up(htab->map.value_size, 8);
856 int current_cpu = raw_smp_processor_id();
857 int cpu;
858
859 for_each_possible_cpu(cpu) {
860 if (cpu == current_cpu)
861 bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
862 size);
863 else
864 memset(per_cpu_ptr(pptr, cpu), 0, size);
865 }
866 } else {
867 pcpu_copy_value(htab, pptr, value, onallcpus);
868 }
869 }
870
871 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
872 {
873 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
874 BITS_PER_LONG == 64;
875 }
876
877 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
878 void *value, u32 key_size, u32 hash,
879 bool percpu, bool onallcpus,
880 struct htab_elem *old_elem)
881 {
882 u32 size = htab->map.value_size;
883 bool prealloc = htab_is_prealloc(htab);
884 struct htab_elem *l_new, **pl_new;
885 void __percpu *pptr;
886
887 if (prealloc) {
888 if (old_elem) {
889 /* if we're updating the existing element,
890 * use per-cpu extra elems to avoid freelist_pop/push
891 */
892 pl_new = this_cpu_ptr(htab->extra_elems);
893 l_new = *pl_new;
894 htab_put_fd_value(htab, old_elem);
895 *pl_new = old_elem;
896 } else {
897 struct pcpu_freelist_node *l;
898
899 l = __pcpu_freelist_pop(&htab->freelist);
900 if (!l)
901 return ERR_PTR(-E2BIG);
902 l_new = container_of(l, struct htab_elem, fnode);
903 }
904 } else {
905 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
906 if (!old_elem) {
907 /* when map is full and update() is replacing
908 * old element, it's ok to allocate, since
909 * old element will be freed immediately.
910 * Otherwise return an error
911 */
912 l_new = ERR_PTR(-E2BIG);
913 goto dec_count;
914 }
915 l_new = bpf_map_kmalloc_node(&htab->map, htab->elem_size,
916 GFP_ATOMIC | __GFP_NOWARN,
917 htab->map.numa_node);
918 if (!l_new) {
919 l_new = ERR_PTR(-ENOMEM);
920 goto dec_count;
921 }
922 check_and_init_map_lock(&htab->map,
923 l_new->key + round_up(key_size, 8));
924 }
925
926 memcpy(l_new->key, key, key_size);
927 if (percpu) {
928 size = round_up(size, 8);
929 if (prealloc) {
930 pptr = htab_elem_get_ptr(l_new, key_size);
931 } else {
932 /* alloc_percpu zero-fills */
933 pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
934 GFP_ATOMIC | __GFP_NOWARN);
935 if (!pptr) {
936 kfree(l_new);
937 l_new = ERR_PTR(-ENOMEM);
938 goto dec_count;
939 }
940 }
941
942 pcpu_init_value(htab, pptr, value, onallcpus);
943
944 if (!prealloc)
945 htab_elem_set_ptr(l_new, key_size, pptr);
946 } else if (fd_htab_map_needs_adjust(htab)) {
947 size = round_up(size, 8);
948 memcpy(l_new->key + round_up(key_size, 8), value, size);
949 } else {
950 copy_map_value(&htab->map,
951 l_new->key + round_up(key_size, 8),
952 value);
953 }
954
955 l_new->hash = hash;
956 return l_new;
957 dec_count:
958 atomic_dec(&htab->count);
959 return l_new;
960 }
961
962 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
963 u64 map_flags)
964 {
965 if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
966 /* elem already exists */
967 return -EEXIST;
968
969 if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
970 /* elem doesn't exist, cannot update it */
971 return -ENOENT;
972
973 return 0;
974 }
975
976 /* Called from syscall or from eBPF program */
977 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
978 u64 map_flags)
979 {
980 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
981 struct htab_elem *l_new = NULL, *l_old;
982 struct hlist_nulls_head *head;
983 unsigned long flags;
984 struct bucket *b;
985 u32 key_size, hash;
986 int ret;
987
988 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
989 /* unknown flags */
990 return -EINVAL;
991
992 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
993
994 key_size = map->key_size;
995
996 hash = htab_map_hash(key, key_size, htab->hashrnd);
997
998 b = __select_bucket(htab, hash);
999 head = &b->head;
1000
1001 if (unlikely(map_flags & BPF_F_LOCK)) {
1002 if (unlikely(!map_value_has_spin_lock(map)))
1003 return -EINVAL;
1004 /* find an element without taking the bucket lock */
1005 l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
1006 htab->n_buckets);
1007 ret = check_flags(htab, l_old, map_flags);
1008 if (ret)
1009 return ret;
1010 if (l_old) {
1011 /* grab the element lock and update value in place */
1012 copy_map_value_locked(map,
1013 l_old->key + round_up(key_size, 8),
1014 value, false);
1015 return 0;
1016 }
1017 /* fall through, grab the bucket lock and lookup again.
1018 * 99.9% chance that the element won't be found,
1019 * but second lookup under lock has to be done.
1020 */
1021 }
1022
1023 ret = htab_lock_bucket(htab, b, hash, &flags);
1024 if (ret)
1025 return ret;
1026
1027 l_old = lookup_elem_raw(head, hash, key, key_size);
1028
1029 ret = check_flags(htab, l_old, map_flags);
1030 if (ret)
1031 goto err;
1032
1033 if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
1034 /* first lookup without the bucket lock didn't find the element,
1035 * but second lookup with the bucket lock found it.
1036 * This case is highly unlikely, but has to be dealt with:
1037 * grab the element lock in addition to the bucket lock
1038 * and update element in place
1039 */
1040 copy_map_value_locked(map,
1041 l_old->key + round_up(key_size, 8),
1042 value, false);
1043 ret = 0;
1044 goto err;
1045 }
1046
1047 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
1048 l_old);
1049 if (IS_ERR(l_new)) {
1050 /* all pre-allocated elements are in use or memory exhausted */
1051 ret = PTR_ERR(l_new);
1052 goto err;
1053 }
1054
1055 /* add new element to the head of the list, so that
1056 * concurrent search will find it before old elem
1057 */
1058 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1059 if (l_old) {
1060 hlist_nulls_del_rcu(&l_old->hash_node);
1061 if (!htab_is_prealloc(htab))
1062 free_htab_elem(htab, l_old);
1063 }
1064 ret = 0;
1065 err:
1066 htab_unlock_bucket(htab, b, hash, flags);
1067 return ret;
1068 }
1069
1070 static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1071 u64 map_flags)
1072 {
1073 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1074 struct htab_elem *l_new, *l_old = NULL;
1075 struct hlist_nulls_head *head;
1076 unsigned long flags;
1077 struct bucket *b;
1078 u32 key_size, hash;
1079 int ret;
1080
1081 if (unlikely(map_flags > BPF_EXIST))
1082 /* unknown flags */
1083 return -EINVAL;
1084
1085 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
1086
1087 key_size = map->key_size;
1088
1089 hash = htab_map_hash(key, key_size, htab->hashrnd);
1090
1091 b = __select_bucket(htab, hash);
1092 head = &b->head;
1093
1094 /* For LRU, we need to alloc before taking bucket's
1095 * spinlock because getting free nodes from LRU may need
1096 * to remove older elements from htab and this removal
1097 * operation will need a bucket lock.
1098 */
1099 l_new = prealloc_lru_pop(htab, key, hash);
1100 if (!l_new)
1101 return -ENOMEM;
1102 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
1103
1104 ret = htab_lock_bucket(htab, b, hash, &flags);
1105 if (ret)
1106 return ret;
1107
1108 l_old = lookup_elem_raw(head, hash, key, key_size);
1109
1110 ret = check_flags(htab, l_old, map_flags);
1111 if (ret)
1112 goto err;
1113
1114 /* add new element to the head of the list, so that
1115 * concurrent search will find it before old elem
1116 */
1117 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1118 if (l_old) {
1119 bpf_lru_node_set_ref(&l_new->lru_node);
1120 hlist_nulls_del_rcu(&l_old->hash_node);
1121 }
1122 ret = 0;
1123
1124 err:
1125 htab_unlock_bucket(htab, b, hash, flags);
1126
1127 if (ret)
1128 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1129 else if (l_old)
1130 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
1131
1132 return ret;
1133 }
1134
1135 static int __htab_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 ret = htab_lock_bucket(htab, b, hash, &flags);
1161 if (ret)
1162 return ret;
1163
1164 l_old = lookup_elem_raw(head, hash, key, key_size);
1165
1166 ret = check_flags(htab, l_old, map_flags);
1167 if (ret)
1168 goto err;
1169
1170 if (l_old) {
1171 /* per-cpu hash map can update value in-place */
1172 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1173 value, onallcpus);
1174 } else {
1175 l_new = alloc_htab_elem(htab, key, value, key_size,
1176 hash, true, onallcpus, NULL);
1177 if (IS_ERR(l_new)) {
1178 ret = PTR_ERR(l_new);
1179 goto err;
1180 }
1181 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1182 }
1183 ret = 0;
1184 err:
1185 htab_unlock_bucket(htab, b, hash, flags);
1186 return ret;
1187 }
1188
1189 static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1190 void *value, u64 map_flags,
1191 bool onallcpus)
1192 {
1193 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1194 struct htab_elem *l_new = NULL, *l_old;
1195 struct hlist_nulls_head *head;
1196 unsigned long flags;
1197 struct bucket *b;
1198 u32 key_size, hash;
1199 int ret;
1200
1201 if (unlikely(map_flags > BPF_EXIST))
1202 /* unknown flags */
1203 return -EINVAL;
1204
1205 WARN_ON_ONCE(!rcu_read_lock_held());
1206
1207 key_size = map->key_size;
1208
1209 hash = htab_map_hash(key, key_size, htab->hashrnd);
1210
1211 b = __select_bucket(htab, hash);
1212 head = &b->head;
1213
1214 /* For LRU, we need to alloc before taking bucket's
1215 * spinlock because LRU's elem alloc may need
1216 * to remove older elem from htab and this removal
1217 * operation will need a bucket lock.
1218 */
1219 if (map_flags != BPF_EXIST) {
1220 l_new = prealloc_lru_pop(htab, key, hash);
1221 if (!l_new)
1222 return -ENOMEM;
1223 }
1224
1225 ret = htab_lock_bucket(htab, b, hash, &flags);
1226 if (ret)
1227 return ret;
1228
1229 l_old = lookup_elem_raw(head, hash, key, key_size);
1230
1231 ret = check_flags(htab, l_old, map_flags);
1232 if (ret)
1233 goto err;
1234
1235 if (l_old) {
1236 bpf_lru_node_set_ref(&l_old->lru_node);
1237
1238 /* per-cpu hash map can update value in-place */
1239 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1240 value, onallcpus);
1241 } else {
1242 pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
1243 value, onallcpus);
1244 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1245 l_new = NULL;
1246 }
1247 ret = 0;
1248 err:
1249 htab_unlock_bucket(htab, b, hash, flags);
1250 if (l_new)
1251 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1252 return ret;
1253 }
1254
1255 static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1256 void *value, u64 map_flags)
1257 {
1258 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1259 }
1260
1261 static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1262 void *value, u64 map_flags)
1263 {
1264 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1265 false);
1266 }
1267
1268 /* Called from syscall or from eBPF program */
1269 static int htab_map_delete_elem(struct bpf_map *map, void *key)
1270 {
1271 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1272 struct hlist_nulls_head *head;
1273 struct bucket *b;
1274 struct htab_elem *l;
1275 unsigned long flags;
1276 u32 hash, key_size;
1277 int ret;
1278
1279 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
1280
1281 key_size = map->key_size;
1282
1283 hash = htab_map_hash(key, key_size, htab->hashrnd);
1284 b = __select_bucket(htab, hash);
1285 head = &b->head;
1286
1287 ret = htab_lock_bucket(htab, b, hash, &flags);
1288 if (ret)
1289 return ret;
1290
1291 l = lookup_elem_raw(head, hash, key, key_size);
1292
1293 if (l) {
1294 hlist_nulls_del_rcu(&l->hash_node);
1295 free_htab_elem(htab, l);
1296 } else {
1297 ret = -ENOENT;
1298 }
1299
1300 htab_unlock_bucket(htab, b, hash, flags);
1301 return ret;
1302 }
1303
1304 static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1305 {
1306 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1307 struct hlist_nulls_head *head;
1308 struct bucket *b;
1309 struct htab_elem *l;
1310 unsigned long flags;
1311 u32 hash, key_size;
1312 int ret;
1313
1314 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
1315
1316 key_size = map->key_size;
1317
1318 hash = htab_map_hash(key, key_size, htab->hashrnd);
1319 b = __select_bucket(htab, hash);
1320 head = &b->head;
1321
1322 ret = htab_lock_bucket(htab, b, hash, &flags);
1323 if (ret)
1324 return ret;
1325
1326 l = lookup_elem_raw(head, hash, key, key_size);
1327
1328 if (l)
1329 hlist_nulls_del_rcu(&l->hash_node);
1330 else
1331 ret = -ENOENT;
1332
1333 htab_unlock_bucket(htab, b, hash, flags);
1334 if (l)
1335 bpf_lru_push_free(&htab->lru, &l->lru_node);
1336 return ret;
1337 }
1338
1339 static void delete_all_elements(struct bpf_htab *htab)
1340 {
1341 int i;
1342
1343 for (i = 0; i < htab->n_buckets; i++) {
1344 struct hlist_nulls_head *head = select_bucket(htab, i);
1345 struct hlist_nulls_node *n;
1346 struct htab_elem *l;
1347
1348 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1349 hlist_nulls_del_rcu(&l->hash_node);
1350 htab_elem_free(htab, l);
1351 }
1352 }
1353 }
1354
1355 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1356 static void htab_map_free(struct bpf_map *map)
1357 {
1358 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1359 int i;
1360
1361 /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
1362 * bpf_free_used_maps() is called after bpf prog is no longer executing.
1363 * There is no need to synchronize_rcu() here to protect map elements.
1364 */
1365
1366 /* some of free_htab_elem() callbacks for elements of this map may
1367 * not have executed. Wait for them.
1368 */
1369 rcu_barrier();
1370 if (!htab_is_prealloc(htab))
1371 delete_all_elements(htab);
1372 else
1373 prealloc_destroy(htab);
1374
1375 free_percpu(htab->extra_elems);
1376 bpf_map_area_free(htab->buckets);
1377 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
1378 free_percpu(htab->map_locked[i]);
1379 lockdep_unregister_key(&htab->lockdep_key);
1380 kfree(htab);
1381 }
1382
1383 static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1384 struct seq_file *m)
1385 {
1386 void *value;
1387
1388 rcu_read_lock();
1389
1390 value = htab_map_lookup_elem(map, key);
1391 if (!value) {
1392 rcu_read_unlock();
1393 return;
1394 }
1395
1396 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1397 seq_puts(m, ": ");
1398 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1399 seq_puts(m, "\n");
1400
1401 rcu_read_unlock();
1402 }
1403
1404 static int
1405 __htab_map_lookup_and_delete_batch(struct bpf_map *map,
1406 const union bpf_attr *attr,
1407 union bpf_attr __user *uattr,
1408 bool do_delete, bool is_lru_map,
1409 bool is_percpu)
1410 {
1411 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1412 u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
1413 void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
1414 void __user *uvalues = u64_to_user_ptr(attr->batch.values);
1415 void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
1416 void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
1417 u32 batch, max_count, size, bucket_size;
1418 struct htab_elem *node_to_free = NULL;
1419 u64 elem_map_flags, map_flags;
1420 struct hlist_nulls_head *head;
1421 struct hlist_nulls_node *n;
1422 unsigned long flags = 0;
1423 bool locked = false;
1424 struct htab_elem *l;
1425 struct bucket *b;
1426 int ret = 0;
1427
1428 elem_map_flags = attr->batch.elem_flags;
1429 if ((elem_map_flags & ~BPF_F_LOCK) ||
1430 ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
1431 return -EINVAL;
1432
1433 map_flags = attr->batch.flags;
1434 if (map_flags)
1435 return -EINVAL;
1436
1437 max_count = attr->batch.count;
1438 if (!max_count)
1439 return 0;
1440
1441 if (put_user(0, &uattr->batch.count))
1442 return -EFAULT;
1443
1444 batch = 0;
1445 if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1446 return -EFAULT;
1447
1448 if (batch >= htab->n_buckets)
1449 return -ENOENT;
1450
1451 key_size = htab->map.key_size;
1452 roundup_key_size = round_up(htab->map.key_size, 8);
1453 value_size = htab->map.value_size;
1454 size = round_up(value_size, 8);
1455 if (is_percpu)
1456 value_size = size * num_possible_cpus();
1457 total = 0;
1458 /* while experimenting with hash tables with sizes ranging from 10 to
1459 * 1000, it was observed that a bucket can have upto 5 entries.
1460 */
1461 bucket_size = 5;
1462
1463 alloc:
1464 /* We cannot do copy_from_user or copy_to_user inside
1465 * the rcu_read_lock. Allocate enough space here.
1466 */
1467 keys = kvmalloc(key_size * bucket_size, GFP_USER | __GFP_NOWARN);
1468 values = kvmalloc(value_size * bucket_size, GFP_USER | __GFP_NOWARN);
1469 if (!keys || !values) {
1470 ret = -ENOMEM;
1471 goto after_loop;
1472 }
1473
1474 again:
1475 bpf_disable_instrumentation();
1476 rcu_read_lock();
1477 again_nocopy:
1478 dst_key = keys;
1479 dst_val = values;
1480 b = &htab->buckets[batch];
1481 head = &b->head;
1482 /* do not grab the lock unless need it (bucket_cnt > 0). */
1483 if (locked) {
1484 ret = htab_lock_bucket(htab, b, batch, &flags);
1485 if (ret)
1486 goto next_batch;
1487 }
1488
1489 bucket_cnt = 0;
1490 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1491 bucket_cnt++;
1492
1493 if (bucket_cnt && !locked) {
1494 locked = true;
1495 goto again_nocopy;
1496 }
1497
1498 if (bucket_cnt > (max_count - total)) {
1499 if (total == 0)
1500 ret = -ENOSPC;
1501 /* Note that since bucket_cnt > 0 here, it is implicit
1502 * that the locked was grabbed, so release it.
1503 */
1504 htab_unlock_bucket(htab, b, batch, flags);
1505 rcu_read_unlock();
1506 bpf_enable_instrumentation();
1507 goto after_loop;
1508 }
1509
1510 if (bucket_cnt > bucket_size) {
1511 bucket_size = bucket_cnt;
1512 /* Note that since bucket_cnt > 0 here, it is implicit
1513 * that the locked was grabbed, so release it.
1514 */
1515 htab_unlock_bucket(htab, b, batch, flags);
1516 rcu_read_unlock();
1517 bpf_enable_instrumentation();
1518 kvfree(keys);
1519 kvfree(values);
1520 goto alloc;
1521 }
1522
1523 /* Next block is only safe to run if you have grabbed the lock */
1524 if (!locked)
1525 goto next_batch;
1526
1527 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1528 memcpy(dst_key, l->key, key_size);
1529
1530 if (is_percpu) {
1531 int off = 0, cpu;
1532 void __percpu *pptr;
1533
1534 pptr = htab_elem_get_ptr(l, map->key_size);
1535 for_each_possible_cpu(cpu) {
1536 bpf_long_memcpy(dst_val + off,
1537 per_cpu_ptr(pptr, cpu), size);
1538 off += size;
1539 }
1540 } else {
1541 value = l->key + roundup_key_size;
1542 if (elem_map_flags & BPF_F_LOCK)
1543 copy_map_value_locked(map, dst_val, value,
1544 true);
1545 else
1546 copy_map_value(map, dst_val, value);
1547 check_and_init_map_lock(map, dst_val);
1548 }
1549 if (do_delete) {
1550 hlist_nulls_del_rcu(&l->hash_node);
1551
1552 /* bpf_lru_push_free() will acquire lru_lock, which
1553 * may cause deadlock. See comments in function
1554 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
1555 * after releasing the bucket lock.
1556 */
1557 if (is_lru_map) {
1558 l->batch_flink = node_to_free;
1559 node_to_free = l;
1560 } else {
1561 free_htab_elem(htab, l);
1562 }
1563 }
1564 dst_key += key_size;
1565 dst_val += value_size;
1566 }
1567
1568 htab_unlock_bucket(htab, b, batch, flags);
1569 locked = false;
1570
1571 while (node_to_free) {
1572 l = node_to_free;
1573 node_to_free = node_to_free->batch_flink;
1574 bpf_lru_push_free(&htab->lru, &l->lru_node);
1575 }
1576
1577 next_batch:
1578 /* If we are not copying data, we can go to next bucket and avoid
1579 * unlocking the rcu.
1580 */
1581 if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1582 batch++;
1583 goto again_nocopy;
1584 }
1585
1586 rcu_read_unlock();
1587 bpf_enable_instrumentation();
1588 if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
1589 key_size * bucket_cnt) ||
1590 copy_to_user(uvalues + total * value_size, values,
1591 value_size * bucket_cnt))) {
1592 ret = -EFAULT;
1593 goto after_loop;
1594 }
1595
1596 total += bucket_cnt;
1597 batch++;
1598 if (batch >= htab->n_buckets) {
1599 ret = -ENOENT;
1600 goto after_loop;
1601 }
1602 goto again;
1603
1604 after_loop:
1605 if (ret == -EFAULT)
1606 goto out;
1607
1608 /* copy # of entries and next batch */
1609 ubatch = u64_to_user_ptr(attr->batch.out_batch);
1610 if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
1611 put_user(total, &uattr->batch.count))
1612 ret = -EFAULT;
1613
1614 out:
1615 kvfree(keys);
1616 kvfree(values);
1617 return ret;
1618 }
1619
1620 static int
1621 htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1622 union bpf_attr __user *uattr)
1623 {
1624 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1625 false, true);
1626 }
1627
1628 static int
1629 htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1630 const union bpf_attr *attr,
1631 union bpf_attr __user *uattr)
1632 {
1633 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1634 false, true);
1635 }
1636
1637 static int
1638 htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1639 union bpf_attr __user *uattr)
1640 {
1641 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1642 false, false);
1643 }
1644
1645 static int
1646 htab_map_lookup_and_delete_batch(struct bpf_map *map,
1647 const union bpf_attr *attr,
1648 union bpf_attr __user *uattr)
1649 {
1650 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1651 false, false);
1652 }
1653
1654 static int
1655 htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1656 const union bpf_attr *attr,
1657 union bpf_attr __user *uattr)
1658 {
1659 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1660 true, true);
1661 }
1662
1663 static int
1664 htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1665 const union bpf_attr *attr,
1666 union bpf_attr __user *uattr)
1667 {
1668 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1669 true, true);
1670 }
1671
1672 static int
1673 htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1674 union bpf_attr __user *uattr)
1675 {
1676 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1677 true, false);
1678 }
1679
1680 static int
1681 htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1682 const union bpf_attr *attr,
1683 union bpf_attr __user *uattr)
1684 {
1685 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1686 true, false);
1687 }
1688
1689 struct bpf_iter_seq_hash_map_info {
1690 struct bpf_map *map;
1691 struct bpf_htab *htab;
1692 void *percpu_value_buf; // non-zero means percpu hash
1693 u32 bucket_id;
1694 u32 skip_elems;
1695 };
1696
1697 static struct htab_elem *
1698 bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1699 struct htab_elem *prev_elem)
1700 {
1701 const struct bpf_htab *htab = info->htab;
1702 u32 skip_elems = info->skip_elems;
1703 u32 bucket_id = info->bucket_id;
1704 struct hlist_nulls_head *head;
1705 struct hlist_nulls_node *n;
1706 struct htab_elem *elem;
1707 struct bucket *b;
1708 u32 i, count;
1709
1710 if (bucket_id >= htab->n_buckets)
1711 return NULL;
1712
1713 /* try to find next elem in the same bucket */
1714 if (prev_elem) {
1715 /* no update/deletion on this bucket, prev_elem should be still valid
1716 * and we won't skip elements.
1717 */
1718 n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
1719 elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
1720 if (elem)
1721 return elem;
1722
1723 /* not found, unlock and go to the next bucket */
1724 b = &htab->buckets[bucket_id++];
1725 rcu_read_unlock();
1726 skip_elems = 0;
1727 }
1728
1729 for (i = bucket_id; i < htab->n_buckets; i++) {
1730 b = &htab->buckets[i];
1731 rcu_read_lock();
1732
1733 count = 0;
1734 head = &b->head;
1735 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
1736 if (count >= skip_elems) {
1737 info->bucket_id = i;
1738 info->skip_elems = count;
1739 return elem;
1740 }
1741 count++;
1742 }
1743
1744 rcu_read_unlock();
1745 skip_elems = 0;
1746 }
1747
1748 info->bucket_id = i;
1749 info->skip_elems = 0;
1750 return NULL;
1751 }
1752
1753 static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
1754 {
1755 struct bpf_iter_seq_hash_map_info *info = seq->private;
1756 struct htab_elem *elem;
1757
1758 elem = bpf_hash_map_seq_find_next(info, NULL);
1759 if (!elem)
1760 return NULL;
1761
1762 if (*pos == 0)
1763 ++*pos;
1764 return elem;
1765 }
1766
1767 static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1768 {
1769 struct bpf_iter_seq_hash_map_info *info = seq->private;
1770
1771 ++*pos;
1772 ++info->skip_elems;
1773 return bpf_hash_map_seq_find_next(info, v);
1774 }
1775
1776 static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
1777 {
1778 struct bpf_iter_seq_hash_map_info *info = seq->private;
1779 u32 roundup_key_size, roundup_value_size;
1780 struct bpf_iter__bpf_map_elem ctx = {};
1781 struct bpf_map *map = info->map;
1782 struct bpf_iter_meta meta;
1783 int ret = 0, off = 0, cpu;
1784 struct bpf_prog *prog;
1785 void __percpu *pptr;
1786
1787 meta.seq = seq;
1788 prog = bpf_iter_get_info(&meta, elem == NULL);
1789 if (prog) {
1790 ctx.meta = &meta;
1791 ctx.map = info->map;
1792 if (elem) {
1793 roundup_key_size = round_up(map->key_size, 8);
1794 ctx.key = elem->key;
1795 if (!info->percpu_value_buf) {
1796 ctx.value = elem->key + roundup_key_size;
1797 } else {
1798 roundup_value_size = round_up(map->value_size, 8);
1799 pptr = htab_elem_get_ptr(elem, map->key_size);
1800 for_each_possible_cpu(cpu) {
1801 bpf_long_memcpy(info->percpu_value_buf + off,
1802 per_cpu_ptr(pptr, cpu),
1803 roundup_value_size);
1804 off += roundup_value_size;
1805 }
1806 ctx.value = info->percpu_value_buf;
1807 }
1808 }
1809 ret = bpf_iter_run_prog(prog, &ctx);
1810 }
1811
1812 return ret;
1813 }
1814
1815 static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
1816 {
1817 return __bpf_hash_map_seq_show(seq, v);
1818 }
1819
1820 static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
1821 {
1822 if (!v)
1823 (void)__bpf_hash_map_seq_show(seq, NULL);
1824 else
1825 rcu_read_unlock();
1826 }
1827
1828 static int bpf_iter_init_hash_map(void *priv_data,
1829 struct bpf_iter_aux_info *aux)
1830 {
1831 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1832 struct bpf_map *map = aux->map;
1833 void *value_buf;
1834 u32 buf_size;
1835
1836 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
1837 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
1838 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
1839 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
1840 if (!value_buf)
1841 return -ENOMEM;
1842
1843 seq_info->percpu_value_buf = value_buf;
1844 }
1845
1846 seq_info->map = map;
1847 seq_info->htab = container_of(map, struct bpf_htab, map);
1848 return 0;
1849 }
1850
1851 static void bpf_iter_fini_hash_map(void *priv_data)
1852 {
1853 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1854
1855 kfree(seq_info->percpu_value_buf);
1856 }
1857
1858 static const struct seq_operations bpf_hash_map_seq_ops = {
1859 .start = bpf_hash_map_seq_start,
1860 .next = bpf_hash_map_seq_next,
1861 .stop = bpf_hash_map_seq_stop,
1862 .show = bpf_hash_map_seq_show,
1863 };
1864
1865 static const struct bpf_iter_seq_info iter_seq_info = {
1866 .seq_ops = &bpf_hash_map_seq_ops,
1867 .init_seq_private = bpf_iter_init_hash_map,
1868 .fini_seq_private = bpf_iter_fini_hash_map,
1869 .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
1870 };
1871
1872 static int htab_map_btf_id;
1873 const struct bpf_map_ops htab_map_ops = {
1874 .map_meta_equal = bpf_map_meta_equal,
1875 .map_alloc_check = htab_map_alloc_check,
1876 .map_alloc = htab_map_alloc,
1877 .map_free = htab_map_free,
1878 .map_get_next_key = htab_map_get_next_key,
1879 .map_lookup_elem = htab_map_lookup_elem,
1880 .map_update_elem = htab_map_update_elem,
1881 .map_delete_elem = htab_map_delete_elem,
1882 .map_gen_lookup = htab_map_gen_lookup,
1883 .map_seq_show_elem = htab_map_seq_show_elem,
1884 BATCH_OPS(htab),
1885 .map_btf_name = "bpf_htab",
1886 .map_btf_id = &htab_map_btf_id,
1887 .iter_seq_info = &iter_seq_info,
1888 };
1889
1890 static int htab_lru_map_btf_id;
1891 const struct bpf_map_ops htab_lru_map_ops = {
1892 .map_meta_equal = bpf_map_meta_equal,
1893 .map_alloc_check = htab_map_alloc_check,
1894 .map_alloc = htab_map_alloc,
1895 .map_free = htab_map_free,
1896 .map_get_next_key = htab_map_get_next_key,
1897 .map_lookup_elem = htab_lru_map_lookup_elem,
1898 .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
1899 .map_update_elem = htab_lru_map_update_elem,
1900 .map_delete_elem = htab_lru_map_delete_elem,
1901 .map_gen_lookup = htab_lru_map_gen_lookup,
1902 .map_seq_show_elem = htab_map_seq_show_elem,
1903 BATCH_OPS(htab_lru),
1904 .map_btf_name = "bpf_htab",
1905 .map_btf_id = &htab_lru_map_btf_id,
1906 .iter_seq_info = &iter_seq_info,
1907 };
1908
1909 /* Called from eBPF program */
1910 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1911 {
1912 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1913
1914 if (l)
1915 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1916 else
1917 return NULL;
1918 }
1919
1920 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1921 {
1922 struct htab_elem *l = __htab_map_lookup_elem(map, key);
1923
1924 if (l) {
1925 bpf_lru_node_set_ref(&l->lru_node);
1926 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1927 }
1928
1929 return NULL;
1930 }
1931
1932 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1933 {
1934 struct htab_elem *l;
1935 void __percpu *pptr;
1936 int ret = -ENOENT;
1937 int cpu, off = 0;
1938 u32 size;
1939
1940 /* per_cpu areas are zero-filled and bpf programs can only
1941 * access 'value_size' of them, so copying rounded areas
1942 * will not leak any kernel data
1943 */
1944 size = round_up(map->value_size, 8);
1945 rcu_read_lock();
1946 l = __htab_map_lookup_elem(map, key);
1947 if (!l)
1948 goto out;
1949 /* We do not mark LRU map element here in order to not mess up
1950 * eviction heuristics when user space does a map walk.
1951 */
1952 pptr = htab_elem_get_ptr(l, map->key_size);
1953 for_each_possible_cpu(cpu) {
1954 bpf_long_memcpy(value + off,
1955 per_cpu_ptr(pptr, cpu), size);
1956 off += size;
1957 }
1958 ret = 0;
1959 out:
1960 rcu_read_unlock();
1961 return ret;
1962 }
1963
1964 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1965 u64 map_flags)
1966 {
1967 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1968 int ret;
1969
1970 rcu_read_lock();
1971 if (htab_is_lru(htab))
1972 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1973 map_flags, true);
1974 else
1975 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1976 true);
1977 rcu_read_unlock();
1978
1979 return ret;
1980 }
1981
1982 static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
1983 struct seq_file *m)
1984 {
1985 struct htab_elem *l;
1986 void __percpu *pptr;
1987 int cpu;
1988
1989 rcu_read_lock();
1990
1991 l = __htab_map_lookup_elem(map, key);
1992 if (!l) {
1993 rcu_read_unlock();
1994 return;
1995 }
1996
1997 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1998 seq_puts(m, ": {\n");
1999 pptr = htab_elem_get_ptr(l, map->key_size);
2000 for_each_possible_cpu(cpu) {
2001 seq_printf(m, "\tcpu%d: ", cpu);
2002 btf_type_seq_show(map->btf, map->btf_value_type_id,
2003 per_cpu_ptr(pptr, cpu), m);
2004 seq_puts(m, "\n");
2005 }
2006 seq_puts(m, "}\n");
2007
2008 rcu_read_unlock();
2009 }
2010
2011 static int htab_percpu_map_btf_id;
2012 const struct bpf_map_ops htab_percpu_map_ops = {
2013 .map_meta_equal = bpf_map_meta_equal,
2014 .map_alloc_check = htab_map_alloc_check,
2015 .map_alloc = htab_map_alloc,
2016 .map_free = htab_map_free,
2017 .map_get_next_key = htab_map_get_next_key,
2018 .map_lookup_elem = htab_percpu_map_lookup_elem,
2019 .map_update_elem = htab_percpu_map_update_elem,
2020 .map_delete_elem = htab_map_delete_elem,
2021 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2022 BATCH_OPS(htab_percpu),
2023 .map_btf_name = "bpf_htab",
2024 .map_btf_id = &htab_percpu_map_btf_id,
2025 .iter_seq_info = &iter_seq_info,
2026 };
2027
2028 static int htab_lru_percpu_map_btf_id;
2029 const struct bpf_map_ops htab_lru_percpu_map_ops = {
2030 .map_meta_equal = bpf_map_meta_equal,
2031 .map_alloc_check = htab_map_alloc_check,
2032 .map_alloc = htab_map_alloc,
2033 .map_free = htab_map_free,
2034 .map_get_next_key = htab_map_get_next_key,
2035 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
2036 .map_update_elem = htab_lru_percpu_map_update_elem,
2037 .map_delete_elem = htab_lru_map_delete_elem,
2038 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2039 BATCH_OPS(htab_lru_percpu),
2040 .map_btf_name = "bpf_htab",
2041 .map_btf_id = &htab_lru_percpu_map_btf_id,
2042 .iter_seq_info = &iter_seq_info,
2043 };
2044
2045 static int fd_htab_map_alloc_check(union bpf_attr *attr)
2046 {
2047 if (attr->value_size != sizeof(u32))
2048 return -EINVAL;
2049 return htab_map_alloc_check(attr);
2050 }
2051
2052 static void fd_htab_map_free(struct bpf_map *map)
2053 {
2054 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2055 struct hlist_nulls_node *n;
2056 struct hlist_nulls_head *head;
2057 struct htab_elem *l;
2058 int i;
2059
2060 for (i = 0; i < htab->n_buckets; i++) {
2061 head = select_bucket(htab, i);
2062
2063 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
2064 void *ptr = fd_htab_map_get_ptr(map, l);
2065
2066 map->ops->map_fd_put_ptr(ptr);
2067 }
2068 }
2069
2070 htab_map_free(map);
2071 }
2072
2073 /* only called from syscall */
2074 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2075 {
2076 void **ptr;
2077 int ret = 0;
2078
2079 if (!map->ops->map_fd_sys_lookup_elem)
2080 return -ENOTSUPP;
2081
2082 rcu_read_lock();
2083 ptr = htab_map_lookup_elem(map, key);
2084 if (ptr)
2085 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2086 else
2087 ret = -ENOENT;
2088 rcu_read_unlock();
2089
2090 return ret;
2091 }
2092
2093 /* only called from syscall */
2094 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2095 void *key, void *value, u64 map_flags)
2096 {
2097 void *ptr;
2098 int ret;
2099 u32 ufd = *(u32 *)value;
2100
2101 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2102 if (IS_ERR(ptr))
2103 return PTR_ERR(ptr);
2104
2105 ret = htab_map_update_elem(map, key, &ptr, map_flags);
2106 if (ret)
2107 map->ops->map_fd_put_ptr(ptr);
2108
2109 return ret;
2110 }
2111
2112 static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2113 {
2114 struct bpf_map *map, *inner_map_meta;
2115
2116 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2117 if (IS_ERR(inner_map_meta))
2118 return inner_map_meta;
2119
2120 map = htab_map_alloc(attr);
2121 if (IS_ERR(map)) {
2122 bpf_map_meta_free(inner_map_meta);
2123 return map;
2124 }
2125
2126 map->inner_map_meta = inner_map_meta;
2127
2128 return map;
2129 }
2130
2131 static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2132 {
2133 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
2134
2135 if (!inner_map)
2136 return NULL;
2137
2138 return READ_ONCE(*inner_map);
2139 }
2140
2141 static int htab_of_map_gen_lookup(struct bpf_map *map,
2142 struct bpf_insn *insn_buf)
2143 {
2144 struct bpf_insn *insn = insn_buf;
2145 const int ret = BPF_REG_0;
2146
2147 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2148 (void *(*)(struct bpf_map *map, void *key))NULL));
2149 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
2150 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2151 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2152 offsetof(struct htab_elem, key) +
2153 round_up(map->key_size, 8));
2154 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2155
2156 return insn - insn_buf;
2157 }
2158
2159 static void htab_of_map_free(struct bpf_map *map)
2160 {
2161 bpf_map_meta_free(map->inner_map_meta);
2162 fd_htab_map_free(map);
2163 }
2164
2165 static int htab_of_maps_map_btf_id;
2166 const struct bpf_map_ops htab_of_maps_map_ops = {
2167 .map_alloc_check = fd_htab_map_alloc_check,
2168 .map_alloc = htab_of_map_alloc,
2169 .map_free = htab_of_map_free,
2170 .map_get_next_key = htab_map_get_next_key,
2171 .map_lookup_elem = htab_of_map_lookup_elem,
2172 .map_delete_elem = htab_map_delete_elem,
2173 .map_fd_get_ptr = bpf_map_fd_get_ptr,
2174 .map_fd_put_ptr = bpf_map_fd_put_ptr,
2175 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2176 .map_gen_lookup = htab_of_map_gen_lookup,
2177 .map_check_btf = map_check_no_btf,
2178 .map_btf_name = "bpf_htab",
2179 .map_btf_id = &htab_of_maps_map_btf_id,
2180 };
Linux with added FPC-III support