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/rcupdate_wait.h>
11 #include <linux/random.h>
12 #include <uapi/linux/btf.h>
13 #include <linux/rcupdate_trace.h>
14 #include <linux/btf_ids.h>
15 #include "percpu_freelist.h"
16 #include "bpf_lru_list.h"
17 #include "map_in_map.h"
18 #include <linux/bpf_mem_alloc.h>
19
20 #define HTAB_CREATE_FLAG_MASK \
21 (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
22 BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
23
24 #define BATCH_OPS(_name) \
25 .map_lookup_batch = \
26 _name##_map_lookup_batch, \
27 .map_lookup_and_delete_batch = \
28 _name##_map_lookup_and_delete_batch, \
29 .map_update_batch = \
30 generic_map_update_batch, \
31 .map_delete_batch = \
32 generic_map_delete_batch
33
34 /*
35 * The bucket lock has two protection scopes:
36 *
37 * 1) Serializing concurrent operations from BPF programs on different
38 * CPUs
39 *
40 * 2) Serializing concurrent operations from BPF programs and sys_bpf()
41 *
42 * BPF programs can execute in any context including perf, kprobes and
43 * tracing. As there are almost no limits where perf, kprobes and tracing
44 * can be invoked from the lock operations need to be protected against
45 * deadlocks. Deadlocks can be caused by recursion and by an invocation in
46 * the lock held section when functions which acquire this lock are invoked
47 * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
48 * variable bpf_prog_active, which prevents BPF programs attached to perf
49 * events, kprobes and tracing to be invoked before the prior invocation
50 * from one of these contexts completed. sys_bpf() uses the same mechanism
51 * by pinning the task to the current CPU and incrementing the recursion
52 * protection across the map operation.
53 *
54 * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
55 * operations like memory allocations (even with GFP_ATOMIC) from atomic
56 * contexts. This is required because even with GFP_ATOMIC the memory
57 * allocator calls into code paths which acquire locks with long held lock
58 * sections. To ensure the deterministic behaviour these locks are regular
59 * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
60 * true atomic contexts on an RT kernel are the low level hardware
61 * handling, scheduling, low level interrupt handling, NMIs etc. None of
62 * these contexts should ever do memory allocations.
63 *
64 * As regular device interrupt handlers and soft interrupts are forced into
65 * thread context, the existing code which does
66 * spin_lock*(); alloc(GFP_ATOMIC); spin_unlock*();
67 * just works.
68 *
69 * In theory the BPF locks could be converted to regular spinlocks as well,
70 * but the bucket locks and percpu_freelist locks can be taken from
71 * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
72 * atomic contexts even on RT. Before the introduction of bpf_mem_alloc,
73 * it is only safe to use raw spinlock for preallocated hash map on a RT kernel,
74 * because there is no memory allocation within the lock held sections. However
75 * after hash map was fully converted to use bpf_mem_alloc, there will be
76 * non-synchronous memory allocation for non-preallocated hash map, so it is
77 * safe to always use raw spinlock for bucket lock.
78 */
79 struct bucket {
80 struct hlist_nulls_head head;
81 raw_spinlock_t raw_lock;
82 };
83
84 #define HASHTAB_MAP_LOCK_COUNT 8
85 #define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
86
87 struct bpf_htab {
88 struct bpf_map map;
89 struct bpf_mem_alloc ma;
90 struct bpf_mem_alloc pcpu_ma;
91 struct bucket *buckets;
92 void *elems;
93 union {
94 struct pcpu_freelist freelist;
95 struct bpf_lru lru;
96 };
97 struct htab_elem *__percpu *extra_elems;
98 /* number of elements in non-preallocated hashtable are kept
99 * in either pcount or count
100 */
101 struct percpu_counter pcount;
102 atomic_t count;
103 bool use_percpu_counter;
104 u32 n_buckets; /* number of hash buckets */
105 u32 elem_size; /* size of each element in bytes */
106 u32 hashrnd;
107 struct lock_class_key lockdep_key;
108 int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
109 };
110
111 /* each htab element is struct htab_elem + key + value */
112 struct htab_elem {
113 union {
114 struct hlist_nulls_node hash_node;
115 struct {
116 void *padding;
117 union {
118 struct pcpu_freelist_node fnode;
119 struct htab_elem *batch_flink;
120 };
121 };
122 };
123 union {
124 /* pointer to per-cpu pointer */
125 void *ptr_to_pptr;
126 struct bpf_lru_node lru_node;
127 };
128 u32 hash;
129 char key[] __aligned(8);
130 };
131
htab_is_prealloc(const struct bpf_htab * htab)132 static inline bool htab_is_prealloc(const struct bpf_htab *htab)
133 {
134 return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
135 }
136
htab_init_buckets(struct bpf_htab * htab)137 static void htab_init_buckets(struct bpf_htab *htab)
138 {
139 unsigned int i;
140
141 for (i = 0; i < htab->n_buckets; i++) {
142 INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
143 raw_spin_lock_init(&htab->buckets[i].raw_lock);
144 lockdep_set_class(&htab->buckets[i].raw_lock,
145 &htab->lockdep_key);
146 cond_resched();
147 }
148 }
149
htab_lock_bucket(const struct bpf_htab * htab,struct bucket * b,u32 hash,unsigned long * pflags)150 static inline int htab_lock_bucket(const struct bpf_htab *htab,
151 struct bucket *b, u32 hash,
152 unsigned long *pflags)
153 {
154 unsigned long flags;
155
156 hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
157
158 preempt_disable();
159 local_irq_save(flags);
160 if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
161 __this_cpu_dec(*(htab->map_locked[hash]));
162 local_irq_restore(flags);
163 preempt_enable();
164 return -EBUSY;
165 }
166
167 raw_spin_lock(&b->raw_lock);
168 *pflags = flags;
169
170 return 0;
171 }
172
htab_unlock_bucket(const struct bpf_htab * htab,struct bucket * b,u32 hash,unsigned long flags)173 static inline void htab_unlock_bucket(const struct bpf_htab *htab,
174 struct bucket *b, u32 hash,
175 unsigned long flags)
176 {
177 hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
178 raw_spin_unlock(&b->raw_lock);
179 __this_cpu_dec(*(htab->map_locked[hash]));
180 local_irq_restore(flags);
181 preempt_enable();
182 }
183
184 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
185
htab_is_lru(const struct bpf_htab * htab)186 static bool htab_is_lru(const struct bpf_htab *htab)
187 {
188 return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
189 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
190 }
191
htab_is_percpu(const struct bpf_htab * htab)192 static bool htab_is_percpu(const struct bpf_htab *htab)
193 {
194 return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
195 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
196 }
197
htab_elem_set_ptr(struct htab_elem * l,u32 key_size,void __percpu * pptr)198 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
199 void __percpu *pptr)
200 {
201 *(void __percpu **)(l->key + key_size) = pptr;
202 }
203
htab_elem_get_ptr(struct htab_elem * l,u32 key_size)204 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
205 {
206 return *(void __percpu **)(l->key + key_size);
207 }
208
fd_htab_map_get_ptr(const struct bpf_map * map,struct htab_elem * l)209 static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
210 {
211 return *(void **)(l->key + roundup(map->key_size, 8));
212 }
213
get_htab_elem(struct bpf_htab * htab,int i)214 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
215 {
216 return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
217 }
218
htab_has_extra_elems(struct bpf_htab * htab)219 static bool htab_has_extra_elems(struct bpf_htab *htab)
220 {
221 return !htab_is_percpu(htab) && !htab_is_lru(htab);
222 }
223
htab_free_prealloced_timers_and_wq(struct bpf_htab * htab)224 static void htab_free_prealloced_timers_and_wq(struct bpf_htab *htab)
225 {
226 u32 num_entries = htab->map.max_entries;
227 int i;
228
229 if (htab_has_extra_elems(htab))
230 num_entries += num_possible_cpus();
231
232 for (i = 0; i < num_entries; i++) {
233 struct htab_elem *elem;
234
235 elem = get_htab_elem(htab, i);
236 if (btf_record_has_field(htab->map.record, BPF_TIMER))
237 bpf_obj_free_timer(htab->map.record,
238 elem->key + round_up(htab->map.key_size, 8));
239 if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
240 bpf_obj_free_workqueue(htab->map.record,
241 elem->key + round_up(htab->map.key_size, 8));
242 cond_resched();
243 }
244 }
245
htab_free_prealloced_fields(struct bpf_htab * htab)246 static void htab_free_prealloced_fields(struct bpf_htab *htab)
247 {
248 u32 num_entries = htab->map.max_entries;
249 int i;
250
251 if (IS_ERR_OR_NULL(htab->map.record))
252 return;
253 if (htab_has_extra_elems(htab))
254 num_entries += num_possible_cpus();
255 for (i = 0; i < num_entries; i++) {
256 struct htab_elem *elem;
257
258 elem = get_htab_elem(htab, i);
259 if (htab_is_percpu(htab)) {
260 void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
261 int cpu;
262
263 for_each_possible_cpu(cpu) {
264 bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
265 cond_resched();
266 }
267 } else {
268 bpf_obj_free_fields(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
269 cond_resched();
270 }
271 cond_resched();
272 }
273 }
274
htab_free_elems(struct bpf_htab * htab)275 static void htab_free_elems(struct bpf_htab *htab)
276 {
277 int i;
278
279 if (!htab_is_percpu(htab))
280 goto free_elems;
281
282 for (i = 0; i < htab->map.max_entries; i++) {
283 void __percpu *pptr;
284
285 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
286 htab->map.key_size);
287 free_percpu(pptr);
288 cond_resched();
289 }
290 free_elems:
291 bpf_map_area_free(htab->elems);
292 }
293
294 /* The LRU list has a lock (lru_lock). Each htab bucket has a lock
295 * (bucket_lock). If both locks need to be acquired together, the lock
296 * order is always lru_lock -> bucket_lock and this only happens in
297 * bpf_lru_list.c logic. For example, certain code path of
298 * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
299 * will acquire lru_lock first followed by acquiring bucket_lock.
300 *
301 * In hashtab.c, to avoid deadlock, lock acquisition of
302 * bucket_lock followed by lru_lock is not allowed. In such cases,
303 * bucket_lock needs to be released first before acquiring lru_lock.
304 */
prealloc_lru_pop(struct bpf_htab * htab,void * key,u32 hash)305 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
306 u32 hash)
307 {
308 struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
309 struct htab_elem *l;
310
311 if (node) {
312 bpf_map_inc_elem_count(&htab->map);
313 l = container_of(node, struct htab_elem, lru_node);
314 memcpy(l->key, key, htab->map.key_size);
315 return l;
316 }
317
318 return NULL;
319 }
320
prealloc_init(struct bpf_htab * htab)321 static int prealloc_init(struct bpf_htab *htab)
322 {
323 u32 num_entries = htab->map.max_entries;
324 int err = -ENOMEM, i;
325
326 if (htab_has_extra_elems(htab))
327 num_entries += num_possible_cpus();
328
329 htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
330 htab->map.numa_node);
331 if (!htab->elems)
332 return -ENOMEM;
333
334 if (!htab_is_percpu(htab))
335 goto skip_percpu_elems;
336
337 for (i = 0; i < num_entries; i++) {
338 u32 size = round_up(htab->map.value_size, 8);
339 void __percpu *pptr;
340
341 pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
342 GFP_USER | __GFP_NOWARN);
343 if (!pptr)
344 goto free_elems;
345 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
346 pptr);
347 cond_resched();
348 }
349
350 skip_percpu_elems:
351 if (htab_is_lru(htab))
352 err = bpf_lru_init(&htab->lru,
353 htab->map.map_flags & BPF_F_NO_COMMON_LRU,
354 offsetof(struct htab_elem, hash) -
355 offsetof(struct htab_elem, lru_node),
356 htab_lru_map_delete_node,
357 htab);
358 else
359 err = pcpu_freelist_init(&htab->freelist);
360
361 if (err)
362 goto free_elems;
363
364 if (htab_is_lru(htab))
365 bpf_lru_populate(&htab->lru, htab->elems,
366 offsetof(struct htab_elem, lru_node),
367 htab->elem_size, num_entries);
368 else
369 pcpu_freelist_populate(&htab->freelist,
370 htab->elems + offsetof(struct htab_elem, fnode),
371 htab->elem_size, num_entries);
372
373 return 0;
374
375 free_elems:
376 htab_free_elems(htab);
377 return err;
378 }
379
prealloc_destroy(struct bpf_htab * htab)380 static void prealloc_destroy(struct bpf_htab *htab)
381 {
382 htab_free_elems(htab);
383
384 if (htab_is_lru(htab))
385 bpf_lru_destroy(&htab->lru);
386 else
387 pcpu_freelist_destroy(&htab->freelist);
388 }
389
alloc_extra_elems(struct bpf_htab * htab)390 static int alloc_extra_elems(struct bpf_htab *htab)
391 {
392 struct htab_elem *__percpu *pptr, *l_new;
393 struct pcpu_freelist_node *l;
394 int cpu;
395
396 pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
397 GFP_USER | __GFP_NOWARN);
398 if (!pptr)
399 return -ENOMEM;
400
401 for_each_possible_cpu(cpu) {
402 l = pcpu_freelist_pop(&htab->freelist);
403 /* pop will succeed, since prealloc_init()
404 * preallocated extra num_possible_cpus elements
405 */
406 l_new = container_of(l, struct htab_elem, fnode);
407 *per_cpu_ptr(pptr, cpu) = l_new;
408 }
409 htab->extra_elems = pptr;
410 return 0;
411 }
412
413 /* Called from syscall */
htab_map_alloc_check(union bpf_attr * attr)414 static int htab_map_alloc_check(union bpf_attr *attr)
415 {
416 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
417 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
418 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
419 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
420 /* percpu_lru means each cpu has its own LRU list.
421 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
422 * the map's value itself is percpu. percpu_lru has
423 * nothing to do with the map's value.
424 */
425 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
426 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
427 bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
428 int numa_node = bpf_map_attr_numa_node(attr);
429
430 BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
431 offsetof(struct htab_elem, hash_node.pprev));
432
433 if (zero_seed && !capable(CAP_SYS_ADMIN))
434 /* Guard against local DoS, and discourage production use. */
435 return -EPERM;
436
437 if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
438 !bpf_map_flags_access_ok(attr->map_flags))
439 return -EINVAL;
440
441 if (!lru && percpu_lru)
442 return -EINVAL;
443
444 if (lru && !prealloc)
445 return -ENOTSUPP;
446
447 if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
448 return -EINVAL;
449
450 /* check sanity of attributes.
451 * value_size == 0 may be allowed in the future to use map as a set
452 */
453 if (attr->max_entries == 0 || attr->key_size == 0 ||
454 attr->value_size == 0)
455 return -EINVAL;
456
457 if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
458 sizeof(struct htab_elem))
459 /* if key_size + value_size is bigger, the user space won't be
460 * able to access the elements via bpf syscall. This check
461 * also makes sure that the elem_size doesn't overflow and it's
462 * kmalloc-able later in htab_map_update_elem()
463 */
464 return -E2BIG;
465
466 return 0;
467 }
468
htab_map_alloc(union bpf_attr * attr)469 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
470 {
471 bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
472 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
473 bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
474 attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
475 /* percpu_lru means each cpu has its own LRU list.
476 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
477 * the map's value itself is percpu. percpu_lru has
478 * nothing to do with the map's value.
479 */
480 bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
481 bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
482 struct bpf_htab *htab;
483 int err, i;
484
485 htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
486 if (!htab)
487 return ERR_PTR(-ENOMEM);
488
489 lockdep_register_key(&htab->lockdep_key);
490
491 bpf_map_init_from_attr(&htab->map, attr);
492
493 if (percpu_lru) {
494 /* ensure each CPU's lru list has >=1 elements.
495 * since we are at it, make each lru list has the same
496 * number of elements.
497 */
498 htab->map.max_entries = roundup(attr->max_entries,
499 num_possible_cpus());
500 if (htab->map.max_entries < attr->max_entries)
501 htab->map.max_entries = rounddown(attr->max_entries,
502 num_possible_cpus());
503 }
504
505 /* hash table size must be power of 2; roundup_pow_of_two() can overflow
506 * into UB on 32-bit arches, so check that first
507 */
508 err = -E2BIG;
509 if (htab->map.max_entries > 1UL << 31)
510 goto free_htab;
511
512 htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
513
514 htab->elem_size = sizeof(struct htab_elem) +
515 round_up(htab->map.key_size, 8);
516 if (percpu)
517 htab->elem_size += sizeof(void *);
518 else
519 htab->elem_size += round_up(htab->map.value_size, 8);
520
521 /* check for u32 overflow */
522 if (htab->n_buckets > U32_MAX / sizeof(struct bucket))
523 goto free_htab;
524
525 err = bpf_map_init_elem_count(&htab->map);
526 if (err)
527 goto free_htab;
528
529 err = -ENOMEM;
530 htab->buckets = bpf_map_area_alloc(htab->n_buckets *
531 sizeof(struct bucket),
532 htab->map.numa_node);
533 if (!htab->buckets)
534 goto free_elem_count;
535
536 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
537 htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
538 sizeof(int),
539 sizeof(int),
540 GFP_USER);
541 if (!htab->map_locked[i])
542 goto free_map_locked;
543 }
544
545 if (htab->map.map_flags & BPF_F_ZERO_SEED)
546 htab->hashrnd = 0;
547 else
548 htab->hashrnd = get_random_u32();
549
550 htab_init_buckets(htab);
551
552 /* compute_batch_value() computes batch value as num_online_cpus() * 2
553 * and __percpu_counter_compare() needs
554 * htab->max_entries - cur_number_of_elems to be more than batch * num_online_cpus()
555 * for percpu_counter to be faster than atomic_t. In practice the average bpf
556 * hash map size is 10k, which means that a system with 64 cpus will fill
557 * hashmap to 20% of 10k before percpu_counter becomes ineffective. Therefore
558 * define our own batch count as 32 then 10k hash map can be filled up to 80%:
559 * 10k - 8k > 32 _batch_ * 64 _cpus_
560 * and __percpu_counter_compare() will still be fast. At that point hash map
561 * collisions will dominate its performance anyway. Assume that hash map filled
562 * to 50+% isn't going to be O(1) and use the following formula to choose
563 * between percpu_counter and atomic_t.
564 */
565 #define PERCPU_COUNTER_BATCH 32
566 if (attr->max_entries / 2 > num_online_cpus() * PERCPU_COUNTER_BATCH)
567 htab->use_percpu_counter = true;
568
569 if (htab->use_percpu_counter) {
570 err = percpu_counter_init(&htab->pcount, 0, GFP_KERNEL);
571 if (err)
572 goto free_map_locked;
573 }
574
575 if (prealloc) {
576 err = prealloc_init(htab);
577 if (err)
578 goto free_map_locked;
579
580 if (!percpu && !lru) {
581 /* lru itself can remove the least used element, so
582 * there is no need for an extra elem during map_update.
583 */
584 err = alloc_extra_elems(htab);
585 if (err)
586 goto free_prealloc;
587 }
588 } else {
589 err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false);
590 if (err)
591 goto free_map_locked;
592 if (percpu) {
593 err = bpf_mem_alloc_init(&htab->pcpu_ma,
594 round_up(htab->map.value_size, 8), true);
595 if (err)
596 goto free_map_locked;
597 }
598 }
599
600 return &htab->map;
601
602 free_prealloc:
603 prealloc_destroy(htab);
604 free_map_locked:
605 if (htab->use_percpu_counter)
606 percpu_counter_destroy(&htab->pcount);
607 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
608 free_percpu(htab->map_locked[i]);
609 bpf_map_area_free(htab->buckets);
610 bpf_mem_alloc_destroy(&htab->pcpu_ma);
611 bpf_mem_alloc_destroy(&htab->ma);
612 free_elem_count:
613 bpf_map_free_elem_count(&htab->map);
614 free_htab:
615 lockdep_unregister_key(&htab->lockdep_key);
616 bpf_map_area_free(htab);
617 return ERR_PTR(err);
618 }
619
htab_map_hash(const void * key,u32 key_len,u32 hashrnd)620 static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
621 {
622 if (likely(key_len % 4 == 0))
623 return jhash2(key, key_len / 4, hashrnd);
624 return jhash(key, key_len, hashrnd);
625 }
626
__select_bucket(struct bpf_htab * htab,u32 hash)627 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
628 {
629 return &htab->buckets[hash & (htab->n_buckets - 1)];
630 }
631
select_bucket(struct bpf_htab * htab,u32 hash)632 static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
633 {
634 return &__select_bucket(htab, hash)->head;
635 }
636
637 /* this lookup function can only be called with bucket lock taken */
lookup_elem_raw(struct hlist_nulls_head * head,u32 hash,void * key,u32 key_size)638 static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
639 void *key, u32 key_size)
640 {
641 struct hlist_nulls_node *n;
642 struct htab_elem *l;
643
644 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
645 if (l->hash == hash && !memcmp(&l->key, key, key_size))
646 return l;
647
648 return NULL;
649 }
650
651 /* can be called without bucket lock. it will repeat the loop in
652 * the unlikely event when elements moved from one bucket into another
653 * while link list is being walked
654 */
lookup_nulls_elem_raw(struct hlist_nulls_head * head,u32 hash,void * key,u32 key_size,u32 n_buckets)655 static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
656 u32 hash, void *key,
657 u32 key_size, u32 n_buckets)
658 {
659 struct hlist_nulls_node *n;
660 struct htab_elem *l;
661
662 again:
663 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
664 if (l->hash == hash && !memcmp(&l->key, key, key_size))
665 return l;
666
667 if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
668 goto again;
669
670 return NULL;
671 }
672
673 /* Called from syscall or from eBPF program directly, so
674 * arguments have to match bpf_map_lookup_elem() exactly.
675 * The return value is adjusted by BPF instructions
676 * in htab_map_gen_lookup().
677 */
__htab_map_lookup_elem(struct bpf_map * map,void * key)678 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
679 {
680 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
681 struct hlist_nulls_head *head;
682 struct htab_elem *l;
683 u32 hash, key_size;
684
685 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
686 !rcu_read_lock_bh_held());
687
688 key_size = map->key_size;
689
690 hash = htab_map_hash(key, key_size, htab->hashrnd);
691
692 head = select_bucket(htab, hash);
693
694 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
695
696 return l;
697 }
698
htab_map_lookup_elem(struct bpf_map * map,void * key)699 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
700 {
701 struct htab_elem *l = __htab_map_lookup_elem(map, key);
702
703 if (l)
704 return l->key + round_up(map->key_size, 8);
705
706 return NULL;
707 }
708
709 /* inline bpf_map_lookup_elem() call.
710 * Instead of:
711 * bpf_prog
712 * bpf_map_lookup_elem
713 * map->ops->map_lookup_elem
714 * htab_map_lookup_elem
715 * __htab_map_lookup_elem
716 * do:
717 * bpf_prog
718 * __htab_map_lookup_elem
719 */
htab_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)720 static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
721 {
722 struct bpf_insn *insn = insn_buf;
723 const int ret = BPF_REG_0;
724
725 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
726 (void *(*)(struct bpf_map *map, void *key))NULL));
727 *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
728 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
729 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
730 offsetof(struct htab_elem, key) +
731 round_up(map->key_size, 8));
732 return insn - insn_buf;
733 }
734
__htab_lru_map_lookup_elem(struct bpf_map * map,void * key,const bool mark)735 static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
736 void *key, const bool mark)
737 {
738 struct htab_elem *l = __htab_map_lookup_elem(map, key);
739
740 if (l) {
741 if (mark)
742 bpf_lru_node_set_ref(&l->lru_node);
743 return l->key + round_up(map->key_size, 8);
744 }
745
746 return NULL;
747 }
748
htab_lru_map_lookup_elem(struct bpf_map * map,void * key)749 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
750 {
751 return __htab_lru_map_lookup_elem(map, key, true);
752 }
753
htab_lru_map_lookup_elem_sys(struct bpf_map * map,void * key)754 static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
755 {
756 return __htab_lru_map_lookup_elem(map, key, false);
757 }
758
htab_lru_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)759 static int htab_lru_map_gen_lookup(struct bpf_map *map,
760 struct bpf_insn *insn_buf)
761 {
762 struct bpf_insn *insn = insn_buf;
763 const int ret = BPF_REG_0;
764 const int ref_reg = BPF_REG_1;
765
766 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
767 (void *(*)(struct bpf_map *map, void *key))NULL));
768 *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
769 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
770 *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
771 offsetof(struct htab_elem, lru_node) +
772 offsetof(struct bpf_lru_node, ref));
773 *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
774 *insn++ = BPF_ST_MEM(BPF_B, ret,
775 offsetof(struct htab_elem, lru_node) +
776 offsetof(struct bpf_lru_node, ref),
777 1);
778 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
779 offsetof(struct htab_elem, key) +
780 round_up(map->key_size, 8));
781 return insn - insn_buf;
782 }
783
check_and_free_fields(struct bpf_htab * htab,struct htab_elem * elem)784 static void check_and_free_fields(struct bpf_htab *htab,
785 struct htab_elem *elem)
786 {
787 if (htab_is_percpu(htab)) {
788 void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
789 int cpu;
790
791 for_each_possible_cpu(cpu)
792 bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
793 } else {
794 void *map_value = elem->key + round_up(htab->map.key_size, 8);
795
796 bpf_obj_free_fields(htab->map.record, map_value);
797 }
798 }
799
800 /* It is called from the bpf_lru_list when the LRU needs to delete
801 * older elements from the htab.
802 */
htab_lru_map_delete_node(void * arg,struct bpf_lru_node * node)803 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
804 {
805 struct bpf_htab *htab = arg;
806 struct htab_elem *l = NULL, *tgt_l;
807 struct hlist_nulls_head *head;
808 struct hlist_nulls_node *n;
809 unsigned long flags;
810 struct bucket *b;
811 int ret;
812
813 tgt_l = container_of(node, struct htab_elem, lru_node);
814 b = __select_bucket(htab, tgt_l->hash);
815 head = &b->head;
816
817 ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
818 if (ret)
819 return false;
820
821 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
822 if (l == tgt_l) {
823 hlist_nulls_del_rcu(&l->hash_node);
824 check_and_free_fields(htab, l);
825 bpf_map_dec_elem_count(&htab->map);
826 break;
827 }
828
829 htab_unlock_bucket(htab, b, tgt_l->hash, flags);
830
831 return l == tgt_l;
832 }
833
834 /* Called from syscall */
htab_map_get_next_key(struct bpf_map * map,void * key,void * next_key)835 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
836 {
837 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
838 struct hlist_nulls_head *head;
839 struct htab_elem *l, *next_l;
840 u32 hash, key_size;
841 int i = 0;
842
843 WARN_ON_ONCE(!rcu_read_lock_held());
844
845 key_size = map->key_size;
846
847 if (!key)
848 goto find_first_elem;
849
850 hash = htab_map_hash(key, key_size, htab->hashrnd);
851
852 head = select_bucket(htab, hash);
853
854 /* lookup the key */
855 l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
856
857 if (!l)
858 goto find_first_elem;
859
860 /* key was found, get next key in the same bucket */
861 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
862 struct htab_elem, hash_node);
863
864 if (next_l) {
865 /* if next elem in this hash list is non-zero, just return it */
866 memcpy(next_key, next_l->key, key_size);
867 return 0;
868 }
869
870 /* no more elements in this hash list, go to the next bucket */
871 i = hash & (htab->n_buckets - 1);
872 i++;
873
874 find_first_elem:
875 /* iterate over buckets */
876 for (; i < htab->n_buckets; i++) {
877 head = select_bucket(htab, i);
878
879 /* pick first element in the bucket */
880 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
881 struct htab_elem, hash_node);
882 if (next_l) {
883 /* if it's not empty, just return it */
884 memcpy(next_key, next_l->key, key_size);
885 return 0;
886 }
887 }
888
889 /* iterated over all buckets and all elements */
890 return -ENOENT;
891 }
892
htab_elem_free(struct bpf_htab * htab,struct htab_elem * l)893 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
894 {
895 check_and_free_fields(htab, l);
896 if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
897 bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr);
898 bpf_mem_cache_free(&htab->ma, l);
899 }
900
htab_put_fd_value(struct bpf_htab * htab,struct htab_elem * l)901 static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
902 {
903 struct bpf_map *map = &htab->map;
904 void *ptr;
905
906 if (map->ops->map_fd_put_ptr) {
907 ptr = fd_htab_map_get_ptr(map, l);
908 map->ops->map_fd_put_ptr(map, ptr, true);
909 }
910 }
911
is_map_full(struct bpf_htab * htab)912 static bool is_map_full(struct bpf_htab *htab)
913 {
914 if (htab->use_percpu_counter)
915 return __percpu_counter_compare(&htab->pcount, htab->map.max_entries,
916 PERCPU_COUNTER_BATCH) >= 0;
917 return atomic_read(&htab->count) >= htab->map.max_entries;
918 }
919
inc_elem_count(struct bpf_htab * htab)920 static void inc_elem_count(struct bpf_htab *htab)
921 {
922 bpf_map_inc_elem_count(&htab->map);
923
924 if (htab->use_percpu_counter)
925 percpu_counter_add_batch(&htab->pcount, 1, PERCPU_COUNTER_BATCH);
926 else
927 atomic_inc(&htab->count);
928 }
929
dec_elem_count(struct bpf_htab * htab)930 static void dec_elem_count(struct bpf_htab *htab)
931 {
932 bpf_map_dec_elem_count(&htab->map);
933
934 if (htab->use_percpu_counter)
935 percpu_counter_add_batch(&htab->pcount, -1, PERCPU_COUNTER_BATCH);
936 else
937 atomic_dec(&htab->count);
938 }
939
940
free_htab_elem(struct bpf_htab * htab,struct htab_elem * l)941 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
942 {
943 htab_put_fd_value(htab, l);
944
945 if (htab_is_prealloc(htab)) {
946 bpf_map_dec_elem_count(&htab->map);
947 check_and_free_fields(htab, l);
948 __pcpu_freelist_push(&htab->freelist, &l->fnode);
949 } else {
950 dec_elem_count(htab);
951 htab_elem_free(htab, l);
952 }
953 }
954
pcpu_copy_value(struct bpf_htab * htab,void __percpu * pptr,void * value,bool onallcpus)955 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
956 void *value, bool onallcpus)
957 {
958 if (!onallcpus) {
959 /* copy true value_size bytes */
960 copy_map_value(&htab->map, this_cpu_ptr(pptr), value);
961 } else {
962 u32 size = round_up(htab->map.value_size, 8);
963 int off = 0, cpu;
964
965 for_each_possible_cpu(cpu) {
966 copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value + off);
967 off += size;
968 }
969 }
970 }
971
pcpu_init_value(struct bpf_htab * htab,void __percpu * pptr,void * value,bool onallcpus)972 static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
973 void *value, bool onallcpus)
974 {
975 /* When not setting the initial value on all cpus, zero-fill element
976 * values for other cpus. Otherwise, bpf program has no way to ensure
977 * known initial values for cpus other than current one
978 * (onallcpus=false always when coming from bpf prog).
979 */
980 if (!onallcpus) {
981 int current_cpu = raw_smp_processor_id();
982 int cpu;
983
984 for_each_possible_cpu(cpu) {
985 if (cpu == current_cpu)
986 copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value);
987 else /* Since elem is preallocated, we cannot touch special fields */
988 zero_map_value(&htab->map, per_cpu_ptr(pptr, cpu));
989 }
990 } else {
991 pcpu_copy_value(htab, pptr, value, onallcpus);
992 }
993 }
994
fd_htab_map_needs_adjust(const struct bpf_htab * htab)995 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
996 {
997 return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
998 BITS_PER_LONG == 64;
999 }
1000
alloc_htab_elem(struct bpf_htab * htab,void * key,void * value,u32 key_size,u32 hash,bool percpu,bool onallcpus,struct htab_elem * old_elem)1001 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
1002 void *value, u32 key_size, u32 hash,
1003 bool percpu, bool onallcpus,
1004 struct htab_elem *old_elem)
1005 {
1006 u32 size = htab->map.value_size;
1007 bool prealloc = htab_is_prealloc(htab);
1008 struct htab_elem *l_new, **pl_new;
1009 void __percpu *pptr;
1010
1011 if (prealloc) {
1012 if (old_elem) {
1013 /* if we're updating the existing element,
1014 * use per-cpu extra elems to avoid freelist_pop/push
1015 */
1016 pl_new = this_cpu_ptr(htab->extra_elems);
1017 l_new = *pl_new;
1018 htab_put_fd_value(htab, old_elem);
1019 *pl_new = old_elem;
1020 } else {
1021 struct pcpu_freelist_node *l;
1022
1023 l = __pcpu_freelist_pop(&htab->freelist);
1024 if (!l)
1025 return ERR_PTR(-E2BIG);
1026 l_new = container_of(l, struct htab_elem, fnode);
1027 bpf_map_inc_elem_count(&htab->map);
1028 }
1029 } else {
1030 if (is_map_full(htab))
1031 if (!old_elem)
1032 /* when map is full and update() is replacing
1033 * old element, it's ok to allocate, since
1034 * old element will be freed immediately.
1035 * Otherwise return an error
1036 */
1037 return ERR_PTR(-E2BIG);
1038 inc_elem_count(htab);
1039 l_new = bpf_mem_cache_alloc(&htab->ma);
1040 if (!l_new) {
1041 l_new = ERR_PTR(-ENOMEM);
1042 goto dec_count;
1043 }
1044 }
1045
1046 memcpy(l_new->key, key, key_size);
1047 if (percpu) {
1048 if (prealloc) {
1049 pptr = htab_elem_get_ptr(l_new, key_size);
1050 } else {
1051 /* alloc_percpu zero-fills */
1052 pptr = bpf_mem_cache_alloc(&htab->pcpu_ma);
1053 if (!pptr) {
1054 bpf_mem_cache_free(&htab->ma, l_new);
1055 l_new = ERR_PTR(-ENOMEM);
1056 goto dec_count;
1057 }
1058 l_new->ptr_to_pptr = pptr;
1059 pptr = *(void **)pptr;
1060 }
1061
1062 pcpu_init_value(htab, pptr, value, onallcpus);
1063
1064 if (!prealloc)
1065 htab_elem_set_ptr(l_new, key_size, pptr);
1066 } else if (fd_htab_map_needs_adjust(htab)) {
1067 size = round_up(size, 8);
1068 memcpy(l_new->key + round_up(key_size, 8), value, size);
1069 } else {
1070 copy_map_value(&htab->map,
1071 l_new->key + round_up(key_size, 8),
1072 value);
1073 }
1074
1075 l_new->hash = hash;
1076 return l_new;
1077 dec_count:
1078 dec_elem_count(htab);
1079 return l_new;
1080 }
1081
check_flags(struct bpf_htab * htab,struct htab_elem * l_old,u64 map_flags)1082 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
1083 u64 map_flags)
1084 {
1085 if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
1086 /* elem already exists */
1087 return -EEXIST;
1088
1089 if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
1090 /* elem doesn't exist, cannot update it */
1091 return -ENOENT;
1092
1093 return 0;
1094 }
1095
1096 /* Called from syscall or from eBPF program */
htab_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)1097 static long htab_map_update_elem(struct bpf_map *map, void *key, void *value,
1098 u64 map_flags)
1099 {
1100 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1101 struct htab_elem *l_new = NULL, *l_old;
1102 struct hlist_nulls_head *head;
1103 unsigned long flags;
1104 struct bucket *b;
1105 u32 key_size, hash;
1106 int ret;
1107
1108 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
1109 /* unknown flags */
1110 return -EINVAL;
1111
1112 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1113 !rcu_read_lock_bh_held());
1114
1115 key_size = map->key_size;
1116
1117 hash = htab_map_hash(key, key_size, htab->hashrnd);
1118
1119 b = __select_bucket(htab, hash);
1120 head = &b->head;
1121
1122 if (unlikely(map_flags & BPF_F_LOCK)) {
1123 if (unlikely(!btf_record_has_field(map->record, BPF_SPIN_LOCK)))
1124 return -EINVAL;
1125 /* find an element without taking the bucket lock */
1126 l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
1127 htab->n_buckets);
1128 ret = check_flags(htab, l_old, map_flags);
1129 if (ret)
1130 return ret;
1131 if (l_old) {
1132 /* grab the element lock and update value in place */
1133 copy_map_value_locked(map,
1134 l_old->key + round_up(key_size, 8),
1135 value, false);
1136 return 0;
1137 }
1138 /* fall through, grab the bucket lock and lookup again.
1139 * 99.9% chance that the element won't be found,
1140 * but second lookup under lock has to be done.
1141 */
1142 }
1143
1144 ret = htab_lock_bucket(htab, b, hash, &flags);
1145 if (ret)
1146 return ret;
1147
1148 l_old = lookup_elem_raw(head, hash, key, key_size);
1149
1150 ret = check_flags(htab, l_old, map_flags);
1151 if (ret)
1152 goto err;
1153
1154 if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
1155 /* first lookup without the bucket lock didn't find the element,
1156 * but second lookup with the bucket lock found it.
1157 * This case is highly unlikely, but has to be dealt with:
1158 * grab the element lock in addition to the bucket lock
1159 * and update element in place
1160 */
1161 copy_map_value_locked(map,
1162 l_old->key + round_up(key_size, 8),
1163 value, false);
1164 ret = 0;
1165 goto err;
1166 }
1167
1168 l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
1169 l_old);
1170 if (IS_ERR(l_new)) {
1171 /* all pre-allocated elements are in use or memory exhausted */
1172 ret = PTR_ERR(l_new);
1173 goto err;
1174 }
1175
1176 /* add new element to the head of the list, so that
1177 * concurrent search will find it before old elem
1178 */
1179 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1180 if (l_old) {
1181 hlist_nulls_del_rcu(&l_old->hash_node);
1182 if (!htab_is_prealloc(htab))
1183 free_htab_elem(htab, l_old);
1184 else
1185 check_and_free_fields(htab, l_old);
1186 }
1187 ret = 0;
1188 err:
1189 htab_unlock_bucket(htab, b, hash, flags);
1190 return ret;
1191 }
1192
htab_lru_push_free(struct bpf_htab * htab,struct htab_elem * elem)1193 static void htab_lru_push_free(struct bpf_htab *htab, struct htab_elem *elem)
1194 {
1195 check_and_free_fields(htab, elem);
1196 bpf_map_dec_elem_count(&htab->map);
1197 bpf_lru_push_free(&htab->lru, &elem->lru_node);
1198 }
1199
htab_lru_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)1200 static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1201 u64 map_flags)
1202 {
1203 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1204 struct htab_elem *l_new, *l_old = NULL;
1205 struct hlist_nulls_head *head;
1206 unsigned long flags;
1207 struct bucket *b;
1208 u32 key_size, hash;
1209 int ret;
1210
1211 if (unlikely(map_flags > BPF_EXIST))
1212 /* unknown flags */
1213 return -EINVAL;
1214
1215 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1216 !rcu_read_lock_bh_held());
1217
1218 key_size = map->key_size;
1219
1220 hash = htab_map_hash(key, key_size, htab->hashrnd);
1221
1222 b = __select_bucket(htab, hash);
1223 head = &b->head;
1224
1225 /* For LRU, we need to alloc before taking bucket's
1226 * spinlock because getting free nodes from LRU may need
1227 * to remove older elements from htab and this removal
1228 * operation will need a bucket lock.
1229 */
1230 l_new = prealloc_lru_pop(htab, key, hash);
1231 if (!l_new)
1232 return -ENOMEM;
1233 copy_map_value(&htab->map,
1234 l_new->key + round_up(map->key_size, 8), value);
1235
1236 ret = htab_lock_bucket(htab, b, hash, &flags);
1237 if (ret)
1238 goto err_lock_bucket;
1239
1240 l_old = lookup_elem_raw(head, hash, key, key_size);
1241
1242 ret = check_flags(htab, l_old, map_flags);
1243 if (ret)
1244 goto err;
1245
1246 /* add new element to the head of the list, so that
1247 * concurrent search will find it before old elem
1248 */
1249 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1250 if (l_old) {
1251 bpf_lru_node_set_ref(&l_new->lru_node);
1252 hlist_nulls_del_rcu(&l_old->hash_node);
1253 }
1254 ret = 0;
1255
1256 err:
1257 htab_unlock_bucket(htab, b, hash, flags);
1258
1259 err_lock_bucket:
1260 if (ret)
1261 htab_lru_push_free(htab, l_new);
1262 else if (l_old)
1263 htab_lru_push_free(htab, l_old);
1264
1265 return ret;
1266 }
1267
__htab_percpu_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags,bool onallcpus)1268 static long __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1269 void *value, u64 map_flags,
1270 bool onallcpus)
1271 {
1272 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1273 struct htab_elem *l_new = NULL, *l_old;
1274 struct hlist_nulls_head *head;
1275 unsigned long flags;
1276 struct bucket *b;
1277 u32 key_size, hash;
1278 int ret;
1279
1280 if (unlikely(map_flags > BPF_EXIST))
1281 /* unknown flags */
1282 return -EINVAL;
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
1291 b = __select_bucket(htab, hash);
1292 head = &b->head;
1293
1294 ret = htab_lock_bucket(htab, b, hash, &flags);
1295 if (ret)
1296 return ret;
1297
1298 l_old = lookup_elem_raw(head, hash, key, key_size);
1299
1300 ret = check_flags(htab, l_old, map_flags);
1301 if (ret)
1302 goto err;
1303
1304 if (l_old) {
1305 /* per-cpu hash map can update value in-place */
1306 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1307 value, onallcpus);
1308 } else {
1309 l_new = alloc_htab_elem(htab, key, value, key_size,
1310 hash, true, onallcpus, NULL);
1311 if (IS_ERR(l_new)) {
1312 ret = PTR_ERR(l_new);
1313 goto err;
1314 }
1315 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1316 }
1317 ret = 0;
1318 err:
1319 htab_unlock_bucket(htab, b, hash, flags);
1320 return ret;
1321 }
1322
__htab_lru_percpu_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags,bool onallcpus)1323 static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1324 void *value, u64 map_flags,
1325 bool onallcpus)
1326 {
1327 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1328 struct htab_elem *l_new = NULL, *l_old;
1329 struct hlist_nulls_head *head;
1330 unsigned long flags;
1331 struct bucket *b;
1332 u32 key_size, hash;
1333 int ret;
1334
1335 if (unlikely(map_flags > BPF_EXIST))
1336 /* unknown flags */
1337 return -EINVAL;
1338
1339 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1340 !rcu_read_lock_bh_held());
1341
1342 key_size = map->key_size;
1343
1344 hash = htab_map_hash(key, key_size, htab->hashrnd);
1345
1346 b = __select_bucket(htab, hash);
1347 head = &b->head;
1348
1349 /* For LRU, we need to alloc before taking bucket's
1350 * spinlock because LRU's elem alloc may need
1351 * to remove older elem from htab and this removal
1352 * operation will need a bucket lock.
1353 */
1354 if (map_flags != BPF_EXIST) {
1355 l_new = prealloc_lru_pop(htab, key, hash);
1356 if (!l_new)
1357 return -ENOMEM;
1358 }
1359
1360 ret = htab_lock_bucket(htab, b, hash, &flags);
1361 if (ret)
1362 goto err_lock_bucket;
1363
1364 l_old = lookup_elem_raw(head, hash, key, key_size);
1365
1366 ret = check_flags(htab, l_old, map_flags);
1367 if (ret)
1368 goto err;
1369
1370 if (l_old) {
1371 bpf_lru_node_set_ref(&l_old->lru_node);
1372
1373 /* per-cpu hash map can update value in-place */
1374 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1375 value, onallcpus);
1376 } else {
1377 pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
1378 value, onallcpus);
1379 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1380 l_new = NULL;
1381 }
1382 ret = 0;
1383 err:
1384 htab_unlock_bucket(htab, b, hash, flags);
1385 err_lock_bucket:
1386 if (l_new) {
1387 bpf_map_dec_elem_count(&htab->map);
1388 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1389 }
1390 return ret;
1391 }
1392
htab_percpu_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)1393 static long htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1394 void *value, u64 map_flags)
1395 {
1396 return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1397 }
1398
htab_lru_percpu_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)1399 static long htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1400 void *value, u64 map_flags)
1401 {
1402 return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1403 false);
1404 }
1405
1406 /* Called from syscall or from eBPF program */
htab_map_delete_elem(struct bpf_map * map,void * key)1407 static long htab_map_delete_elem(struct bpf_map *map, void *key)
1408 {
1409 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1410 struct hlist_nulls_head *head;
1411 struct bucket *b;
1412 struct htab_elem *l;
1413 unsigned long flags;
1414 u32 hash, key_size;
1415 int ret;
1416
1417 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1418 !rcu_read_lock_bh_held());
1419
1420 key_size = map->key_size;
1421
1422 hash = htab_map_hash(key, key_size, htab->hashrnd);
1423 b = __select_bucket(htab, hash);
1424 head = &b->head;
1425
1426 ret = htab_lock_bucket(htab, b, hash, &flags);
1427 if (ret)
1428 return ret;
1429
1430 l = lookup_elem_raw(head, hash, key, key_size);
1431
1432 if (l) {
1433 hlist_nulls_del_rcu(&l->hash_node);
1434 free_htab_elem(htab, l);
1435 } else {
1436 ret = -ENOENT;
1437 }
1438
1439 htab_unlock_bucket(htab, b, hash, flags);
1440 return ret;
1441 }
1442
htab_lru_map_delete_elem(struct bpf_map * map,void * key)1443 static long htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1444 {
1445 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1446 struct hlist_nulls_head *head;
1447 struct bucket *b;
1448 struct htab_elem *l;
1449 unsigned long flags;
1450 u32 hash, key_size;
1451 int ret;
1452
1453 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1454 !rcu_read_lock_bh_held());
1455
1456 key_size = map->key_size;
1457
1458 hash = htab_map_hash(key, key_size, htab->hashrnd);
1459 b = __select_bucket(htab, hash);
1460 head = &b->head;
1461
1462 ret = htab_lock_bucket(htab, b, hash, &flags);
1463 if (ret)
1464 return ret;
1465
1466 l = lookup_elem_raw(head, hash, key, key_size);
1467
1468 if (l)
1469 hlist_nulls_del_rcu(&l->hash_node);
1470 else
1471 ret = -ENOENT;
1472
1473 htab_unlock_bucket(htab, b, hash, flags);
1474 if (l)
1475 htab_lru_push_free(htab, l);
1476 return ret;
1477 }
1478
delete_all_elements(struct bpf_htab * htab)1479 static void delete_all_elements(struct bpf_htab *htab)
1480 {
1481 int i;
1482
1483 /* It's called from a worker thread, so disable migration here,
1484 * since bpf_mem_cache_free() relies on that.
1485 */
1486 migrate_disable();
1487 for (i = 0; i < htab->n_buckets; i++) {
1488 struct hlist_nulls_head *head = select_bucket(htab, i);
1489 struct hlist_nulls_node *n;
1490 struct htab_elem *l;
1491
1492 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1493 hlist_nulls_del_rcu(&l->hash_node);
1494 htab_elem_free(htab, l);
1495 }
1496 cond_resched();
1497 }
1498 migrate_enable();
1499 }
1500
htab_free_malloced_timers_and_wq(struct bpf_htab * htab)1501 static void htab_free_malloced_timers_and_wq(struct bpf_htab *htab)
1502 {
1503 int i;
1504
1505 rcu_read_lock();
1506 for (i = 0; i < htab->n_buckets; i++) {
1507 struct hlist_nulls_head *head = select_bucket(htab, i);
1508 struct hlist_nulls_node *n;
1509 struct htab_elem *l;
1510
1511 hlist_nulls_for_each_entry(l, n, head, hash_node) {
1512 /* We only free timer on uref dropping to zero */
1513 if (btf_record_has_field(htab->map.record, BPF_TIMER))
1514 bpf_obj_free_timer(htab->map.record,
1515 l->key + round_up(htab->map.key_size, 8));
1516 if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
1517 bpf_obj_free_workqueue(htab->map.record,
1518 l->key + round_up(htab->map.key_size, 8));
1519 }
1520 cond_resched_rcu();
1521 }
1522 rcu_read_unlock();
1523 }
1524
htab_map_free_timers_and_wq(struct bpf_map * map)1525 static void htab_map_free_timers_and_wq(struct bpf_map *map)
1526 {
1527 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1528
1529 /* We only free timer and workqueue on uref dropping to zero */
1530 if (btf_record_has_field(htab->map.record, BPF_TIMER | BPF_WORKQUEUE)) {
1531 if (!htab_is_prealloc(htab))
1532 htab_free_malloced_timers_and_wq(htab);
1533 else
1534 htab_free_prealloced_timers_and_wq(htab);
1535 }
1536 }
1537
1538 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
htab_map_free(struct bpf_map * map)1539 static void htab_map_free(struct bpf_map *map)
1540 {
1541 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1542 int i;
1543
1544 /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
1545 * bpf_free_used_maps() is called after bpf prog is no longer executing.
1546 * There is no need to synchronize_rcu() here to protect map elements.
1547 */
1548
1549 /* htab no longer uses call_rcu() directly. bpf_mem_alloc does it
1550 * underneath and is responsible for waiting for callbacks to finish
1551 * during bpf_mem_alloc_destroy().
1552 */
1553 if (!htab_is_prealloc(htab)) {
1554 delete_all_elements(htab);
1555 } else {
1556 htab_free_prealloced_fields(htab);
1557 prealloc_destroy(htab);
1558 }
1559
1560 bpf_map_free_elem_count(map);
1561 free_percpu(htab->extra_elems);
1562 bpf_map_area_free(htab->buckets);
1563 bpf_mem_alloc_destroy(&htab->pcpu_ma);
1564 bpf_mem_alloc_destroy(&htab->ma);
1565 if (htab->use_percpu_counter)
1566 percpu_counter_destroy(&htab->pcount);
1567 for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
1568 free_percpu(htab->map_locked[i]);
1569 lockdep_unregister_key(&htab->lockdep_key);
1570 bpf_map_area_free(htab);
1571 }
1572
htab_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)1573 static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1574 struct seq_file *m)
1575 {
1576 void *value;
1577
1578 rcu_read_lock();
1579
1580 value = htab_map_lookup_elem(map, key);
1581 if (!value) {
1582 rcu_read_unlock();
1583 return;
1584 }
1585
1586 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1587 seq_puts(m, ": ");
1588 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1589 seq_puts(m, "\n");
1590
1591 rcu_read_unlock();
1592 }
1593
__htab_map_lookup_and_delete_elem(struct bpf_map * map,void * key,void * value,bool is_lru_map,bool is_percpu,u64 flags)1594 static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1595 void *value, bool is_lru_map,
1596 bool is_percpu, u64 flags)
1597 {
1598 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1599 struct hlist_nulls_head *head;
1600 unsigned long bflags;
1601 struct htab_elem *l;
1602 u32 hash, key_size;
1603 struct bucket *b;
1604 int ret;
1605
1606 key_size = map->key_size;
1607
1608 hash = htab_map_hash(key, key_size, htab->hashrnd);
1609 b = __select_bucket(htab, hash);
1610 head = &b->head;
1611
1612 ret = htab_lock_bucket(htab, b, hash, &bflags);
1613 if (ret)
1614 return ret;
1615
1616 l = lookup_elem_raw(head, hash, key, key_size);
1617 if (!l) {
1618 ret = -ENOENT;
1619 } else {
1620 if (is_percpu) {
1621 u32 roundup_value_size = round_up(map->value_size, 8);
1622 void __percpu *pptr;
1623 int off = 0, cpu;
1624
1625 pptr = htab_elem_get_ptr(l, key_size);
1626 for_each_possible_cpu(cpu) {
1627 copy_map_value_long(&htab->map, value + off, per_cpu_ptr(pptr, cpu));
1628 check_and_init_map_value(&htab->map, value + off);
1629 off += roundup_value_size;
1630 }
1631 } else {
1632 u32 roundup_key_size = round_up(map->key_size, 8);
1633
1634 if (flags & BPF_F_LOCK)
1635 copy_map_value_locked(map, value, l->key +
1636 roundup_key_size,
1637 true);
1638 else
1639 copy_map_value(map, value, l->key +
1640 roundup_key_size);
1641 /* Zeroing special fields in the temp buffer */
1642 check_and_init_map_value(map, value);
1643 }
1644
1645 hlist_nulls_del_rcu(&l->hash_node);
1646 if (!is_lru_map)
1647 free_htab_elem(htab, l);
1648 }
1649
1650 htab_unlock_bucket(htab, b, hash, bflags);
1651
1652 if (is_lru_map && l)
1653 htab_lru_push_free(htab, l);
1654
1655 return ret;
1656 }
1657
htab_map_lookup_and_delete_elem(struct bpf_map * map,void * key,void * value,u64 flags)1658 static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1659 void *value, u64 flags)
1660 {
1661 return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
1662 flags);
1663 }
1664
htab_percpu_map_lookup_and_delete_elem(struct bpf_map * map,void * key,void * value,u64 flags)1665 static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1666 void *key, void *value,
1667 u64 flags)
1668 {
1669 return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
1670 flags);
1671 }
1672
htab_lru_map_lookup_and_delete_elem(struct bpf_map * map,void * key,void * value,u64 flags)1673 static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1674 void *value, u64 flags)
1675 {
1676 return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
1677 flags);
1678 }
1679
htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map * map,void * key,void * value,u64 flags)1680 static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1681 void *key, void *value,
1682 u64 flags)
1683 {
1684 return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
1685 flags);
1686 }
1687
1688 static int
__htab_map_lookup_and_delete_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr,bool do_delete,bool is_lru_map,bool is_percpu)1689 __htab_map_lookup_and_delete_batch(struct bpf_map *map,
1690 const union bpf_attr *attr,
1691 union bpf_attr __user *uattr,
1692 bool do_delete, bool is_lru_map,
1693 bool is_percpu)
1694 {
1695 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1696 u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
1697 void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
1698 void __user *uvalues = u64_to_user_ptr(attr->batch.values);
1699 void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
1700 void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
1701 u32 batch, max_count, size, bucket_size, map_id;
1702 struct htab_elem *node_to_free = NULL;
1703 u64 elem_map_flags, map_flags;
1704 struct hlist_nulls_head *head;
1705 struct hlist_nulls_node *n;
1706 unsigned long flags = 0;
1707 bool locked = false;
1708 struct htab_elem *l;
1709 struct bucket *b;
1710 int ret = 0;
1711
1712 elem_map_flags = attr->batch.elem_flags;
1713 if ((elem_map_flags & ~BPF_F_LOCK) ||
1714 ((elem_map_flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
1715 return -EINVAL;
1716
1717 map_flags = attr->batch.flags;
1718 if (map_flags)
1719 return -EINVAL;
1720
1721 max_count = attr->batch.count;
1722 if (!max_count)
1723 return 0;
1724
1725 if (put_user(0, &uattr->batch.count))
1726 return -EFAULT;
1727
1728 batch = 0;
1729 if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1730 return -EFAULT;
1731
1732 if (batch >= htab->n_buckets)
1733 return -ENOENT;
1734
1735 key_size = htab->map.key_size;
1736 roundup_key_size = round_up(htab->map.key_size, 8);
1737 value_size = htab->map.value_size;
1738 size = round_up(value_size, 8);
1739 if (is_percpu)
1740 value_size = size * num_possible_cpus();
1741 total = 0;
1742 /* while experimenting with hash tables with sizes ranging from 10 to
1743 * 1000, it was observed that a bucket can have up to 5 entries.
1744 */
1745 bucket_size = 5;
1746
1747 alloc:
1748 /* We cannot do copy_from_user or copy_to_user inside
1749 * the rcu_read_lock. Allocate enough space here.
1750 */
1751 keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
1752 values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
1753 if (!keys || !values) {
1754 ret = -ENOMEM;
1755 goto after_loop;
1756 }
1757
1758 again:
1759 bpf_disable_instrumentation();
1760 rcu_read_lock();
1761 again_nocopy:
1762 dst_key = keys;
1763 dst_val = values;
1764 b = &htab->buckets[batch];
1765 head = &b->head;
1766 /* do not grab the lock unless need it (bucket_cnt > 0). */
1767 if (locked) {
1768 ret = htab_lock_bucket(htab, b, batch, &flags);
1769 if (ret) {
1770 rcu_read_unlock();
1771 bpf_enable_instrumentation();
1772 goto after_loop;
1773 }
1774 }
1775
1776 bucket_cnt = 0;
1777 hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1778 bucket_cnt++;
1779
1780 if (bucket_cnt && !locked) {
1781 locked = true;
1782 goto again_nocopy;
1783 }
1784
1785 if (bucket_cnt > (max_count - total)) {
1786 if (total == 0)
1787 ret = -ENOSPC;
1788 /* Note that since bucket_cnt > 0 here, it is implicit
1789 * that the locked was grabbed, so release it.
1790 */
1791 htab_unlock_bucket(htab, b, batch, flags);
1792 rcu_read_unlock();
1793 bpf_enable_instrumentation();
1794 goto after_loop;
1795 }
1796
1797 if (bucket_cnt > bucket_size) {
1798 bucket_size = bucket_cnt;
1799 /* Note that since bucket_cnt > 0 here, it is implicit
1800 * that the locked was grabbed, so release it.
1801 */
1802 htab_unlock_bucket(htab, b, batch, flags);
1803 rcu_read_unlock();
1804 bpf_enable_instrumentation();
1805 kvfree(keys);
1806 kvfree(values);
1807 goto alloc;
1808 }
1809
1810 /* Next block is only safe to run if you have grabbed the lock */
1811 if (!locked)
1812 goto next_batch;
1813
1814 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1815 memcpy(dst_key, l->key, key_size);
1816
1817 if (is_percpu) {
1818 int off = 0, cpu;
1819 void __percpu *pptr;
1820
1821 pptr = htab_elem_get_ptr(l, map->key_size);
1822 for_each_possible_cpu(cpu) {
1823 copy_map_value_long(&htab->map, dst_val + off, per_cpu_ptr(pptr, cpu));
1824 check_and_init_map_value(&htab->map, dst_val + off);
1825 off += size;
1826 }
1827 } else {
1828 value = l->key + roundup_key_size;
1829 if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
1830 struct bpf_map **inner_map = value;
1831
1832 /* Actual value is the id of the inner map */
1833 map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
1834 value = &map_id;
1835 }
1836
1837 if (elem_map_flags & BPF_F_LOCK)
1838 copy_map_value_locked(map, dst_val, value,
1839 true);
1840 else
1841 copy_map_value(map, dst_val, value);
1842 /* Zeroing special fields in the temp buffer */
1843 check_and_init_map_value(map, dst_val);
1844 }
1845 if (do_delete) {
1846 hlist_nulls_del_rcu(&l->hash_node);
1847
1848 /* bpf_lru_push_free() will acquire lru_lock, which
1849 * may cause deadlock. See comments in function
1850 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
1851 * after releasing the bucket lock.
1852 */
1853 if (is_lru_map) {
1854 l->batch_flink = node_to_free;
1855 node_to_free = l;
1856 } else {
1857 free_htab_elem(htab, l);
1858 }
1859 }
1860 dst_key += key_size;
1861 dst_val += value_size;
1862 }
1863
1864 htab_unlock_bucket(htab, b, batch, flags);
1865 locked = false;
1866
1867 while (node_to_free) {
1868 l = node_to_free;
1869 node_to_free = node_to_free->batch_flink;
1870 htab_lru_push_free(htab, l);
1871 }
1872
1873 next_batch:
1874 /* If we are not copying data, we can go to next bucket and avoid
1875 * unlocking the rcu.
1876 */
1877 if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1878 batch++;
1879 goto again_nocopy;
1880 }
1881
1882 rcu_read_unlock();
1883 bpf_enable_instrumentation();
1884 if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
1885 key_size * bucket_cnt) ||
1886 copy_to_user(uvalues + total * value_size, values,
1887 value_size * bucket_cnt))) {
1888 ret = -EFAULT;
1889 goto after_loop;
1890 }
1891
1892 total += bucket_cnt;
1893 batch++;
1894 if (batch >= htab->n_buckets) {
1895 ret = -ENOENT;
1896 goto after_loop;
1897 }
1898 goto again;
1899
1900 after_loop:
1901 if (ret == -EFAULT)
1902 goto out;
1903
1904 /* copy # of entries and next batch */
1905 ubatch = u64_to_user_ptr(attr->batch.out_batch);
1906 if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
1907 put_user(total, &uattr->batch.count))
1908 ret = -EFAULT;
1909
1910 out:
1911 kvfree(keys);
1912 kvfree(values);
1913 return ret;
1914 }
1915
1916 static int
htab_percpu_map_lookup_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1917 htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1918 union bpf_attr __user *uattr)
1919 {
1920 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1921 false, true);
1922 }
1923
1924 static int
htab_percpu_map_lookup_and_delete_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1925 htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1926 const union bpf_attr *attr,
1927 union bpf_attr __user *uattr)
1928 {
1929 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1930 false, true);
1931 }
1932
1933 static int
htab_map_lookup_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1934 htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1935 union bpf_attr __user *uattr)
1936 {
1937 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1938 false, false);
1939 }
1940
1941 static int
htab_map_lookup_and_delete_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1942 htab_map_lookup_and_delete_batch(struct bpf_map *map,
1943 const union bpf_attr *attr,
1944 union bpf_attr __user *uattr)
1945 {
1946 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1947 false, false);
1948 }
1949
1950 static int
htab_lru_percpu_map_lookup_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1951 htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1952 const union bpf_attr *attr,
1953 union bpf_attr __user *uattr)
1954 {
1955 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1956 true, true);
1957 }
1958
1959 static int
htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1960 htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1961 const union bpf_attr *attr,
1962 union bpf_attr __user *uattr)
1963 {
1964 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1965 true, true);
1966 }
1967
1968 static int
htab_lru_map_lookup_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1969 htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1970 union bpf_attr __user *uattr)
1971 {
1972 return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1973 true, false);
1974 }
1975
1976 static int
htab_lru_map_lookup_and_delete_batch(struct bpf_map * map,const union bpf_attr * attr,union bpf_attr __user * uattr)1977 htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1978 const union bpf_attr *attr,
1979 union bpf_attr __user *uattr)
1980 {
1981 return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1982 true, false);
1983 }
1984
1985 struct bpf_iter_seq_hash_map_info {
1986 struct bpf_map *map;
1987 struct bpf_htab *htab;
1988 void *percpu_value_buf; // non-zero means percpu hash
1989 u32 bucket_id;
1990 u32 skip_elems;
1991 };
1992
1993 static struct htab_elem *
bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info * info,struct htab_elem * prev_elem)1994 bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1995 struct htab_elem *prev_elem)
1996 {
1997 const struct bpf_htab *htab = info->htab;
1998 u32 skip_elems = info->skip_elems;
1999 u32 bucket_id = info->bucket_id;
2000 struct hlist_nulls_head *head;
2001 struct hlist_nulls_node *n;
2002 struct htab_elem *elem;
2003 struct bucket *b;
2004 u32 i, count;
2005
2006 if (bucket_id >= htab->n_buckets)
2007 return NULL;
2008
2009 /* try to find next elem in the same bucket */
2010 if (prev_elem) {
2011 /* no update/deletion on this bucket, prev_elem should be still valid
2012 * and we won't skip elements.
2013 */
2014 n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
2015 elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
2016 if (elem)
2017 return elem;
2018
2019 /* not found, unlock and go to the next bucket */
2020 b = &htab->buckets[bucket_id++];
2021 rcu_read_unlock();
2022 skip_elems = 0;
2023 }
2024
2025 for (i = bucket_id; i < htab->n_buckets; i++) {
2026 b = &htab->buckets[i];
2027 rcu_read_lock();
2028
2029 count = 0;
2030 head = &b->head;
2031 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
2032 if (count >= skip_elems) {
2033 info->bucket_id = i;
2034 info->skip_elems = count;
2035 return elem;
2036 }
2037 count++;
2038 }
2039
2040 rcu_read_unlock();
2041 skip_elems = 0;
2042 }
2043
2044 info->bucket_id = i;
2045 info->skip_elems = 0;
2046 return NULL;
2047 }
2048
bpf_hash_map_seq_start(struct seq_file * seq,loff_t * pos)2049 static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
2050 {
2051 struct bpf_iter_seq_hash_map_info *info = seq->private;
2052 struct htab_elem *elem;
2053
2054 elem = bpf_hash_map_seq_find_next(info, NULL);
2055 if (!elem)
2056 return NULL;
2057
2058 if (*pos == 0)
2059 ++*pos;
2060 return elem;
2061 }
2062
bpf_hash_map_seq_next(struct seq_file * seq,void * v,loff_t * pos)2063 static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2064 {
2065 struct bpf_iter_seq_hash_map_info *info = seq->private;
2066
2067 ++*pos;
2068 ++info->skip_elems;
2069 return bpf_hash_map_seq_find_next(info, v);
2070 }
2071
__bpf_hash_map_seq_show(struct seq_file * seq,struct htab_elem * elem)2072 static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
2073 {
2074 struct bpf_iter_seq_hash_map_info *info = seq->private;
2075 u32 roundup_key_size, roundup_value_size;
2076 struct bpf_iter__bpf_map_elem ctx = {};
2077 struct bpf_map *map = info->map;
2078 struct bpf_iter_meta meta;
2079 int ret = 0, off = 0, cpu;
2080 struct bpf_prog *prog;
2081 void __percpu *pptr;
2082
2083 meta.seq = seq;
2084 prog = bpf_iter_get_info(&meta, elem == NULL);
2085 if (prog) {
2086 ctx.meta = &meta;
2087 ctx.map = info->map;
2088 if (elem) {
2089 roundup_key_size = round_up(map->key_size, 8);
2090 ctx.key = elem->key;
2091 if (!info->percpu_value_buf) {
2092 ctx.value = elem->key + roundup_key_size;
2093 } else {
2094 roundup_value_size = round_up(map->value_size, 8);
2095 pptr = htab_elem_get_ptr(elem, map->key_size);
2096 for_each_possible_cpu(cpu) {
2097 copy_map_value_long(map, info->percpu_value_buf + off,
2098 per_cpu_ptr(pptr, cpu));
2099 check_and_init_map_value(map, info->percpu_value_buf + off);
2100 off += roundup_value_size;
2101 }
2102 ctx.value = info->percpu_value_buf;
2103 }
2104 }
2105 ret = bpf_iter_run_prog(prog, &ctx);
2106 }
2107
2108 return ret;
2109 }
2110
bpf_hash_map_seq_show(struct seq_file * seq,void * v)2111 static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
2112 {
2113 return __bpf_hash_map_seq_show(seq, v);
2114 }
2115
bpf_hash_map_seq_stop(struct seq_file * seq,void * v)2116 static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
2117 {
2118 if (!v)
2119 (void)__bpf_hash_map_seq_show(seq, NULL);
2120 else
2121 rcu_read_unlock();
2122 }
2123
bpf_iter_init_hash_map(void * priv_data,struct bpf_iter_aux_info * aux)2124 static int bpf_iter_init_hash_map(void *priv_data,
2125 struct bpf_iter_aux_info *aux)
2126 {
2127 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
2128 struct bpf_map *map = aux->map;
2129 void *value_buf;
2130 u32 buf_size;
2131
2132 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
2133 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
2134 buf_size = round_up(map->value_size, 8) * num_possible_cpus();
2135 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
2136 if (!value_buf)
2137 return -ENOMEM;
2138
2139 seq_info->percpu_value_buf = value_buf;
2140 }
2141
2142 bpf_map_inc_with_uref(map);
2143 seq_info->map = map;
2144 seq_info->htab = container_of(map, struct bpf_htab, map);
2145 return 0;
2146 }
2147
bpf_iter_fini_hash_map(void * priv_data)2148 static void bpf_iter_fini_hash_map(void *priv_data)
2149 {
2150 struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
2151
2152 bpf_map_put_with_uref(seq_info->map);
2153 kfree(seq_info->percpu_value_buf);
2154 }
2155
2156 static const struct seq_operations bpf_hash_map_seq_ops = {
2157 .start = bpf_hash_map_seq_start,
2158 .next = bpf_hash_map_seq_next,
2159 .stop = bpf_hash_map_seq_stop,
2160 .show = bpf_hash_map_seq_show,
2161 };
2162
2163 static const struct bpf_iter_seq_info iter_seq_info = {
2164 .seq_ops = &bpf_hash_map_seq_ops,
2165 .init_seq_private = bpf_iter_init_hash_map,
2166 .fini_seq_private = bpf_iter_fini_hash_map,
2167 .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
2168 };
2169
bpf_for_each_hash_elem(struct bpf_map * map,bpf_callback_t callback_fn,void * callback_ctx,u64 flags)2170 static long bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn,
2171 void *callback_ctx, u64 flags)
2172 {
2173 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2174 struct hlist_nulls_head *head;
2175 struct hlist_nulls_node *n;
2176 struct htab_elem *elem;
2177 u32 roundup_key_size;
2178 int i, num_elems = 0;
2179 void __percpu *pptr;
2180 struct bucket *b;
2181 void *key, *val;
2182 bool is_percpu;
2183 u64 ret = 0;
2184
2185 if (flags != 0)
2186 return -EINVAL;
2187
2188 is_percpu = htab_is_percpu(htab);
2189
2190 roundup_key_size = round_up(map->key_size, 8);
2191 /* disable migration so percpu value prepared here will be the
2192 * same as the one seen by the bpf program with bpf_map_lookup_elem().
2193 */
2194 if (is_percpu)
2195 migrate_disable();
2196 for (i = 0; i < htab->n_buckets; i++) {
2197 b = &htab->buckets[i];
2198 rcu_read_lock();
2199 head = &b->head;
2200 hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
2201 key = elem->key;
2202 if (is_percpu) {
2203 /* current cpu value for percpu map */
2204 pptr = htab_elem_get_ptr(elem, map->key_size);
2205 val = this_cpu_ptr(pptr);
2206 } else {
2207 val = elem->key + roundup_key_size;
2208 }
2209 num_elems++;
2210 ret = callback_fn((u64)(long)map, (u64)(long)key,
2211 (u64)(long)val, (u64)(long)callback_ctx, 0);
2212 /* return value: 0 - continue, 1 - stop and return */
2213 if (ret) {
2214 rcu_read_unlock();
2215 goto out;
2216 }
2217 }
2218 rcu_read_unlock();
2219 }
2220 out:
2221 if (is_percpu)
2222 migrate_enable();
2223 return num_elems;
2224 }
2225
htab_map_mem_usage(const struct bpf_map * map)2226 static u64 htab_map_mem_usage(const struct bpf_map *map)
2227 {
2228 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2229 u32 value_size = round_up(htab->map.value_size, 8);
2230 bool prealloc = htab_is_prealloc(htab);
2231 bool percpu = htab_is_percpu(htab);
2232 bool lru = htab_is_lru(htab);
2233 u64 num_entries;
2234 u64 usage = sizeof(struct bpf_htab);
2235
2236 usage += sizeof(struct bucket) * htab->n_buckets;
2237 usage += sizeof(int) * num_possible_cpus() * HASHTAB_MAP_LOCK_COUNT;
2238 if (prealloc) {
2239 num_entries = map->max_entries;
2240 if (htab_has_extra_elems(htab))
2241 num_entries += num_possible_cpus();
2242
2243 usage += htab->elem_size * num_entries;
2244
2245 if (percpu)
2246 usage += value_size * num_possible_cpus() * num_entries;
2247 else if (!lru)
2248 usage += sizeof(struct htab_elem *) * num_possible_cpus();
2249 } else {
2250 #define LLIST_NODE_SZ sizeof(struct llist_node)
2251
2252 num_entries = htab->use_percpu_counter ?
2253 percpu_counter_sum(&htab->pcount) :
2254 atomic_read(&htab->count);
2255 usage += (htab->elem_size + LLIST_NODE_SZ) * num_entries;
2256 if (percpu) {
2257 usage += (LLIST_NODE_SZ + sizeof(void *)) * num_entries;
2258 usage += value_size * num_possible_cpus() * num_entries;
2259 }
2260 }
2261 return usage;
2262 }
2263
2264 BTF_ID_LIST_SINGLE(htab_map_btf_ids, struct, bpf_htab)
2265 const struct bpf_map_ops htab_map_ops = {
2266 .map_meta_equal = bpf_map_meta_equal,
2267 .map_alloc_check = htab_map_alloc_check,
2268 .map_alloc = htab_map_alloc,
2269 .map_free = htab_map_free,
2270 .map_get_next_key = htab_map_get_next_key,
2271 .map_release_uref = htab_map_free_timers_and_wq,
2272 .map_lookup_elem = htab_map_lookup_elem,
2273 .map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
2274 .map_update_elem = htab_map_update_elem,
2275 .map_delete_elem = htab_map_delete_elem,
2276 .map_gen_lookup = htab_map_gen_lookup,
2277 .map_seq_show_elem = htab_map_seq_show_elem,
2278 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2279 .map_for_each_callback = bpf_for_each_hash_elem,
2280 .map_mem_usage = htab_map_mem_usage,
2281 BATCH_OPS(htab),
2282 .map_btf_id = &htab_map_btf_ids[0],
2283 .iter_seq_info = &iter_seq_info,
2284 };
2285
2286 const struct bpf_map_ops htab_lru_map_ops = {
2287 .map_meta_equal = bpf_map_meta_equal,
2288 .map_alloc_check = htab_map_alloc_check,
2289 .map_alloc = htab_map_alloc,
2290 .map_free = htab_map_free,
2291 .map_get_next_key = htab_map_get_next_key,
2292 .map_release_uref = htab_map_free_timers_and_wq,
2293 .map_lookup_elem = htab_lru_map_lookup_elem,
2294 .map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
2295 .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
2296 .map_update_elem = htab_lru_map_update_elem,
2297 .map_delete_elem = htab_lru_map_delete_elem,
2298 .map_gen_lookup = htab_lru_map_gen_lookup,
2299 .map_seq_show_elem = htab_map_seq_show_elem,
2300 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2301 .map_for_each_callback = bpf_for_each_hash_elem,
2302 .map_mem_usage = htab_map_mem_usage,
2303 BATCH_OPS(htab_lru),
2304 .map_btf_id = &htab_map_btf_ids[0],
2305 .iter_seq_info = &iter_seq_info,
2306 };
2307
2308 /* Called from eBPF program */
htab_percpu_map_lookup_elem(struct bpf_map * map,void * key)2309 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2310 {
2311 struct htab_elem *l = __htab_map_lookup_elem(map, key);
2312
2313 if (l)
2314 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2315 else
2316 return NULL;
2317 }
2318
2319 /* inline bpf_map_lookup_elem() call for per-CPU hashmap */
htab_percpu_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)2320 static int htab_percpu_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
2321 {
2322 struct bpf_insn *insn = insn_buf;
2323
2324 if (!bpf_jit_supports_percpu_insn())
2325 return -EOPNOTSUPP;
2326
2327 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2328 (void *(*)(struct bpf_map *map, void *key))NULL));
2329 *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
2330 *insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3);
2331 *insn++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_0,
2332 offsetof(struct htab_elem, key) + map->key_size);
2333 *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0);
2334 *insn++ = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
2335
2336 return insn - insn_buf;
2337 }
2338
htab_percpu_map_lookup_percpu_elem(struct bpf_map * map,void * key,u32 cpu)2339 static void *htab_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
2340 {
2341 struct htab_elem *l;
2342
2343 if (cpu >= nr_cpu_ids)
2344 return NULL;
2345
2346 l = __htab_map_lookup_elem(map, key);
2347 if (l)
2348 return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
2349 else
2350 return NULL;
2351 }
2352
htab_lru_percpu_map_lookup_elem(struct bpf_map * map,void * key)2353 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2354 {
2355 struct htab_elem *l = __htab_map_lookup_elem(map, key);
2356
2357 if (l) {
2358 bpf_lru_node_set_ref(&l->lru_node);
2359 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2360 }
2361
2362 return NULL;
2363 }
2364
htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map * map,void * key,u32 cpu)2365 static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
2366 {
2367 struct htab_elem *l;
2368
2369 if (cpu >= nr_cpu_ids)
2370 return NULL;
2371
2372 l = __htab_map_lookup_elem(map, key);
2373 if (l) {
2374 bpf_lru_node_set_ref(&l->lru_node);
2375 return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
2376 }
2377
2378 return NULL;
2379 }
2380
bpf_percpu_hash_copy(struct bpf_map * map,void * key,void * value)2381 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
2382 {
2383 struct htab_elem *l;
2384 void __percpu *pptr;
2385 int ret = -ENOENT;
2386 int cpu, off = 0;
2387 u32 size;
2388
2389 /* per_cpu areas are zero-filled and bpf programs can only
2390 * access 'value_size' of them, so copying rounded areas
2391 * will not leak any kernel data
2392 */
2393 size = round_up(map->value_size, 8);
2394 rcu_read_lock();
2395 l = __htab_map_lookup_elem(map, key);
2396 if (!l)
2397 goto out;
2398 /* We do not mark LRU map element here in order to not mess up
2399 * eviction heuristics when user space does a map walk.
2400 */
2401 pptr = htab_elem_get_ptr(l, map->key_size);
2402 for_each_possible_cpu(cpu) {
2403 copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
2404 check_and_init_map_value(map, value + off);
2405 off += size;
2406 }
2407 ret = 0;
2408 out:
2409 rcu_read_unlock();
2410 return ret;
2411 }
2412
bpf_percpu_hash_update(struct bpf_map * map,void * key,void * value,u64 map_flags)2413 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
2414 u64 map_flags)
2415 {
2416 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2417 int ret;
2418
2419 rcu_read_lock();
2420 if (htab_is_lru(htab))
2421 ret = __htab_lru_percpu_map_update_elem(map, key, value,
2422 map_flags, true);
2423 else
2424 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
2425 true);
2426 rcu_read_unlock();
2427
2428 return ret;
2429 }
2430
htab_percpu_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)2431 static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
2432 struct seq_file *m)
2433 {
2434 struct htab_elem *l;
2435 void __percpu *pptr;
2436 int cpu;
2437
2438 rcu_read_lock();
2439
2440 l = __htab_map_lookup_elem(map, key);
2441 if (!l) {
2442 rcu_read_unlock();
2443 return;
2444 }
2445
2446 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
2447 seq_puts(m, ": {\n");
2448 pptr = htab_elem_get_ptr(l, map->key_size);
2449 for_each_possible_cpu(cpu) {
2450 seq_printf(m, "\tcpu%d: ", cpu);
2451 btf_type_seq_show(map->btf, map->btf_value_type_id,
2452 per_cpu_ptr(pptr, cpu), m);
2453 seq_puts(m, "\n");
2454 }
2455 seq_puts(m, "}\n");
2456
2457 rcu_read_unlock();
2458 }
2459
2460 const struct bpf_map_ops htab_percpu_map_ops = {
2461 .map_meta_equal = bpf_map_meta_equal,
2462 .map_alloc_check = htab_map_alloc_check,
2463 .map_alloc = htab_map_alloc,
2464 .map_free = htab_map_free,
2465 .map_get_next_key = htab_map_get_next_key,
2466 .map_lookup_elem = htab_percpu_map_lookup_elem,
2467 .map_gen_lookup = htab_percpu_map_gen_lookup,
2468 .map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
2469 .map_update_elem = htab_percpu_map_update_elem,
2470 .map_delete_elem = htab_map_delete_elem,
2471 .map_lookup_percpu_elem = htab_percpu_map_lookup_percpu_elem,
2472 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2473 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2474 .map_for_each_callback = bpf_for_each_hash_elem,
2475 .map_mem_usage = htab_map_mem_usage,
2476 BATCH_OPS(htab_percpu),
2477 .map_btf_id = &htab_map_btf_ids[0],
2478 .iter_seq_info = &iter_seq_info,
2479 };
2480
2481 const struct bpf_map_ops htab_lru_percpu_map_ops = {
2482 .map_meta_equal = bpf_map_meta_equal,
2483 .map_alloc_check = htab_map_alloc_check,
2484 .map_alloc = htab_map_alloc,
2485 .map_free = htab_map_free,
2486 .map_get_next_key = htab_map_get_next_key,
2487 .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
2488 .map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
2489 .map_update_elem = htab_lru_percpu_map_update_elem,
2490 .map_delete_elem = htab_lru_map_delete_elem,
2491 .map_lookup_percpu_elem = htab_lru_percpu_map_lookup_percpu_elem,
2492 .map_seq_show_elem = htab_percpu_map_seq_show_elem,
2493 .map_set_for_each_callback_args = map_set_for_each_callback_args,
2494 .map_for_each_callback = bpf_for_each_hash_elem,
2495 .map_mem_usage = htab_map_mem_usage,
2496 BATCH_OPS(htab_lru_percpu),
2497 .map_btf_id = &htab_map_btf_ids[0],
2498 .iter_seq_info = &iter_seq_info,
2499 };
2500
fd_htab_map_alloc_check(union bpf_attr * attr)2501 static int fd_htab_map_alloc_check(union bpf_attr *attr)
2502 {
2503 if (attr->value_size != sizeof(u32))
2504 return -EINVAL;
2505 return htab_map_alloc_check(attr);
2506 }
2507
fd_htab_map_free(struct bpf_map * map)2508 static void fd_htab_map_free(struct bpf_map *map)
2509 {
2510 struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2511 struct hlist_nulls_node *n;
2512 struct hlist_nulls_head *head;
2513 struct htab_elem *l;
2514 int i;
2515
2516 for (i = 0; i < htab->n_buckets; i++) {
2517 head = select_bucket(htab, i);
2518
2519 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
2520 void *ptr = fd_htab_map_get_ptr(map, l);
2521
2522 map->ops->map_fd_put_ptr(map, ptr, false);
2523 }
2524 }
2525
2526 htab_map_free(map);
2527 }
2528
2529 /* only called from syscall */
bpf_fd_htab_map_lookup_elem(struct bpf_map * map,void * key,u32 * value)2530 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2531 {
2532 void **ptr;
2533 int ret = 0;
2534
2535 if (!map->ops->map_fd_sys_lookup_elem)
2536 return -ENOTSUPP;
2537
2538 rcu_read_lock();
2539 ptr = htab_map_lookup_elem(map, key);
2540 if (ptr)
2541 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2542 else
2543 ret = -ENOENT;
2544 rcu_read_unlock();
2545
2546 return ret;
2547 }
2548
2549 /* only called from syscall */
bpf_fd_htab_map_update_elem(struct bpf_map * map,struct file * map_file,void * key,void * value,u64 map_flags)2550 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2551 void *key, void *value, u64 map_flags)
2552 {
2553 void *ptr;
2554 int ret;
2555 u32 ufd = *(u32 *)value;
2556
2557 ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2558 if (IS_ERR(ptr))
2559 return PTR_ERR(ptr);
2560
2561 /* The htab bucket lock is always held during update operations in fd
2562 * htab map, and the following rcu_read_lock() is only used to avoid
2563 * the WARN_ON_ONCE in htab_map_update_elem().
2564 */
2565 rcu_read_lock();
2566 ret = htab_map_update_elem(map, key, &ptr, map_flags);
2567 rcu_read_unlock();
2568 if (ret)
2569 map->ops->map_fd_put_ptr(map, ptr, false);
2570
2571 return ret;
2572 }
2573
htab_of_map_alloc(union bpf_attr * attr)2574 static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2575 {
2576 struct bpf_map *map, *inner_map_meta;
2577
2578 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2579 if (IS_ERR(inner_map_meta))
2580 return inner_map_meta;
2581
2582 map = htab_map_alloc(attr);
2583 if (IS_ERR(map)) {
2584 bpf_map_meta_free(inner_map_meta);
2585 return map;
2586 }
2587
2588 map->inner_map_meta = inner_map_meta;
2589
2590 return map;
2591 }
2592
htab_of_map_lookup_elem(struct bpf_map * map,void * key)2593 static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2594 {
2595 struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
2596
2597 if (!inner_map)
2598 return NULL;
2599
2600 return READ_ONCE(*inner_map);
2601 }
2602
htab_of_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)2603 static int htab_of_map_gen_lookup(struct bpf_map *map,
2604 struct bpf_insn *insn_buf)
2605 {
2606 struct bpf_insn *insn = insn_buf;
2607 const int ret = BPF_REG_0;
2608
2609 BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2610 (void *(*)(struct bpf_map *map, void *key))NULL));
2611 *insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
2612 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2613 *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2614 offsetof(struct htab_elem, key) +
2615 round_up(map->key_size, 8));
2616 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2617
2618 return insn - insn_buf;
2619 }
2620
htab_of_map_free(struct bpf_map * map)2621 static void htab_of_map_free(struct bpf_map *map)
2622 {
2623 bpf_map_meta_free(map->inner_map_meta);
2624 fd_htab_map_free(map);
2625 }
2626
2627 const struct bpf_map_ops htab_of_maps_map_ops = {
2628 .map_alloc_check = fd_htab_map_alloc_check,
2629 .map_alloc = htab_of_map_alloc,
2630 .map_free = htab_of_map_free,
2631 .map_get_next_key = htab_map_get_next_key,
2632 .map_lookup_elem = htab_of_map_lookup_elem,
2633 .map_delete_elem = htab_map_delete_elem,
2634 .map_fd_get_ptr = bpf_map_fd_get_ptr,
2635 .map_fd_put_ptr = bpf_map_fd_put_ptr,
2636 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2637 .map_gen_lookup = htab_of_map_gen_lookup,
2638 .map_check_btf = map_check_no_btf,
2639 .map_mem_usage = htab_map_mem_usage,
2640 BATCH_OPS(htab),
2641 .map_btf_id = &htab_map_btf_ids[0],
2642 };
2643