Loading...
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};
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 different
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 across 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 paths 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 */
81struct 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
92struct 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 */
110struct 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
130static inline bool htab_is_prealloc(const struct bpf_htab *htab)
131{
132 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
133}
134
135static 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
140static 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
159static 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
183static 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
196static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
197
198static 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
204static 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
210static 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
216static 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
221static 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
226static 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
231static 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 }
246free_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 */
261static 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
276static 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
305skip_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
330free_elems:
331 htab_free_elems(htab);
332 return err;
333}
334
335static 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
345static 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 */
369static 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
432static 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
524free_prealloc:
525 prealloc_destroy(htab);
526free_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);
530free_htab:
531 lockdep_unregister_key(&htab->lockdep_key);
532 kfree(htab);
533 return ERR_PTR(err);
534}
535
536static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
537{
538 return jhash(key, key_len, hashrnd);
539}
540
541static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
542{
543 return &htab->buckets[hash & (htab->n_buckets - 1)];
544}
545
546static 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 */
552static 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 */
569static 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
576again:
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 */
592static 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 !rcu_read_lock_bh_held());
601
602 key_size = map->key_size;
603
604 hash = htab_map_hash(key, key_size, htab->hashrnd);
605
606 head = select_bucket(htab, hash);
607
608 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
609
610 return l;
611}
612
613static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
614{
615 struct htab_elem *l = __htab_map_lookup_elem(map, key);
616
617 if (l)
618 return l->key + round_up(map->key_size, 8);
619
620 return NULL;
621}
622
623/* inline bpf_map_lookup_elem() call.
624 * Instead of:
625 * bpf_prog
626 * bpf_map_lookup_elem
627 * map->ops->map_lookup_elem
628 * htab_map_lookup_elem
629 * __htab_map_lookup_elem
630 * do:
631 * bpf_prog
632 * __htab_map_lookup_elem
633 */
634static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
635{
636 struct bpf_insn *insn = insn_buf;
637 const int ret = BPF_REG_0;
638
639 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
640 (void *(*)(struct bpf_map *map, void *key))NULL));
641 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
642 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
643 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
644 offsetof(struct htab_elem, key) +
645 round_up(map->key_size, 8));
646 return insn - insn_buf;
647}
648
649static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
650 void *key, const bool mark)
651{
652 struct htab_elem *l = __htab_map_lookup_elem(map, key);
653
654 if (l) {
655 if (mark)
656 bpf_lru_node_set_ref(&l->lru_node);
657 return l->key + round_up(map->key_size, 8);
658 }
659
660 return NULL;
661}
662
663static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
664{
665 return __htab_lru_map_lookup_elem(map, key, true);
666}
667
668static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
669{
670 return __htab_lru_map_lookup_elem(map, key, false);
671}
672
673static int htab_lru_map_gen_lookup(struct bpf_map *map,
674 struct bpf_insn *insn_buf)
675{
676 struct bpf_insn *insn = insn_buf;
677 const int ret = BPF_REG_0;
678 const int ref_reg = BPF_REG_1;
679
680 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
681 (void *(*)(struct bpf_map *map, void *key))NULL));
682 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
683 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
684 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
685 offsetof(struct htab_elem, lru_node) +
686 offsetof(struct bpf_lru_node, ref));
687 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
688 *insn++ = BPF_ST_MEM(BPF_B, ret,
689 offsetof(struct htab_elem, lru_node) +
690 offsetof(struct bpf_lru_node, ref),
691 1);
692 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
693 offsetof(struct htab_elem, key) +
694 round_up(map->key_size, 8));
695 return insn - insn_buf;
696}
697
698/* It is called from the bpf_lru_list when the LRU needs to delete
699 * older elements from the htab.
700 */
701static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
702{
703 struct bpf_htab *htab = (struct bpf_htab *)arg;
704 struct htab_elem *l = NULL, *tgt_l;
705 struct hlist_nulls_head *head;
706 struct hlist_nulls_node *n;
707 unsigned long flags;
708 struct bucket *b;
709 int ret;
710
711 tgt_l = container_of(node, struct htab_elem, lru_node);
712 b = __select_bucket(htab, tgt_l->hash);
713 head = &b->head;
714
715 ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
716 if (ret)
717 return false;
718
719 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
720 if (l == tgt_l) {
721 hlist_nulls_del_rcu(&l->hash_node);
722 break;
723 }
724
725 htab_unlock_bucket(htab, b, tgt_l->hash, flags);
726
727 return l == tgt_l;
728}
729
730/* Called from syscall */
731static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
732{
733 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
734 struct hlist_nulls_head *head;
735 struct htab_elem *l, *next_l;
736 u32 hash, key_size;
737 int i = 0;
738
739 WARN_ON_ONCE(!rcu_read_lock_held());
740
741 key_size = map->key_size;
742
743 if (!key)
744 goto find_first_elem;
745
746 hash = htab_map_hash(key, key_size, htab->hashrnd);
747
748 head = select_bucket(htab, hash);
749
750 /* lookup the key */
751 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
752
753 if (!l)
754 goto find_first_elem;
755
756 /* key was found, get next key in the same bucket */
757 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
758 struct htab_elem, hash_node);
759
760 if (next_l) {
761 /* if next elem in this hash list is non-zero, just return it */
762 memcpy(next_key, next_l->key, key_size);
763 return 0;
764 }
765
766 /* no more elements in this hash list, go to the next bucket */
767 i = hash & (htab->n_buckets - 1);
768 i++;
769
770find_first_elem:
771 /* iterate over buckets */
772 for (; i < htab->n_buckets; i++) {
773 head = select_bucket(htab, i);
774
775 /* pick first element in the bucket */
776 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
777 struct htab_elem, hash_node);
778 if (next_l) {
779 /* if it's not empty, just return it */
780 memcpy(next_key, next_l->key, key_size);
781 return 0;
782 }
783 }
784
785 /* iterated over all buckets and all elements */
786 return -ENOENT;
787}
788
789static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
790{
791 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
792 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
793 kfree(l);
794}
795
796static void htab_elem_free_rcu(struct rcu_head *head)
797{
798 struct htab_elem *l = container_of(head, struct htab_elem, rcu);
799 struct bpf_htab *htab = l->htab;
800
801 htab_elem_free(htab, l);
802}
803
804static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
805{
806 struct bpf_map *map = &htab->map;
807 void *ptr;
808
809 if (map->ops->map_fd_put_ptr) {
810 ptr = fd_htab_map_get_ptr(map, l);
811 map->ops->map_fd_put_ptr(ptr);
812 }
813}
814
815static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
816{
817 htab_put_fd_value(htab, l);
818
819 if (htab_is_prealloc(htab)) {
820 __pcpu_freelist_push(&htab->freelist, &l->fnode);
821 } else {
822 atomic_dec(&htab->count);
823 l->htab = htab;
824 call_rcu(&l->rcu, htab_elem_free_rcu);
825 }
826}
827
828static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
829 void *value, bool onallcpus)
830{
831 if (!onallcpus) {
832 /* copy true value_size bytes */
833 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
834 } else {
835 u32 size = round_up(htab->map.value_size, 8);
836 int off = 0, cpu;
837
838 for_each_possible_cpu(cpu) {
839 bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
840 value + off, size);
841 off += size;
842 }
843 }
844}
845
846static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
847 void *value, bool onallcpus)
848{
849 /* When using prealloc and not setting the initial value on all cpus,
850 * zero-fill element values for other cpus (just as what happens when
851 * not using prealloc). Otherwise, bpf program has no way to ensure
852 * known initial values for cpus other than current one
853 * (onallcpus=false always when coming from bpf prog).
854 */
855 if (htab_is_prealloc(htab) && !onallcpus) {
856 u32 size = round_up(htab->map.value_size, 8);
857 int current_cpu = raw_smp_processor_id();
858 int cpu;
859
860 for_each_possible_cpu(cpu) {
861 if (cpu == current_cpu)
862 bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
863 size);
864 else
865 memset(per_cpu_ptr(pptr, cpu), 0, size);
866 }
867 } else {
868 pcpu_copy_value(htab, pptr, value, onallcpus);
869 }
870}
871
872static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
873{
874 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
875 BITS_PER_LONG == 64;
876}
877
878static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
879 void *value, u32 key_size, u32 hash,
880 bool percpu, bool onallcpus,
881 struct htab_elem *old_elem)
882{
883 u32 size = htab->map.value_size;
884 bool prealloc = htab_is_prealloc(htab);
885 struct htab_elem *l_new, **pl_new;
886 void __percpu *pptr;
887
888 if (prealloc) {
889 if (old_elem) {
890 /* if we're updating the existing element,
891 * use per-cpu extra elems to avoid freelist_pop/push
892 */
893 pl_new = this_cpu_ptr(htab->extra_elems);
894 l_new = *pl_new;
895 htab_put_fd_value(htab, old_elem);
896 *pl_new = old_elem;
897 } else {
898 struct pcpu_freelist_node *l;
899
900 l = __pcpu_freelist_pop(&htab->freelist);
901 if (!l)
902 return ERR_PTR(-E2BIG);
903 l_new = container_of(l, struct htab_elem, fnode);
904 }
905 } else {
906 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
907 if (!old_elem) {
908 /* when map is full and update() is replacing
909 * old element, it's ok to allocate, since
910 * old element will be freed immediately.
911 * Otherwise return an error
912 */
913 l_new = ERR_PTR(-E2BIG);
914 goto dec_count;
915 }
916 l_new = bpf_map_kmalloc_node(&htab->map, htab->elem_size,
917 GFP_ATOMIC | __GFP_NOWARN,
918 htab->map.numa_node);
919 if (!l_new) {
920 l_new = ERR_PTR(-ENOMEM);
921 goto dec_count;
922 }
923 check_and_init_map_lock(&htab->map,
924 l_new->key + round_up(key_size, 8));
925 }
926
927 memcpy(l_new->key, key, key_size);
928 if (percpu) {
929 size = round_up(size, 8);
930 if (prealloc) {
931 pptr = htab_elem_get_ptr(l_new, key_size);
932 } else {
933 /* alloc_percpu zero-fills */
934 pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
935 GFP_ATOMIC | __GFP_NOWARN);
936 if (!pptr) {
937 kfree(l_new);
938 l_new = ERR_PTR(-ENOMEM);
939 goto dec_count;
940 }
941 }
942
943 pcpu_init_value(htab, pptr, value, onallcpus);
944
945 if (!prealloc)
946 htab_elem_set_ptr(l_new, key_size, pptr);
947 } else if (fd_htab_map_needs_adjust(htab)) {
948 size = round_up(size, 8);
949 memcpy(l_new->key + round_up(key_size, 8), value, size);
950 } else {
951 copy_map_value(&htab->map,
952 l_new->key + round_up(key_size, 8),
953 value);
954 }
955
956 l_new->hash = hash;
957 return l_new;
958dec_count:
959 atomic_dec(&htab->count);
960 return l_new;
961}
962
963static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
964 u64 map_flags)
965{
966 if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
967 /* elem already exists */
968 return -EEXIST;
969
970 if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
971 /* elem doesn't exist, cannot update it */
972 return -ENOENT;
973
974 return 0;
975}
976
977/* Called from syscall or from eBPF program */
978static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
979 u64 map_flags)
980{
981 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
982 struct htab_elem *l_new = NULL, *l_old;
983 struct hlist_nulls_head *head;
984 unsigned long flags;
985 struct bucket *b;
986 u32 key_size, hash;
987 int ret;
988
989 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
990 /* unknown flags */
991 return -EINVAL;
992
993 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
994 !rcu_read_lock_bh_held());
995
996 key_size = map->key_size;
997
998 hash = htab_map_hash(key, key_size, htab->hashrnd);
999
1000 b = __select_bucket(htab, hash);
1001 head = &b->head;
1002
1003 if (unlikely(map_flags & BPF_F_LOCK)) {
1004 if (unlikely(!map_value_has_spin_lock(map)))
1005 return -EINVAL;
1006 /* find an element without taking the bucket lock */
1007 l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
1008 htab->n_buckets);
1009 ret = check_flags(htab, l_old, map_flags);
1010 if (ret)
1011 return ret;
1012 if (l_old) {
1013 /* grab the element lock and update value in place */
1014 copy_map_value_locked(map,
1015 l_old->key + round_up(key_size, 8),
1016 value, false);
1017 return 0;
1018 }
1019 /* fall through, grab the bucket lock and lookup again.
1020 * 99.9% chance that the element won't be found,
1021 * but second lookup under lock has to be done.
1022 */
1023 }
1024
1025 ret = htab_lock_bucket(htab, b, hash, &flags);
1026 if (ret)
1027 return ret;
1028
1029 l_old = lookup_elem_raw(head, hash, key, key_size);
1030
1031 ret = check_flags(htab, l_old, map_flags);
1032 if (ret)
1033 goto err;
1034
1035 if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
1036 /* first lookup without the bucket lock didn't find the element,
1037 * but second lookup with the bucket lock found it.
1038 * This case is highly unlikely, but has to be dealt with:
1039 * grab the element lock in addition to the bucket lock
1040 * and update element in place
1041 */
1042 copy_map_value_locked(map,
1043 l_old->key + round_up(key_size, 8),
1044 value, false);
1045 ret = 0;
1046 goto err;
1047 }
1048
1049 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
1050 l_old);
1051 if (IS_ERR(l_new)) {
1052 /* all pre-allocated elements are in use or memory exhausted */
1053 ret = PTR_ERR(l_new);
1054 goto err;
1055 }
1056
1057 /* add new element to the head of the list, so that
1058 * concurrent search will find it before old elem
1059 */
1060 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1061 if (l_old) {
1062 hlist_nulls_del_rcu(&l_old->hash_node);
1063 if (!htab_is_prealloc(htab))
1064 free_htab_elem(htab, l_old);
1065 }
1066 ret = 0;
1067err:
1068 htab_unlock_bucket(htab, b, hash, flags);
1069 return ret;
1070}
1071
1072static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1073 u64 map_flags)
1074{
1075 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1076 struct htab_elem *l_new, *l_old = NULL;
1077 struct hlist_nulls_head *head;
1078 unsigned long flags;
1079 struct bucket *b;
1080 u32 key_size, hash;
1081 int ret;
1082
1083 if (unlikely(map_flags > BPF_EXIST))
1084 /* unknown flags */
1085 return -EINVAL;
1086
1087 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1088 !rcu_read_lock_bh_held());
1089
1090 key_size = map->key_size;
1091
1092 hash = htab_map_hash(key, key_size, htab->hashrnd);
1093
1094 b = __select_bucket(htab, hash);
1095 head = &b->head;
1096
1097 /* For LRU, we need to alloc before taking bucket's
1098 * spinlock because getting free nodes from LRU may need
1099 * to remove older elements from htab and this removal
1100 * operation will need a bucket lock.
1101 */
1102 l_new = prealloc_lru_pop(htab, key, hash);
1103 if (!l_new)
1104 return -ENOMEM;
1105 memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
1106
1107 ret = htab_lock_bucket(htab, b, hash, &flags);
1108 if (ret)
1109 return ret;
1110
1111 l_old = lookup_elem_raw(head, hash, key, key_size);
1112
1113 ret = check_flags(htab, l_old, map_flags);
1114 if (ret)
1115 goto err;
1116
1117 /* add new element to the head of the list, so that
1118 * concurrent search will find it before old elem
1119 */
1120 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1121 if (l_old) {
1122 bpf_lru_node_set_ref(&l_new->lru_node);
1123 hlist_nulls_del_rcu(&l_old->hash_node);
1124 }
1125 ret = 0;
1126
1127err:
1128 htab_unlock_bucket(htab, b, hash, flags);
1129
1130 if (ret)
1131 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1132 else if (l_old)
1133 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
1134
1135 return ret;
1136}
1137
1138static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1139 void *value, u64 map_flags,
1140 bool onallcpus)
1141{
1142 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1143 struct htab_elem *l_new = NULL, *l_old;
1144 struct hlist_nulls_head *head;
1145 unsigned long flags;
1146 struct bucket *b;
1147 u32 key_size, hash;
1148 int ret;
1149
1150 if (unlikely(map_flags > BPF_EXIST))
1151 /* unknown flags */
1152 return -EINVAL;
1153
1154 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1155 !rcu_read_lock_bh_held());
1156
1157 key_size = map->key_size;
1158
1159 hash = htab_map_hash(key, key_size, htab->hashrnd);
1160
1161 b = __select_bucket(htab, hash);
1162 head = &b->head;
1163
1164 ret = htab_lock_bucket(htab, b, hash, &flags);
1165 if (ret)
1166 return ret;
1167
1168 l_old = lookup_elem_raw(head, hash, key, key_size);
1169
1170 ret = check_flags(htab, l_old, map_flags);
1171 if (ret)
1172 goto err;
1173
1174 if (l_old) {
1175 /* per-cpu hash map can update value in-place */
1176 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1177 value, onallcpus);
1178 } else {
1179 l_new = alloc_htab_elem(htab, key, value, key_size,
1180 hash, true, onallcpus, NULL);
1181 if (IS_ERR(l_new)) {
1182 ret = PTR_ERR(l_new);
1183 goto err;
1184 }
1185 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1186 }
1187 ret = 0;
1188err:
1189 htab_unlock_bucket(htab, b, hash, flags);
1190 return ret;
1191}
1192
1193static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1194 void *value, u64 map_flags,
1195 bool onallcpus)
1196{
1197 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1198 struct htab_elem *l_new = NULL, *l_old;
1199 struct hlist_nulls_head *head;
1200 unsigned long flags;
1201 struct bucket *b;
1202 u32 key_size, hash;
1203 int ret;
1204
1205 if (unlikely(map_flags > BPF_EXIST))
1206 /* unknown flags */
1207 return -EINVAL;
1208
1209 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1210 !rcu_read_lock_bh_held());
1211
1212 key_size = map->key_size;
1213
1214 hash = htab_map_hash(key, key_size, htab->hashrnd);
1215
1216 b = __select_bucket(htab, hash);
1217 head = &b->head;
1218
1219 /* For LRU, we need to alloc before taking bucket's
1220 * spinlock because LRU's elem alloc may need
1221 * to remove older elem from htab and this removal
1222 * operation will need a bucket lock.
1223 */
1224 if (map_flags != BPF_EXIST) {
1225 l_new = prealloc_lru_pop(htab, key, hash);
1226 if (!l_new)
1227 return -ENOMEM;
1228 }
1229
1230 ret = htab_lock_bucket(htab, b, hash, &flags);
1231 if (ret)
1232 return ret;
1233
1234 l_old = lookup_elem_raw(head, hash, key, key_size);
1235
1236 ret = check_flags(htab, l_old, map_flags);
1237 if (ret)
1238 goto err;
1239
1240 if (l_old) {
1241 bpf_lru_node_set_ref(&l_old->lru_node);
1242
1243 /* per-cpu hash map can update value in-place */
1244 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1245 value, onallcpus);
1246 } else {
1247 pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
1248 value, onallcpus);
1249 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1250 l_new = NULL;
1251 }
1252 ret = 0;
1253err:
1254 htab_unlock_bucket(htab, b, hash, flags);
1255 if (l_new)
1256 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1257 return ret;
1258}
1259
1260static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1261 void *value, u64 map_flags)
1262{
1263 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1264}
1265
1266static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1267 void *value, u64 map_flags)
1268{
1269 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1270 false);
1271}
1272
1273/* Called from syscall or from eBPF program */
1274static int htab_map_delete_elem(struct bpf_map *map, void *key)
1275{
1276 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1277 struct hlist_nulls_head *head;
1278 struct bucket *b;
1279 struct htab_elem *l;
1280 unsigned long flags;
1281 u32 hash, key_size;
1282 int ret;
1283
1284 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1285 !rcu_read_lock_bh_held());
1286
1287 key_size = map->key_size;
1288
1289 hash = htab_map_hash(key, key_size, htab->hashrnd);
1290 b = __select_bucket(htab, hash);
1291 head = &b->head;
1292
1293 ret = htab_lock_bucket(htab, b, hash, &flags);
1294 if (ret)
1295 return ret;
1296
1297 l = lookup_elem_raw(head, hash, key, key_size);
1298
1299 if (l) {
1300 hlist_nulls_del_rcu(&l->hash_node);
1301 free_htab_elem(htab, l);
1302 } else {
1303 ret = -ENOENT;
1304 }
1305
1306 htab_unlock_bucket(htab, b, hash, flags);
1307 return ret;
1308}
1309
1310static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1311{
1312 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1313 struct hlist_nulls_head *head;
1314 struct bucket *b;
1315 struct htab_elem *l;
1316 unsigned long flags;
1317 u32 hash, key_size;
1318 int ret;
1319
1320 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1321 !rcu_read_lock_bh_held());
1322
1323 key_size = map->key_size;
1324
1325 hash = htab_map_hash(key, key_size, htab->hashrnd);
1326 b = __select_bucket(htab, hash);
1327 head = &b->head;
1328
1329 ret = htab_lock_bucket(htab, b, hash, &flags);
1330 if (ret)
1331 return ret;
1332
1333 l = lookup_elem_raw(head, hash, key, key_size);
1334
1335 if (l)
1336 hlist_nulls_del_rcu(&l->hash_node);
1337 else
1338 ret = -ENOENT;
1339
1340 htab_unlock_bucket(htab, b, hash, flags);
1341 if (l)
1342 bpf_lru_push_free(&htab->lru, &l->lru_node);
1343 return ret;
1344}
1345
1346static void delete_all_elements(struct bpf_htab *htab)
1347{
1348 int i;
1349
1350 for (i = 0; i < htab->n_buckets; i++) {
1351 struct hlist_nulls_head *head = select_bucket(htab, i);
1352 struct hlist_nulls_node *n;
1353 struct htab_elem *l;
1354
1355 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1356 hlist_nulls_del_rcu(&l->hash_node);
1357 htab_elem_free(htab, l);
1358 }
1359 }
1360}
1361
1362/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1363static void htab_map_free(struct bpf_map *map)
1364{
1365 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1366 int i;
1367
1368 /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
1369 * bpf_free_used_maps() is called after bpf prog is no longer executing.
1370 * There is no need to synchronize_rcu() here to protect map elements.
1371 */
1372
1373 /* some of free_htab_elem() callbacks for elements of this map may
1374 * not have executed. Wait for them.
1375 */
1376 rcu_barrier();
1377 if (!htab_is_prealloc(htab))
1378 delete_all_elements(htab);
1379 else
1380 prealloc_destroy(htab);
1381
1382 free_percpu(htab->extra_elems);
1383 bpf_map_area_free(htab->buckets);
1384 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
1385 free_percpu(htab->map_locked[i]);
1386 lockdep_unregister_key(&htab->lockdep_key);
1387 kfree(htab);
1388}
1389
1390static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1391 struct seq_file *m)
1392{
1393 void *value;
1394
1395 rcu_read_lock();
1396
1397 value = htab_map_lookup_elem(map, key);
1398 if (!value) {
1399 rcu_read_unlock();
1400 return;
1401 }
1402
1403 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1404 seq_puts(m, ": ");
1405 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1406 seq_puts(m, "\n");
1407
1408 rcu_read_unlock();
1409}
1410
1411static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1412 void *value, bool is_lru_map,
1413 bool is_percpu, u64 flags)
1414{
1415 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1416 struct hlist_nulls_head *head;
1417 unsigned long bflags;
1418 struct htab_elem *l;
1419 u32 hash, key_size;
1420 struct bucket *b;
1421 int ret;
1422
1423 key_size = map->key_size;
1424
1425 hash = htab_map_hash(key, key_size, htab->hashrnd);
1426 b = __select_bucket(htab, hash);
1427 head = &b->head;
1428
1429 ret = htab_lock_bucket(htab, b, hash, &bflags);
1430 if (ret)
1431 return ret;
1432
1433 l = lookup_elem_raw(head, hash, key, key_size);
1434 if (!l) {
1435 ret = -ENOENT;
1436 } else {
1437 if (is_percpu) {
1438 u32 roundup_value_size = round_up(map->value_size, 8);
1439 void __percpu *pptr;
1440 int off = 0, cpu;
1441
1442 pptr = htab_elem_get_ptr(l, key_size);
1443 for_each_possible_cpu(cpu) {
1444 bpf_long_memcpy(value + off,
1445 per_cpu_ptr(pptr, cpu),
1446 roundup_value_size);
1447 off += roundup_value_size;
1448 }
1449 } else {
1450 u32 roundup_key_size = round_up(map->key_size, 8);
1451
1452 if (flags & BPF_F_LOCK)
1453 copy_map_value_locked(map, value, l->key +
1454 roundup_key_size,
1455 true);
1456 else
1457 copy_map_value(map, value, l->key +
1458 roundup_key_size);
1459 check_and_init_map_lock(map, value);
1460 }
1461
1462 hlist_nulls_del_rcu(&l->hash_node);
1463 if (!is_lru_map)
1464 free_htab_elem(htab, l);
1465 }
1466
1467 htab_unlock_bucket(htab, b, hash, bflags);
1468
1469 if (is_lru_map && l)
1470 bpf_lru_push_free(&htab->lru, &l->lru_node);
1471
1472 return ret;
1473}
1474
1475static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1476 void *value, u64 flags)
1477{
1478 return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
1479 flags);
1480}
1481
1482static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1483 void *key, void *value,
1484 u64 flags)
1485{
1486 return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
1487 flags);
1488}
1489
1490static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1491 void *value, u64 flags)
1492{
1493 return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
1494 flags);
1495}
1496
1497static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1498 void *key, void *value,
1499 u64 flags)
1500{
1501 return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
1502 flags);
1503}
1504
1505static int
1506__htab_map_lookup_and_delete_batch(struct bpf_map *map,
1507 const union bpf_attr *attr,
1508 union bpf_attr __user *uattr,
1509 bool do_delete, bool is_lru_map,
1510 bool is_percpu)
1511{
1512 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1513 u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
1514 void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
1515 void __user *uvalues = u64_to_user_ptr(attr->batch.values);
1516 void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
1517 void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
1518 u32 batch, max_count, size, bucket_size;
1519 struct htab_elem *node_to_free = NULL;
1520 u64 elem_map_flags, map_flags;
1521 struct hlist_nulls_head *head;
1522 struct hlist_nulls_node *n;
1523 unsigned long flags = 0;
1524 bool locked = false;
1525 struct htab_elem *l;
1526 struct bucket *b;
1527 int ret = 0;
1528
1529 elem_map_flags = attr->batch.elem_flags;
1530 if ((elem_map_flags & ~BPF_F_LOCK) ||
1531 ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
1532 return -EINVAL;
1533
1534 map_flags = attr->batch.flags;
1535 if (map_flags)
1536 return -EINVAL;
1537
1538 max_count = attr->batch.count;
1539 if (!max_count)
1540 return 0;
1541
1542 if (put_user(0, &uattr->batch.count))
1543 return -EFAULT;
1544
1545 batch = 0;
1546 if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1547 return -EFAULT;
1548
1549 if (batch >= htab->n_buckets)
1550 return -ENOENT;
1551
1552 key_size = htab->map.key_size;
1553 roundup_key_size = round_up(htab->map.key_size, 8);
1554 value_size = htab->map.value_size;
1555 size = round_up(value_size, 8);
1556 if (is_percpu)
1557 value_size = size * num_possible_cpus();
1558 total = 0;
1559 /* while experimenting with hash tables with sizes ranging from 10 to
1560 * 1000, it was observed that a bucket can have upto 5 entries.
1561 */
1562 bucket_size = 5;
1563
1564alloc:
1565 /* We cannot do copy_from_user or copy_to_user inside
1566 * the rcu_read_lock. Allocate enough space here.
1567 */
1568 keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
1569 values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
1570 if (!keys || !values) {
1571 ret = -ENOMEM;
1572 goto after_loop;
1573 }
1574
1575again:
1576 bpf_disable_instrumentation();
1577 rcu_read_lock();
1578again_nocopy:
1579 dst_key = keys;
1580 dst_val = values;
1581 b = &htab->buckets[batch];
1582 head = &b->head;
1583 /* do not grab the lock unless need it (bucket_cnt > 0). */
1584 if (locked) {
1585 ret = htab_lock_bucket(htab, b, batch, &flags);
1586 if (ret)
1587 goto next_batch;
1588 }
1589
1590 bucket_cnt = 0;
1591 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1592 bucket_cnt++;
1593
1594 if (bucket_cnt && !locked) {
1595 locked = true;
1596 goto again_nocopy;
1597 }
1598
1599 if (bucket_cnt > (max_count - total)) {
1600 if (total == 0)
1601 ret = -ENOSPC;
1602 /* Note that since bucket_cnt > 0 here, it is implicit
1603 * that the locked was grabbed, so release it.
1604 */
1605 htab_unlock_bucket(htab, b, batch, flags);
1606 rcu_read_unlock();
1607 bpf_enable_instrumentation();
1608 goto after_loop;
1609 }
1610
1611 if (bucket_cnt > bucket_size) {
1612 bucket_size = bucket_cnt;
1613 /* Note that since bucket_cnt > 0 here, it is implicit
1614 * that the locked was grabbed, so release it.
1615 */
1616 htab_unlock_bucket(htab, b, batch, flags);
1617 rcu_read_unlock();
1618 bpf_enable_instrumentation();
1619 kvfree(keys);
1620 kvfree(values);
1621 goto alloc;
1622 }
1623
1624 /* Next block is only safe to run if you have grabbed the lock */
1625 if (!locked)
1626 goto next_batch;
1627
1628 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1629 memcpy(dst_key, l->key, key_size);
1630
1631 if (is_percpu) {
1632 int off = 0, cpu;
1633 void __percpu *pptr;
1634
1635 pptr = htab_elem_get_ptr(l, map->key_size);
1636 for_each_possible_cpu(cpu) {
1637 bpf_long_memcpy(dst_val + off,
1638 per_cpu_ptr(pptr, cpu), size);
1639 off += size;
1640 }
1641 } else {
1642 value = l->key + roundup_key_size;
1643 if (elem_map_flags & BPF_F_LOCK)
1644 copy_map_value_locked(map, dst_val, value,
1645 true);
1646 else
1647 copy_map_value(map, dst_val, value);
1648 check_and_init_map_lock(map, dst_val);
1649 }
1650 if (do_delete) {
1651 hlist_nulls_del_rcu(&l->hash_node);
1652
1653 /* bpf_lru_push_free() will acquire lru_lock, which
1654 * may cause deadlock. See comments in function
1655 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
1656 * after releasing the bucket lock.
1657 */
1658 if (is_lru_map) {
1659 l->batch_flink = node_to_free;
1660 node_to_free = l;
1661 } else {
1662 free_htab_elem(htab, l);
1663 }
1664 }
1665 dst_key += key_size;
1666 dst_val += value_size;
1667 }
1668
1669 htab_unlock_bucket(htab, b, batch, flags);
1670 locked = false;
1671
1672 while (node_to_free) {
1673 l = node_to_free;
1674 node_to_free = node_to_free->batch_flink;
1675 bpf_lru_push_free(&htab->lru, &l->lru_node);
1676 }
1677
1678next_batch:
1679 /* If we are not copying data, we can go to next bucket and avoid
1680 * unlocking the rcu.
1681 */
1682 if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1683 batch++;
1684 goto again_nocopy;
1685 }
1686
1687 rcu_read_unlock();
1688 bpf_enable_instrumentation();
1689 if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
1690 key_size * bucket_cnt) ||
1691 copy_to_user(uvalues + total * value_size, values,
1692 value_size * bucket_cnt))) {
1693 ret = -EFAULT;
1694 goto after_loop;
1695 }
1696
1697 total += bucket_cnt;
1698 batch++;
1699 if (batch >= htab->n_buckets) {
1700 ret = -ENOENT;
1701 goto after_loop;
1702 }
1703 goto again;
1704
1705after_loop:
1706 if (ret == -EFAULT)
1707 goto out;
1708
1709 /* copy # of entries and next batch */
1710 ubatch = u64_to_user_ptr(attr->batch.out_batch);
1711 if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
1712 put_user(total, &uattr->batch.count))
1713 ret = -EFAULT;
1714
1715out:
1716 kvfree(keys);
1717 kvfree(values);
1718 return ret;
1719}
1720
1721static int
1722htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1723 union bpf_attr __user *uattr)
1724{
1725 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1726 false, true);
1727}
1728
1729static int
1730htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1731 const union bpf_attr *attr,
1732 union bpf_attr __user *uattr)
1733{
1734 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1735 false, true);
1736}
1737
1738static int
1739htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1740 union bpf_attr __user *uattr)
1741{
1742 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1743 false, false);
1744}
1745
1746static int
1747htab_map_lookup_and_delete_batch(struct bpf_map *map,
1748 const union bpf_attr *attr,
1749 union bpf_attr __user *uattr)
1750{
1751 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1752 false, false);
1753}
1754
1755static int
1756htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1757 const union bpf_attr *attr,
1758 union bpf_attr __user *uattr)
1759{
1760 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1761 true, true);
1762}
1763
1764static int
1765htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1766 const union bpf_attr *attr,
1767 union bpf_attr __user *uattr)
1768{
1769 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1770 true, true);
1771}
1772
1773static int
1774htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1775 union bpf_attr __user *uattr)
1776{
1777 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1778 true, false);
1779}
1780
1781static int
1782htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1783 const union bpf_attr *attr,
1784 union bpf_attr __user *uattr)
1785{
1786 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1787 true, false);
1788}
1789
1790struct bpf_iter_seq_hash_map_info {
1791 struct bpf_map *map;
1792 struct bpf_htab *htab;
1793 void *percpu_value_buf; // non-zero means percpu hash
1794 u32 bucket_id;
1795 u32 skip_elems;
1796};
1797
1798static struct htab_elem *
1799bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1800 struct htab_elem *prev_elem)
1801{
1802 const struct bpf_htab *htab = info->htab;
1803 u32 skip_elems = info->skip_elems;
1804 u32 bucket_id = info->bucket_id;
1805 struct hlist_nulls_head *head;
1806 struct hlist_nulls_node *n;
1807 struct htab_elem *elem;
1808 struct bucket *b;
1809 u32 i, count;
1810
1811 if (bucket_id >= htab->n_buckets)
1812 return NULL;
1813
1814 /* try to find next elem in the same bucket */
1815 if (prev_elem) {
1816 /* no update/deletion on this bucket, prev_elem should be still valid
1817 * and we won't skip elements.
1818 */
1819 n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
1820 elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
1821 if (elem)
1822 return elem;
1823
1824 /* not found, unlock and go to the next bucket */
1825 b = &htab->buckets[bucket_id++];
1826 rcu_read_unlock();
1827 skip_elems = 0;
1828 }
1829
1830 for (i = bucket_id; i < htab->n_buckets; i++) {
1831 b = &htab->buckets[i];
1832 rcu_read_lock();
1833
1834 count = 0;
1835 head = &b->head;
1836 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
1837 if (count >= skip_elems) {
1838 info->bucket_id = i;
1839 info->skip_elems = count;
1840 return elem;
1841 }
1842 count++;
1843 }
1844
1845 rcu_read_unlock();
1846 skip_elems = 0;
1847 }
1848
1849 info->bucket_id = i;
1850 info->skip_elems = 0;
1851 return NULL;
1852}
1853
1854static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
1855{
1856 struct bpf_iter_seq_hash_map_info *info = seq->private;
1857 struct htab_elem *elem;
1858
1859 elem = bpf_hash_map_seq_find_next(info, NULL);
1860 if (!elem)
1861 return NULL;
1862
1863 if (*pos == 0)
1864 ++*pos;
1865 return elem;
1866}
1867
1868static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1869{
1870 struct bpf_iter_seq_hash_map_info *info = seq->private;
1871
1872 ++*pos;
1873 ++info->skip_elems;
1874 return bpf_hash_map_seq_find_next(info, v);
1875}
1876
1877static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
1878{
1879 struct bpf_iter_seq_hash_map_info *info = seq->private;
1880 u32 roundup_key_size, roundup_value_size;
1881 struct bpf_iter__bpf_map_elem ctx = {};
1882 struct bpf_map *map = info->map;
1883 struct bpf_iter_meta meta;
1884 int ret = 0, off = 0, cpu;
1885 struct bpf_prog *prog;
1886 void __percpu *pptr;
1887
1888 meta.seq = seq;
1889 prog = bpf_iter_get_info(&meta, elem == NULL);
1890 if (prog) {
1891 ctx.meta = &meta;
1892 ctx.map = info->map;
1893 if (elem) {
1894 roundup_key_size = round_up(map->key_size, 8);
1895 ctx.key = elem->key;
1896 if (!info->percpu_value_buf) {
1897 ctx.value = elem->key + roundup_key_size;
1898 } else {
1899 roundup_value_size = round_up(map->value_size, 8);
1900 pptr = htab_elem_get_ptr(elem, map->key_size);
1901 for_each_possible_cpu(cpu) {
1902 bpf_long_memcpy(info->percpu_value_buf + off,
1903 per_cpu_ptr(pptr, cpu),
1904 roundup_value_size);
1905 off += roundup_value_size;
1906 }
1907 ctx.value = info->percpu_value_buf;
1908 }
1909 }
1910 ret = bpf_iter_run_prog(prog, &ctx);
1911 }
1912
1913 return ret;
1914}
1915
1916static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
1917{
1918 return __bpf_hash_map_seq_show(seq, v);
1919}
1920
1921static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
1922{
1923 if (!v)
1924 (void)__bpf_hash_map_seq_show(seq, NULL);
1925 else
1926 rcu_read_unlock();
1927}
1928
1929static int bpf_iter_init_hash_map(void *priv_data,
1930 struct bpf_iter_aux_info *aux)
1931{
1932 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1933 struct bpf_map *map = aux->map;
1934 void *value_buf;
1935 u32 buf_size;
1936
1937 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
1938 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
1939 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
1940 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
1941 if (!value_buf)
1942 return -ENOMEM;
1943
1944 seq_info->percpu_value_buf = value_buf;
1945 }
1946
1947 seq_info->map = map;
1948 seq_info->htab = container_of(map, struct bpf_htab, map);
1949 return 0;
1950}
1951
1952static void bpf_iter_fini_hash_map(void *priv_data)
1953{
1954 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
1955
1956 kfree(seq_info->percpu_value_buf);
1957}
1958
1959static const struct seq_operations bpf_hash_map_seq_ops = {
1960 .start = bpf_hash_map_seq_start,
1961 .next = bpf_hash_map_seq_next,
1962 .stop = bpf_hash_map_seq_stop,
1963 .show = bpf_hash_map_seq_show,
1964};
1965
1966static const struct bpf_iter_seq_info iter_seq_info = {
1967 .seq_ops = &bpf_hash_map_seq_ops,
1968 .init_seq_private = bpf_iter_init_hash_map,
1969 .fini_seq_private = bpf_iter_fini_hash_map,
1970 .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
1971};
1972
1973static int bpf_for_each_hash_elem(struct bpf_map *map, void *callback_fn,
1974 void *callback_ctx, u64 flags)
1975{
1976 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1977 struct hlist_nulls_head *head;
1978 struct hlist_nulls_node *n;
1979 struct htab_elem *elem;
1980 u32 roundup_key_size;
1981 int i, num_elems = 0;
1982 void __percpu *pptr;
1983 struct bucket *b;
1984 void *key, *val;
1985 bool is_percpu;
1986 u64 ret = 0;
1987
1988 if (flags != 0)
1989 return -EINVAL;
1990
1991 is_percpu = htab_is_percpu(htab);
1992
1993 roundup_key_size = round_up(map->key_size, 8);
1994 /* disable migration so percpu value prepared here will be the
1995 * same as the one seen by the bpf program with bpf_map_lookup_elem().
1996 */
1997 if (is_percpu)
1998 migrate_disable();
1999 for (i = 0; i < htab->n_buckets; i++) {
2000 b = &htab->buckets[i];
2001 rcu_read_lock();
2002 head = &b->head;
2003 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
2004 key = elem->key;
2005 if (is_percpu) {
2006 /* current cpu value for percpu map */
2007 pptr = htab_elem_get_ptr(elem, map->key_size);
2008 val = this_cpu_ptr(pptr);
2009 } else {
2010 val = elem->key + roundup_key_size;
2011 }
2012 num_elems++;
2013 ret = BPF_CAST_CALL(callback_fn)((u64)(long)map,
2014 (u64)(long)key, (u64)(long)val,
2015 (u64)(long)callback_ctx, 0);
2016 /* return value: 0 - continue, 1 - stop and return */
2017 if (ret) {
2018 rcu_read_unlock();
2019 goto out;
2020 }
2021 }
2022 rcu_read_unlock();
2023 }
2024out:
2025 if (is_percpu)
2026 migrate_enable();
2027 return num_elems;
2028}
2029
2030static int htab_map_btf_id;
2031const struct bpf_map_ops htab_map_ops = {
2032 .map_meta_equal = bpf_map_meta_equal,
2033 .map_alloc_check = htab_map_alloc_check,
2034 .map_alloc = htab_map_alloc,
2035 .map_free = htab_map_free,
2036 .map_get_next_key = htab_map_get_next_key,
2037 .map_lookup_elem = htab_map_lookup_elem,
2038 .map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
2039 .map_update_elem = htab_map_update_elem,
2040 .map_delete_elem = htab_map_delete_elem,
2041 .map_gen_lookup = htab_map_gen_lookup,
2042 .map_seq_show_elem = htab_map_seq_show_elem,
2043 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2044 .map_for_each_callback = bpf_for_each_hash_elem,
2045 BATCH_OPS(htab),
2046 .map_btf_name = "bpf_htab",
2047 .map_btf_id = &htab_map_btf_id,
2048 .iter_seq_info = &iter_seq_info,
2049};
2050
2051static int htab_lru_map_btf_id;
2052const struct bpf_map_ops htab_lru_map_ops = {
2053 .map_meta_equal = bpf_map_meta_equal,
2054 .map_alloc_check = htab_map_alloc_check,
2055 .map_alloc = htab_map_alloc,
2056 .map_free = htab_map_free,
2057 .map_get_next_key = htab_map_get_next_key,
2058 .map_lookup_elem = htab_lru_map_lookup_elem,
2059 .map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
2060 .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
2061 .map_update_elem = htab_lru_map_update_elem,
2062 .map_delete_elem = htab_lru_map_delete_elem,
2063 .map_gen_lookup = htab_lru_map_gen_lookup,
2064 .map_seq_show_elem = htab_map_seq_show_elem,
2065 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2066 .map_for_each_callback = bpf_for_each_hash_elem,
2067 BATCH_OPS(htab_lru),
2068 .map_btf_name = "bpf_htab",
2069 .map_btf_id = &htab_lru_map_btf_id,
2070 .iter_seq_info = &iter_seq_info,
2071};
2072
2073/* Called from eBPF program */
2074static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2075{
2076 struct htab_elem *l = __htab_map_lookup_elem(map, key);
2077
2078 if (l)
2079 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2080 else
2081 return NULL;
2082}
2083
2084static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2085{
2086 struct htab_elem *l = __htab_map_lookup_elem(map, key);
2087
2088 if (l) {
2089 bpf_lru_node_set_ref(&l->lru_node);
2090 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2091 }
2092
2093 return NULL;
2094}
2095
2096int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
2097{
2098 struct htab_elem *l;
2099 void __percpu *pptr;
2100 int ret = -ENOENT;
2101 int cpu, off = 0;
2102 u32 size;
2103
2104 /* per_cpu areas are zero-filled and bpf programs can only
2105 * access 'value_size' of them, so copying rounded areas
2106 * will not leak any kernel data
2107 */
2108 size = round_up(map->value_size, 8);
2109 rcu_read_lock();
2110 l = __htab_map_lookup_elem(map, key);
2111 if (!l)
2112 goto out;
2113 /* We do not mark LRU map element here in order to not mess up
2114 * eviction heuristics when user space does a map walk.
2115 */
2116 pptr = htab_elem_get_ptr(l, map->key_size);
2117 for_each_possible_cpu(cpu) {
2118 bpf_long_memcpy(value + off,
2119 per_cpu_ptr(pptr, cpu), size);
2120 off += size;
2121 }
2122 ret = 0;
2123out:
2124 rcu_read_unlock();
2125 return ret;
2126}
2127
2128int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
2129 u64 map_flags)
2130{
2131 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2132 int ret;
2133
2134 rcu_read_lock();
2135 if (htab_is_lru(htab))
2136 ret = __htab_lru_percpu_map_update_elem(map, key, value,
2137 map_flags, true);
2138 else
2139 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
2140 true);
2141 rcu_read_unlock();
2142
2143 return ret;
2144}
2145
2146static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
2147 struct seq_file *m)
2148{
2149 struct htab_elem *l;
2150 void __percpu *pptr;
2151 int cpu;
2152
2153 rcu_read_lock();
2154
2155 l = __htab_map_lookup_elem(map, key);
2156 if (!l) {
2157 rcu_read_unlock();
2158 return;
2159 }
2160
2161 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
2162 seq_puts(m, ": {\n");
2163 pptr = htab_elem_get_ptr(l, map->key_size);
2164 for_each_possible_cpu(cpu) {
2165 seq_printf(m, "\tcpu%d: ", cpu);
2166 btf_type_seq_show(map->btf, map->btf_value_type_id,
2167 per_cpu_ptr(pptr, cpu), m);
2168 seq_puts(m, "\n");
2169 }
2170 seq_puts(m, "}\n");
2171
2172 rcu_read_unlock();
2173}
2174
2175static int htab_percpu_map_btf_id;
2176const struct bpf_map_ops htab_percpu_map_ops = {
2177 .map_meta_equal = bpf_map_meta_equal,
2178 .map_alloc_check = htab_map_alloc_check,
2179 .map_alloc = htab_map_alloc,
2180 .map_free = htab_map_free,
2181 .map_get_next_key = htab_map_get_next_key,
2182 .map_lookup_elem = htab_percpu_map_lookup_elem,
2183 .map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
2184 .map_update_elem = htab_percpu_map_update_elem,
2185 .map_delete_elem = htab_map_delete_elem,
2186 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2187 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2188 .map_for_each_callback = bpf_for_each_hash_elem,
2189 BATCH_OPS(htab_percpu),
2190 .map_btf_name = "bpf_htab",
2191 .map_btf_id = &htab_percpu_map_btf_id,
2192 .iter_seq_info = &iter_seq_info,
2193};
2194
2195static int htab_lru_percpu_map_btf_id;
2196const struct bpf_map_ops htab_lru_percpu_map_ops = {
2197 .map_meta_equal = bpf_map_meta_equal,
2198 .map_alloc_check = htab_map_alloc_check,
2199 .map_alloc = htab_map_alloc,
2200 .map_free = htab_map_free,
2201 .map_get_next_key = htab_map_get_next_key,
2202 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
2203 .map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
2204 .map_update_elem = htab_lru_percpu_map_update_elem,
2205 .map_delete_elem = htab_lru_map_delete_elem,
2206 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2207 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2208 .map_for_each_callback = bpf_for_each_hash_elem,
2209 BATCH_OPS(htab_lru_percpu),
2210 .map_btf_name = "bpf_htab",
2211 .map_btf_id = &htab_lru_percpu_map_btf_id,
2212 .iter_seq_info = &iter_seq_info,
2213};
2214
2215static int fd_htab_map_alloc_check(union bpf_attr *attr)
2216{
2217 if (attr->value_size != sizeof(u32))
2218 return -EINVAL;
2219 return htab_map_alloc_check(attr);
2220}
2221
2222static void fd_htab_map_free(struct bpf_map *map)
2223{
2224 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2225 struct hlist_nulls_node *n;
2226 struct hlist_nulls_head *head;
2227 struct htab_elem *l;
2228 int i;
2229
2230 for (i = 0; i < htab->n_buckets; i++) {
2231 head = select_bucket(htab, i);
2232
2233 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
2234 void *ptr = fd_htab_map_get_ptr(map, l);
2235
2236 map->ops->map_fd_put_ptr(ptr);
2237 }
2238 }
2239
2240 htab_map_free(map);
2241}
2242
2243/* only called from syscall */
2244int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2245{
2246 void **ptr;
2247 int ret = 0;
2248
2249 if (!map->ops->map_fd_sys_lookup_elem)
2250 return -ENOTSUPP;
2251
2252 rcu_read_lock();
2253 ptr = htab_map_lookup_elem(map, key);
2254 if (ptr)
2255 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2256 else
2257 ret = -ENOENT;
2258 rcu_read_unlock();
2259
2260 return ret;
2261}
2262
2263/* only called from syscall */
2264int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2265 void *key, void *value, u64 map_flags)
2266{
2267 void *ptr;
2268 int ret;
2269 u32 ufd = *(u32 *)value;
2270
2271 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2272 if (IS_ERR(ptr))
2273 return PTR_ERR(ptr);
2274
2275 ret = htab_map_update_elem(map, key, &ptr, map_flags);
2276 if (ret)
2277 map->ops->map_fd_put_ptr(ptr);
2278
2279 return ret;
2280}
2281
2282static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2283{
2284 struct bpf_map *map, *inner_map_meta;
2285
2286 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2287 if (IS_ERR(inner_map_meta))
2288 return inner_map_meta;
2289
2290 map = htab_map_alloc(attr);
2291 if (IS_ERR(map)) {
2292 bpf_map_meta_free(inner_map_meta);
2293 return map;
2294 }
2295
2296 map->inner_map_meta = inner_map_meta;
2297
2298 return map;
2299}
2300
2301static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2302{
2303 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
2304
2305 if (!inner_map)
2306 return NULL;
2307
2308 return READ_ONCE(*inner_map);
2309}
2310
2311static int htab_of_map_gen_lookup(struct bpf_map *map,
2312 struct bpf_insn *insn_buf)
2313{
2314 struct bpf_insn *insn = insn_buf;
2315 const int ret = BPF_REG_0;
2316
2317 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2318 (void *(*)(struct bpf_map *map, void *key))NULL));
2319 *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
2320 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2321 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2322 offsetof(struct htab_elem, key) +
2323 round_up(map->key_size, 8));
2324 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2325
2326 return insn - insn_buf;
2327}
2328
2329static void htab_of_map_free(struct bpf_map *map)
2330{
2331 bpf_map_meta_free(map->inner_map_meta);
2332 fd_htab_map_free(map);
2333}
2334
2335static int htab_of_maps_map_btf_id;
2336const struct bpf_map_ops htab_of_maps_map_ops = {
2337 .map_alloc_check = fd_htab_map_alloc_check,
2338 .map_alloc = htab_of_map_alloc,
2339 .map_free = htab_of_map_free,
2340 .map_get_next_key = htab_map_get_next_key,
2341 .map_lookup_elem = htab_of_map_lookup_elem,
2342 .map_delete_elem = htab_map_delete_elem,
2343 .map_fd_get_ptr = bpf_map_fd_get_ptr,
2344 .map_fd_put_ptr = bpf_map_fd_put_ptr,
2345 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2346 .map_gen_lookup = htab_of_map_gen_lookup,
2347 .map_check_btf = map_check_no_btf,
2348 .map_btf_name = "bpf_htab",
2349 .map_btf_id = &htab_of_maps_map_btf_id,
2350};