Commit | Line | Data |
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0f8e4bd8 | 1 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
6c905981 | 2 | * Copyright (c) 2016 Facebook |
0f8e4bd8 AS |
3 | * |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of version 2 of the GNU General Public | |
6 | * License as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | */ | |
13 | #include <linux/bpf.h> | |
14 | #include <linux/jhash.h> | |
15 | #include <linux/filter.h> | |
16 | #include <linux/vmalloc.h> | |
6c905981 | 17 | #include "percpu_freelist.h" |
0f8e4bd8 | 18 | |
688ecfe6 | 19 | struct bucket { |
20 | struct hlist_head head; | |
21 | raw_spinlock_t lock; | |
22 | }; | |
23 | ||
0f8e4bd8 AS |
24 | struct bpf_htab { |
25 | struct bpf_map map; | |
688ecfe6 | 26 | struct bucket *buckets; |
6c905981 AS |
27 | void *elems; |
28 | struct pcpu_freelist freelist; | |
6591f1e6 | 29 | atomic_t count; /* number of elements in this hashtable */ |
0f8e4bd8 AS |
30 | u32 n_buckets; /* number of hash buckets */ |
31 | u32 elem_size; /* size of each element in bytes */ | |
32 | }; | |
33 | ||
34 | /* each htab element is struct htab_elem + key + value */ | |
35 | struct htab_elem { | |
824bd0ce | 36 | union { |
6c905981 AS |
37 | struct hlist_node hash_node; |
38 | struct bpf_htab *htab; | |
39 | struct pcpu_freelist_node fnode; | |
824bd0ce | 40 | }; |
6c905981 AS |
41 | struct rcu_head rcu; |
42 | u32 hash; | |
0f8e4bd8 AS |
43 | char key[0] __aligned(8); |
44 | }; | |
45 | ||
6c905981 AS |
46 | static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size, |
47 | void __percpu *pptr) | |
48 | { | |
49 | *(void __percpu **)(l->key + key_size) = pptr; | |
50 | } | |
51 | ||
52 | static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size) | |
53 | { | |
54 | return *(void __percpu **)(l->key + key_size); | |
55 | } | |
56 | ||
57 | static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i) | |
58 | { | |
59 | return (struct htab_elem *) (htab->elems + i * htab->elem_size); | |
60 | } | |
61 | ||
62 | static void htab_free_elems(struct bpf_htab *htab) | |
63 | { | |
64 | int i; | |
65 | ||
66 | if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) | |
67 | goto free_elems; | |
68 | ||
69 | for (i = 0; i < htab->map.max_entries; i++) { | |
70 | void __percpu *pptr; | |
71 | ||
72 | pptr = htab_elem_get_ptr(get_htab_elem(htab, i), | |
73 | htab->map.key_size); | |
74 | free_percpu(pptr); | |
75 | } | |
76 | free_elems: | |
77 | vfree(htab->elems); | |
78 | } | |
79 | ||
80 | static int prealloc_elems_and_freelist(struct bpf_htab *htab) | |
81 | { | |
82 | int err = -ENOMEM, i; | |
83 | ||
84 | htab->elems = vzalloc(htab->elem_size * htab->map.max_entries); | |
85 | if (!htab->elems) | |
86 | return -ENOMEM; | |
87 | ||
88 | if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) | |
89 | goto skip_percpu_elems; | |
90 | ||
91 | for (i = 0; i < htab->map.max_entries; i++) { | |
92 | u32 size = round_up(htab->map.value_size, 8); | |
93 | void __percpu *pptr; | |
94 | ||
95 | pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN); | |
96 | if (!pptr) | |
97 | goto free_elems; | |
98 | htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size, | |
99 | pptr); | |
100 | } | |
101 | ||
102 | skip_percpu_elems: | |
103 | err = pcpu_freelist_init(&htab->freelist); | |
104 | if (err) | |
105 | goto free_elems; | |
106 | ||
107 | pcpu_freelist_populate(&htab->freelist, htab->elems, htab->elem_size, | |
108 | htab->map.max_entries); | |
109 | return 0; | |
110 | ||
111 | free_elems: | |
112 | htab_free_elems(htab); | |
113 | return err; | |
114 | } | |
115 | ||
0f8e4bd8 AS |
116 | /* Called from syscall */ |
117 | static struct bpf_map *htab_map_alloc(union bpf_attr *attr) | |
118 | { | |
824bd0ce | 119 | bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_HASH; |
0f8e4bd8 AS |
120 | struct bpf_htab *htab; |
121 | int err, i; | |
824bd0ce | 122 | u64 cost; |
0f8e4bd8 | 123 | |
6c905981 AS |
124 | if (attr->map_flags & ~BPF_F_NO_PREALLOC) |
125 | /* reserved bits should not be used */ | |
126 | return ERR_PTR(-EINVAL); | |
127 | ||
0f8e4bd8 AS |
128 | htab = kzalloc(sizeof(*htab), GFP_USER); |
129 | if (!htab) | |
130 | return ERR_PTR(-ENOMEM); | |
131 | ||
132 | /* mandatory map attributes */ | |
824bd0ce | 133 | htab->map.map_type = attr->map_type; |
0f8e4bd8 AS |
134 | htab->map.key_size = attr->key_size; |
135 | htab->map.value_size = attr->value_size; | |
136 | htab->map.max_entries = attr->max_entries; | |
6c905981 | 137 | htab->map.map_flags = attr->map_flags; |
0f8e4bd8 AS |
138 | |
139 | /* check sanity of attributes. | |
140 | * value_size == 0 may be allowed in the future to use map as a set | |
141 | */ | |
142 | err = -EINVAL; | |
143 | if (htab->map.max_entries == 0 || htab->map.key_size == 0 || | |
144 | htab->map.value_size == 0) | |
145 | goto free_htab; | |
146 | ||
147 | /* hash table size must be power of 2 */ | |
148 | htab->n_buckets = roundup_pow_of_two(htab->map.max_entries); | |
149 | ||
150 | err = -E2BIG; | |
151 | if (htab->map.key_size > MAX_BPF_STACK) | |
152 | /* eBPF programs initialize keys on stack, so they cannot be | |
153 | * larger than max stack size | |
154 | */ | |
155 | goto free_htab; | |
156 | ||
01b3f521 AS |
157 | if (htab->map.value_size >= (1 << (KMALLOC_SHIFT_MAX - 1)) - |
158 | MAX_BPF_STACK - sizeof(struct htab_elem)) | |
159 | /* if value_size is bigger, the user space won't be able to | |
160 | * access the elements via bpf syscall. This check also makes | |
161 | * sure that the elem_size doesn't overflow and it's | |
162 | * kmalloc-able later in htab_map_update_elem() | |
163 | */ | |
164 | goto free_htab; | |
165 | ||
824bd0ce AS |
166 | if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE) |
167 | /* make sure the size for pcpu_alloc() is reasonable */ | |
168 | goto free_htab; | |
169 | ||
01b3f521 | 170 | htab->elem_size = sizeof(struct htab_elem) + |
824bd0ce AS |
171 | round_up(htab->map.key_size, 8); |
172 | if (percpu) | |
173 | htab->elem_size += sizeof(void *); | |
174 | else | |
6c905981 | 175 | htab->elem_size += round_up(htab->map.value_size, 8); |
01b3f521 | 176 | |
daaf427c AS |
177 | /* prevent zero size kmalloc and check for u32 overflow */ |
178 | if (htab->n_buckets == 0 || | |
688ecfe6 | 179 | htab->n_buckets > U32_MAX / sizeof(struct bucket)) |
daaf427c AS |
180 | goto free_htab; |
181 | ||
824bd0ce AS |
182 | cost = (u64) htab->n_buckets * sizeof(struct bucket) + |
183 | (u64) htab->elem_size * htab->map.max_entries; | |
184 | ||
185 | if (percpu) | |
186 | cost += (u64) round_up(htab->map.value_size, 8) * | |
187 | num_possible_cpus() * htab->map.max_entries; | |
188 | ||
189 | if (cost >= U32_MAX - PAGE_SIZE) | |
01b3f521 AS |
190 | /* make sure page count doesn't overflow */ |
191 | goto free_htab; | |
192 | ||
824bd0ce | 193 | htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; |
01b3f521 | 194 | |
6c905981 AS |
195 | /* if map size is larger than memlock limit, reject it early */ |
196 | err = bpf_map_precharge_memlock(htab->map.pages); | |
197 | if (err) | |
198 | goto free_htab; | |
199 | ||
01b3f521 | 200 | err = -ENOMEM; |
688ecfe6 | 201 | htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct bucket), |
0f8e4bd8 AS |
202 | GFP_USER | __GFP_NOWARN); |
203 | ||
204 | if (!htab->buckets) { | |
688ecfe6 | 205 | htab->buckets = vmalloc(htab->n_buckets * sizeof(struct bucket)); |
0f8e4bd8 AS |
206 | if (!htab->buckets) |
207 | goto free_htab; | |
208 | } | |
209 | ||
688ecfe6 | 210 | for (i = 0; i < htab->n_buckets; i++) { |
211 | INIT_HLIST_HEAD(&htab->buckets[i].head); | |
212 | raw_spin_lock_init(&htab->buckets[i].lock); | |
213 | } | |
0f8e4bd8 | 214 | |
6c905981 AS |
215 | if (!(attr->map_flags & BPF_F_NO_PREALLOC)) { |
216 | err = prealloc_elems_and_freelist(htab); | |
217 | if (err) | |
218 | goto free_buckets; | |
219 | } | |
0f8e4bd8 | 220 | |
0f8e4bd8 AS |
221 | return &htab->map; |
222 | ||
6c905981 AS |
223 | free_buckets: |
224 | kvfree(htab->buckets); | |
0f8e4bd8 AS |
225 | free_htab: |
226 | kfree(htab); | |
227 | return ERR_PTR(err); | |
228 | } | |
229 | ||
230 | static inline u32 htab_map_hash(const void *key, u32 key_len) | |
231 | { | |
232 | return jhash(key, key_len, 0); | |
233 | } | |
234 | ||
688ecfe6 | 235 | static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash) |
0f8e4bd8 AS |
236 | { |
237 | return &htab->buckets[hash & (htab->n_buckets - 1)]; | |
238 | } | |
239 | ||
688ecfe6 | 240 | static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash) |
241 | { | |
242 | return &__select_bucket(htab, hash)->head; | |
243 | } | |
244 | ||
0f8e4bd8 AS |
245 | static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash, |
246 | void *key, u32 key_size) | |
247 | { | |
248 | struct htab_elem *l; | |
249 | ||
250 | hlist_for_each_entry_rcu(l, head, hash_node) | |
251 | if (l->hash == hash && !memcmp(&l->key, key, key_size)) | |
252 | return l; | |
253 | ||
254 | return NULL; | |
255 | } | |
256 | ||
257 | /* Called from syscall or from eBPF program */ | |
824bd0ce | 258 | static void *__htab_map_lookup_elem(struct bpf_map *map, void *key) |
0f8e4bd8 AS |
259 | { |
260 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
261 | struct hlist_head *head; | |
262 | struct htab_elem *l; | |
263 | u32 hash, key_size; | |
264 | ||
265 | /* Must be called with rcu_read_lock. */ | |
266 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
267 | ||
268 | key_size = map->key_size; | |
269 | ||
270 | hash = htab_map_hash(key, key_size); | |
271 | ||
272 | head = select_bucket(htab, hash); | |
273 | ||
274 | l = lookup_elem_raw(head, hash, key, key_size); | |
275 | ||
824bd0ce AS |
276 | return l; |
277 | } | |
278 | ||
279 | static void *htab_map_lookup_elem(struct bpf_map *map, void *key) | |
280 | { | |
281 | struct htab_elem *l = __htab_map_lookup_elem(map, key); | |
282 | ||
0f8e4bd8 AS |
283 | if (l) |
284 | return l->key + round_up(map->key_size, 8); | |
285 | ||
286 | return NULL; | |
287 | } | |
288 | ||
289 | /* Called from syscall */ | |
290 | static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key) | |
291 | { | |
292 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
293 | struct hlist_head *head; | |
294 | struct htab_elem *l, *next_l; | |
295 | u32 hash, key_size; | |
296 | int i; | |
297 | ||
298 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
299 | ||
300 | key_size = map->key_size; | |
301 | ||
302 | hash = htab_map_hash(key, key_size); | |
303 | ||
304 | head = select_bucket(htab, hash); | |
305 | ||
306 | /* lookup the key */ | |
307 | l = lookup_elem_raw(head, hash, key, key_size); | |
308 | ||
309 | if (!l) { | |
310 | i = 0; | |
311 | goto find_first_elem; | |
312 | } | |
313 | ||
314 | /* key was found, get next key in the same bucket */ | |
315 | next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)), | |
316 | struct htab_elem, hash_node); | |
317 | ||
318 | if (next_l) { | |
319 | /* if next elem in this hash list is non-zero, just return it */ | |
320 | memcpy(next_key, next_l->key, key_size); | |
321 | return 0; | |
322 | } | |
323 | ||
324 | /* no more elements in this hash list, go to the next bucket */ | |
325 | i = hash & (htab->n_buckets - 1); | |
326 | i++; | |
327 | ||
328 | find_first_elem: | |
329 | /* iterate over buckets */ | |
330 | for (; i < htab->n_buckets; i++) { | |
331 | head = select_bucket(htab, i); | |
332 | ||
333 | /* pick first element in the bucket */ | |
334 | next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)), | |
335 | struct htab_elem, hash_node); | |
336 | if (next_l) { | |
337 | /* if it's not empty, just return it */ | |
338 | memcpy(next_key, next_l->key, key_size); | |
339 | return 0; | |
340 | } | |
341 | } | |
342 | ||
6c905981 | 343 | /* iterated over all buckets and all elements */ |
0f8e4bd8 AS |
344 | return -ENOENT; |
345 | } | |
346 | ||
6c905981 | 347 | static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l) |
824bd0ce | 348 | { |
6c905981 AS |
349 | if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) |
350 | free_percpu(htab_elem_get_ptr(l, htab->map.key_size)); | |
824bd0ce | 351 | kfree(l); |
6c905981 | 352 | |
824bd0ce AS |
353 | } |
354 | ||
6c905981 | 355 | static void htab_elem_free_rcu(struct rcu_head *head) |
824bd0ce AS |
356 | { |
357 | struct htab_elem *l = container_of(head, struct htab_elem, rcu); | |
6c905981 | 358 | struct bpf_htab *htab = l->htab; |
824bd0ce | 359 | |
6c905981 AS |
360 | /* must increment bpf_prog_active to avoid kprobe+bpf triggering while |
361 | * we're calling kfree, otherwise deadlock is possible if kprobes | |
362 | * are placed somewhere inside of slub | |
363 | */ | |
364 | preempt_disable(); | |
365 | __this_cpu_inc(bpf_prog_active); | |
366 | htab_elem_free(htab, l); | |
367 | __this_cpu_dec(bpf_prog_active); | |
368 | preempt_enable(); | |
824bd0ce AS |
369 | } |
370 | ||
6c905981 | 371 | static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) |
824bd0ce | 372 | { |
6c905981 AS |
373 | if (!(htab->map.map_flags & BPF_F_NO_PREALLOC)) { |
374 | pcpu_freelist_push(&htab->freelist, &l->fnode); | |
824bd0ce | 375 | } else { |
6c905981 AS |
376 | atomic_dec(&htab->count); |
377 | l->htab = htab; | |
378 | call_rcu(&l->rcu, htab_elem_free_rcu); | |
824bd0ce AS |
379 | } |
380 | } | |
381 | ||
382 | static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, | |
383 | void *value, u32 key_size, u32 hash, | |
15a07b33 | 384 | bool percpu, bool onallcpus) |
824bd0ce AS |
385 | { |
386 | u32 size = htab->map.value_size; | |
6c905981 | 387 | bool prealloc = !(htab->map.map_flags & BPF_F_NO_PREALLOC); |
824bd0ce AS |
388 | struct htab_elem *l_new; |
389 | void __percpu *pptr; | |
390 | ||
6c905981 AS |
391 | if (prealloc) { |
392 | l_new = (struct htab_elem *)pcpu_freelist_pop(&htab->freelist); | |
393 | if (!l_new) | |
394 | return ERR_PTR(-E2BIG); | |
395 | } else { | |
396 | if (atomic_inc_return(&htab->count) > htab->map.max_entries) { | |
397 | atomic_dec(&htab->count); | |
398 | return ERR_PTR(-E2BIG); | |
399 | } | |
400 | l_new = kmalloc(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN); | |
401 | if (!l_new) | |
402 | return ERR_PTR(-ENOMEM); | |
403 | } | |
824bd0ce AS |
404 | |
405 | memcpy(l_new->key, key, key_size); | |
406 | if (percpu) { | |
407 | /* round up value_size to 8 bytes */ | |
408 | size = round_up(size, 8); | |
409 | ||
6c905981 AS |
410 | if (prealloc) { |
411 | pptr = htab_elem_get_ptr(l_new, key_size); | |
412 | } else { | |
413 | /* alloc_percpu zero-fills */ | |
414 | pptr = __alloc_percpu_gfp(size, 8, | |
415 | GFP_ATOMIC | __GFP_NOWARN); | |
416 | if (!pptr) { | |
417 | kfree(l_new); | |
418 | return ERR_PTR(-ENOMEM); | |
419 | } | |
824bd0ce AS |
420 | } |
421 | ||
15a07b33 AS |
422 | if (!onallcpus) { |
423 | /* copy true value_size bytes */ | |
424 | memcpy(this_cpu_ptr(pptr), value, htab->map.value_size); | |
425 | } else { | |
426 | int off = 0, cpu; | |
427 | ||
428 | for_each_possible_cpu(cpu) { | |
429 | bpf_long_memcpy(per_cpu_ptr(pptr, cpu), | |
430 | value + off, size); | |
431 | off += size; | |
432 | } | |
433 | } | |
6c905981 AS |
434 | if (!prealloc) |
435 | htab_elem_set_ptr(l_new, key_size, pptr); | |
824bd0ce AS |
436 | } else { |
437 | memcpy(l_new->key + round_up(key_size, 8), value, size); | |
438 | } | |
439 | ||
440 | l_new->hash = hash; | |
441 | return l_new; | |
442 | } | |
443 | ||
444 | static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old, | |
445 | u64 map_flags) | |
446 | { | |
824bd0ce AS |
447 | if (l_old && map_flags == BPF_NOEXIST) |
448 | /* elem already exists */ | |
449 | return -EEXIST; | |
450 | ||
451 | if (!l_old && map_flags == BPF_EXIST) | |
452 | /* elem doesn't exist, cannot update it */ | |
453 | return -ENOENT; | |
454 | ||
455 | return 0; | |
456 | } | |
457 | ||
0f8e4bd8 AS |
458 | /* Called from syscall or from eBPF program */ |
459 | static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, | |
460 | u64 map_flags) | |
461 | { | |
462 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
824bd0ce | 463 | struct htab_elem *l_new = NULL, *l_old; |
0f8e4bd8 AS |
464 | struct hlist_head *head; |
465 | unsigned long flags; | |
824bd0ce AS |
466 | struct bucket *b; |
467 | u32 key_size, hash; | |
0f8e4bd8 AS |
468 | int ret; |
469 | ||
824bd0ce | 470 | if (unlikely(map_flags > BPF_EXIST)) |
0f8e4bd8 AS |
471 | /* unknown flags */ |
472 | return -EINVAL; | |
473 | ||
474 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
475 | ||
0f8e4bd8 AS |
476 | key_size = map->key_size; |
477 | ||
824bd0ce AS |
478 | hash = htab_map_hash(key, key_size); |
479 | ||
824bd0ce | 480 | b = __select_bucket(htab, hash); |
688ecfe6 | 481 | head = &b->head; |
0f8e4bd8 AS |
482 | |
483 | /* bpf_map_update_elem() can be called in_irq() */ | |
688ecfe6 | 484 | raw_spin_lock_irqsave(&b->lock, flags); |
0f8e4bd8 | 485 | |
824bd0ce | 486 | l_old = lookup_elem_raw(head, hash, key, key_size); |
0f8e4bd8 | 487 | |
824bd0ce AS |
488 | ret = check_flags(htab, l_old, map_flags); |
489 | if (ret) | |
0f8e4bd8 | 490 | goto err; |
0f8e4bd8 | 491 | |
6c905981 AS |
492 | l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false); |
493 | if (IS_ERR(l_new)) { | |
494 | /* all pre-allocated elements are in use or memory exhausted */ | |
495 | ret = PTR_ERR(l_new); | |
496 | goto err; | |
497 | } | |
498 | ||
824bd0ce AS |
499 | /* add new element to the head of the list, so that |
500 | * concurrent search will find it before old elem | |
0f8e4bd8 AS |
501 | */ |
502 | hlist_add_head_rcu(&l_new->hash_node, head); | |
503 | if (l_old) { | |
504 | hlist_del_rcu(&l_old->hash_node); | |
6c905981 | 505 | free_htab_elem(htab, l_old); |
0f8e4bd8 | 506 | } |
6c905981 | 507 | ret = 0; |
0f8e4bd8 | 508 | err: |
688ecfe6 | 509 | raw_spin_unlock_irqrestore(&b->lock, flags); |
0f8e4bd8 AS |
510 | return ret; |
511 | } | |
512 | ||
15a07b33 AS |
513 | static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key, |
514 | void *value, u64 map_flags, | |
515 | bool onallcpus) | |
824bd0ce AS |
516 | { |
517 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
518 | struct htab_elem *l_new = NULL, *l_old; | |
519 | struct hlist_head *head; | |
520 | unsigned long flags; | |
521 | struct bucket *b; | |
522 | u32 key_size, hash; | |
523 | int ret; | |
524 | ||
525 | if (unlikely(map_flags > BPF_EXIST)) | |
526 | /* unknown flags */ | |
527 | return -EINVAL; | |
528 | ||
529 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
530 | ||
531 | key_size = map->key_size; | |
532 | ||
533 | hash = htab_map_hash(key, key_size); | |
534 | ||
535 | b = __select_bucket(htab, hash); | |
536 | head = &b->head; | |
537 | ||
538 | /* bpf_map_update_elem() can be called in_irq() */ | |
539 | raw_spin_lock_irqsave(&b->lock, flags); | |
540 | ||
541 | l_old = lookup_elem_raw(head, hash, key, key_size); | |
542 | ||
543 | ret = check_flags(htab, l_old, map_flags); | |
544 | if (ret) | |
545 | goto err; | |
546 | ||
547 | if (l_old) { | |
15a07b33 AS |
548 | void __percpu *pptr = htab_elem_get_ptr(l_old, key_size); |
549 | u32 size = htab->map.value_size; | |
550 | ||
824bd0ce | 551 | /* per-cpu hash map can update value in-place */ |
15a07b33 AS |
552 | if (!onallcpus) { |
553 | memcpy(this_cpu_ptr(pptr), value, size); | |
554 | } else { | |
555 | int off = 0, cpu; | |
556 | ||
557 | size = round_up(size, 8); | |
558 | for_each_possible_cpu(cpu) { | |
559 | bpf_long_memcpy(per_cpu_ptr(pptr, cpu), | |
560 | value + off, size); | |
561 | off += size; | |
562 | } | |
563 | } | |
824bd0ce AS |
564 | } else { |
565 | l_new = alloc_htab_elem(htab, key, value, key_size, | |
15a07b33 | 566 | hash, true, onallcpus); |
6c905981 AS |
567 | if (IS_ERR(l_new)) { |
568 | ret = PTR_ERR(l_new); | |
824bd0ce AS |
569 | goto err; |
570 | } | |
571 | hlist_add_head_rcu(&l_new->hash_node, head); | |
824bd0ce AS |
572 | } |
573 | ret = 0; | |
574 | err: | |
575 | raw_spin_unlock_irqrestore(&b->lock, flags); | |
576 | return ret; | |
577 | } | |
578 | ||
15a07b33 AS |
579 | static int htab_percpu_map_update_elem(struct bpf_map *map, void *key, |
580 | void *value, u64 map_flags) | |
581 | { | |
582 | return __htab_percpu_map_update_elem(map, key, value, map_flags, false); | |
583 | } | |
584 | ||
0f8e4bd8 AS |
585 | /* Called from syscall or from eBPF program */ |
586 | static int htab_map_delete_elem(struct bpf_map *map, void *key) | |
587 | { | |
588 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
589 | struct hlist_head *head; | |
688ecfe6 | 590 | struct bucket *b; |
0f8e4bd8 AS |
591 | struct htab_elem *l; |
592 | unsigned long flags; | |
593 | u32 hash, key_size; | |
594 | int ret = -ENOENT; | |
595 | ||
596 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
597 | ||
598 | key_size = map->key_size; | |
599 | ||
600 | hash = htab_map_hash(key, key_size); | |
688ecfe6 | 601 | b = __select_bucket(htab, hash); |
602 | head = &b->head; | |
0f8e4bd8 | 603 | |
688ecfe6 | 604 | raw_spin_lock_irqsave(&b->lock, flags); |
0f8e4bd8 | 605 | |
0f8e4bd8 AS |
606 | l = lookup_elem_raw(head, hash, key, key_size); |
607 | ||
608 | if (l) { | |
609 | hlist_del_rcu(&l->hash_node); | |
6c905981 | 610 | free_htab_elem(htab, l); |
0f8e4bd8 AS |
611 | ret = 0; |
612 | } | |
613 | ||
688ecfe6 | 614 | raw_spin_unlock_irqrestore(&b->lock, flags); |
0f8e4bd8 AS |
615 | return ret; |
616 | } | |
617 | ||
618 | static void delete_all_elements(struct bpf_htab *htab) | |
619 | { | |
620 | int i; | |
621 | ||
622 | for (i = 0; i < htab->n_buckets; i++) { | |
623 | struct hlist_head *head = select_bucket(htab, i); | |
624 | struct hlist_node *n; | |
625 | struct htab_elem *l; | |
626 | ||
627 | hlist_for_each_entry_safe(l, n, head, hash_node) { | |
628 | hlist_del_rcu(&l->hash_node); | |
6c905981 | 629 | htab_elem_free(htab, l); |
0f8e4bd8 AS |
630 | } |
631 | } | |
632 | } | |
0f8e4bd8 AS |
633 | /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ |
634 | static void htab_map_free(struct bpf_map *map) | |
635 | { | |
636 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
637 | ||
638 | /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, | |
639 | * so the programs (can be more than one that used this map) were | |
640 | * disconnected from events. Wait for outstanding critical sections in | |
641 | * these programs to complete | |
642 | */ | |
643 | synchronize_rcu(); | |
644 | ||
6c905981 AS |
645 | /* some of free_htab_elem() callbacks for elements of this map may |
646 | * not have executed. Wait for them. | |
0f8e4bd8 | 647 | */ |
6c905981 AS |
648 | rcu_barrier(); |
649 | if (htab->map.map_flags & BPF_F_NO_PREALLOC) { | |
650 | delete_all_elements(htab); | |
651 | } else { | |
652 | htab_free_elems(htab); | |
653 | pcpu_freelist_destroy(&htab->freelist); | |
654 | } | |
0f8e4bd8 AS |
655 | kvfree(htab->buckets); |
656 | kfree(htab); | |
657 | } | |
658 | ||
a2c83fff | 659 | static const struct bpf_map_ops htab_ops = { |
0f8e4bd8 AS |
660 | .map_alloc = htab_map_alloc, |
661 | .map_free = htab_map_free, | |
662 | .map_get_next_key = htab_map_get_next_key, | |
663 | .map_lookup_elem = htab_map_lookup_elem, | |
664 | .map_update_elem = htab_map_update_elem, | |
665 | .map_delete_elem = htab_map_delete_elem, | |
666 | }; | |
667 | ||
a2c83fff | 668 | static struct bpf_map_type_list htab_type __read_mostly = { |
0f8e4bd8 AS |
669 | .ops = &htab_ops, |
670 | .type = BPF_MAP_TYPE_HASH, | |
671 | }; | |
672 | ||
824bd0ce AS |
673 | /* Called from eBPF program */ |
674 | static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key) | |
675 | { | |
676 | struct htab_elem *l = __htab_map_lookup_elem(map, key); | |
677 | ||
678 | if (l) | |
679 | return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size)); | |
680 | else | |
681 | return NULL; | |
682 | } | |
683 | ||
15a07b33 AS |
684 | int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value) |
685 | { | |
686 | struct htab_elem *l; | |
687 | void __percpu *pptr; | |
688 | int ret = -ENOENT; | |
689 | int cpu, off = 0; | |
690 | u32 size; | |
691 | ||
692 | /* per_cpu areas are zero-filled and bpf programs can only | |
693 | * access 'value_size' of them, so copying rounded areas | |
694 | * will not leak any kernel data | |
695 | */ | |
696 | size = round_up(map->value_size, 8); | |
697 | rcu_read_lock(); | |
698 | l = __htab_map_lookup_elem(map, key); | |
699 | if (!l) | |
700 | goto out; | |
701 | pptr = htab_elem_get_ptr(l, map->key_size); | |
702 | for_each_possible_cpu(cpu) { | |
703 | bpf_long_memcpy(value + off, | |
704 | per_cpu_ptr(pptr, cpu), size); | |
705 | off += size; | |
706 | } | |
707 | ret = 0; | |
708 | out: | |
709 | rcu_read_unlock(); | |
710 | return ret; | |
711 | } | |
712 | ||
713 | int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, | |
714 | u64 map_flags) | |
715 | { | |
6bbd9a05 SL |
716 | int ret; |
717 | ||
718 | rcu_read_lock(); | |
719 | ret = __htab_percpu_map_update_elem(map, key, value, map_flags, true); | |
720 | rcu_read_unlock(); | |
721 | ||
722 | return ret; | |
15a07b33 AS |
723 | } |
724 | ||
824bd0ce AS |
725 | static const struct bpf_map_ops htab_percpu_ops = { |
726 | .map_alloc = htab_map_alloc, | |
727 | .map_free = htab_map_free, | |
728 | .map_get_next_key = htab_map_get_next_key, | |
729 | .map_lookup_elem = htab_percpu_map_lookup_elem, | |
730 | .map_update_elem = htab_percpu_map_update_elem, | |
731 | .map_delete_elem = htab_map_delete_elem, | |
732 | }; | |
733 | ||
734 | static struct bpf_map_type_list htab_percpu_type __read_mostly = { | |
735 | .ops = &htab_percpu_ops, | |
736 | .type = BPF_MAP_TYPE_PERCPU_HASH, | |
737 | }; | |
738 | ||
0f8e4bd8 AS |
739 | static int __init register_htab_map(void) |
740 | { | |
a2c83fff | 741 | bpf_register_map_type(&htab_type); |
824bd0ce | 742 | bpf_register_map_type(&htab_percpu_type); |
0f8e4bd8 AS |
743 | return 0; |
744 | } | |
745 | late_initcall(register_htab_map); |