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Linux/kernel/bpf/hashtab.c

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  1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  2  * Copyright (c) 2016 Facebook
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of version 2 of the GNU General Public
  6  * License as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful, but
  9  * WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 11  * General Public License for more details.
 12  */
 13 #include <linux/bpf.h>
 14 #include <linux/jhash.h>
 15 #include <linux/filter.h>
 16 #include <linux/rculist_nulls.h>
 17 #include "percpu_freelist.h"
 18 #include "bpf_lru_list.h"
 19 #include "map_in_map.h"
 20 
 21 #define HTAB_CREATE_FLAG_MASK                                           \
 22         (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE |    \
 23          BPF_F_RDONLY | BPF_F_WRONLY)
 24 
 25 struct bucket {
 26         struct hlist_nulls_head head;
 27         raw_spinlock_t lock;
 28 };
 29 
 30 struct bpf_htab {
 31         struct bpf_map map;
 32         struct bucket *buckets;
 33         void *elems;
 34         union {
 35                 struct pcpu_freelist freelist;
 36                 struct bpf_lru lru;
 37         };
 38         struct htab_elem *__percpu *extra_elems;
 39         atomic_t count; /* number of elements in this hashtable */
 40         u32 n_buckets;  /* number of hash buckets */
 41         u32 elem_size;  /* size of each element in bytes */
 42 };
 43 
 44 /* each htab element is struct htab_elem + key + value */
 45 struct htab_elem {
 46         union {
 47                 struct hlist_nulls_node hash_node;
 48                 struct {
 49                         void *padding;
 50                         union {
 51                                 struct bpf_htab *htab;
 52                                 struct pcpu_freelist_node fnode;
 53                         };
 54                 };
 55         };
 56         union {
 57                 struct rcu_head rcu;
 58                 struct bpf_lru_node lru_node;
 59         };
 60         u32 hash;
 61         char key[0] __aligned(8);
 62 };
 63 
 64 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
 65 
 66 static bool htab_is_lru(const struct bpf_htab *htab)
 67 {
 68         return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
 69                 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
 70 }
 71 
 72 static bool htab_is_percpu(const struct bpf_htab *htab)
 73 {
 74         return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
 75                 htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
 76 }
 77 
 78 static bool htab_is_prealloc(const struct bpf_htab *htab)
 79 {
 80         return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
 81 }
 82 
 83 static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
 84                                      void __percpu *pptr)
 85 {
 86         *(void __percpu **)(l->key + key_size) = pptr;
 87 }
 88 
 89 static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
 90 {
 91         return *(void __percpu **)(l->key + key_size);
 92 }
 93 
 94 static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
 95 {
 96         return *(void **)(l->key + roundup(map->key_size, 8));
 97 }
 98 
 99 static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
100 {
101         return (struct htab_elem *) (htab->elems + i * htab->elem_size);
102 }
103 
104 static void htab_free_elems(struct bpf_htab *htab)
105 {
106         int i;
107 
108         if (!htab_is_percpu(htab))
109                 goto free_elems;
110 
111         for (i = 0; i < htab->map.max_entries; i++) {
112                 void __percpu *pptr;
113 
114                 pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
115                                          htab->map.key_size);
116                 free_percpu(pptr);
117                 cond_resched();
118         }
119 free_elems:
120         bpf_map_area_free(htab->elems);
121 }
122 
123 static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
124                                           u32 hash)
125 {
126         struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
127         struct htab_elem *l;
128 
129         if (node) {
130                 l = container_of(node, struct htab_elem, lru_node);
131                 memcpy(l->key, key, htab->map.key_size);
132                 return l;
133         }
134 
135         return NULL;
136 }
137 
138 static int prealloc_init(struct bpf_htab *htab)
139 {
140         u32 num_entries = htab->map.max_entries;
141         int err = -ENOMEM, i;
142 
143         if (!htab_is_percpu(htab) && !htab_is_lru(htab))
144                 num_entries += num_possible_cpus();
145 
146         htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
147                                          htab->map.numa_node);
148         if (!htab->elems)
149                 return -ENOMEM;
150 
151         if (!htab_is_percpu(htab))
152                 goto skip_percpu_elems;
153 
154         for (i = 0; i < num_entries; i++) {
155                 u32 size = round_up(htab->map.value_size, 8);
156                 void __percpu *pptr;
157 
158                 pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
159                 if (!pptr)
160                         goto free_elems;
161                 htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
162                                   pptr);
163                 cond_resched();
164         }
165 
166 skip_percpu_elems:
167         if (htab_is_lru(htab))
168                 err = bpf_lru_init(&htab->lru,
169                                    htab->map.map_flags & BPF_F_NO_COMMON_LRU,
170                                    offsetof(struct htab_elem, hash) -
171                                    offsetof(struct htab_elem, lru_node),
172                                    htab_lru_map_delete_node,
173                                    htab);
174         else
175                 err = pcpu_freelist_init(&htab->freelist);
176 
177         if (err)
178                 goto free_elems;
179 
180         if (htab_is_lru(htab))
181                 bpf_lru_populate(&htab->lru, htab->elems,
182                                  offsetof(struct htab_elem, lru_node),
183                                  htab->elem_size, num_entries);
184         else
185                 pcpu_freelist_populate(&htab->freelist,
186                                        htab->elems + offsetof(struct htab_elem, fnode),
187                                        htab->elem_size, num_entries);
188 
189         return 0;
190 
191 free_elems:
192         htab_free_elems(htab);
193         return err;
194 }
195 
196 static void prealloc_destroy(struct bpf_htab *htab)
197 {
198         htab_free_elems(htab);
199 
200         if (htab_is_lru(htab))
201                 bpf_lru_destroy(&htab->lru);
202         else
203                 pcpu_freelist_destroy(&htab->freelist);
204 }
205 
206 static int alloc_extra_elems(struct bpf_htab *htab)
207 {
208         struct htab_elem *__percpu *pptr, *l_new;
209         struct pcpu_freelist_node *l;
210         int cpu;
211 
212         pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
213                                   GFP_USER | __GFP_NOWARN);
214         if (!pptr)
215                 return -ENOMEM;
216 
217         for_each_possible_cpu(cpu) {
218                 l = pcpu_freelist_pop(&htab->freelist);
219                 /* pop will succeed, since prealloc_init()
220                  * preallocated extra num_possible_cpus elements
221                  */
222                 l_new = container_of(l, struct htab_elem, fnode);
223                 *per_cpu_ptr(pptr, cpu) = l_new;
224         }
225         htab->extra_elems = pptr;
226         return 0;
227 }
228 
229 /* Called from syscall */
230 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
231 {
232         bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
233                        attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
234         bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
235                     attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
236         /* percpu_lru means each cpu has its own LRU list.
237          * it is different from BPF_MAP_TYPE_PERCPU_HASH where
238          * the map's value itself is percpu.  percpu_lru has
239          * nothing to do with the map's value.
240          */
241         bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
242         bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
243         int numa_node = bpf_map_attr_numa_node(attr);
244         struct bpf_htab *htab;
245         int err, i;
246         u64 cost;
247 
248         BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
249                      offsetof(struct htab_elem, hash_node.pprev));
250         BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
251                      offsetof(struct htab_elem, hash_node.pprev));
252 
253         if (lru && !capable(CAP_SYS_ADMIN))
254                 /* LRU implementation is much complicated than other
255                  * maps.  Hence, limit to CAP_SYS_ADMIN for now.
256                  */
257                 return ERR_PTR(-EPERM);
258 
259         if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)
260                 /* reserved bits should not be used */
261                 return ERR_PTR(-EINVAL);
262 
263         if (!lru && percpu_lru)
264                 return ERR_PTR(-EINVAL);
265 
266         if (lru && !prealloc)
267                 return ERR_PTR(-ENOTSUPP);
268 
269         if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
270                 return ERR_PTR(-EINVAL);
271 
272         htab = kzalloc(sizeof(*htab), GFP_USER);
273         if (!htab)
274                 return ERR_PTR(-ENOMEM);
275 
276         /* mandatory map attributes */
277         htab->map.map_type = attr->map_type;
278         htab->map.key_size = attr->key_size;
279         htab->map.value_size = attr->value_size;
280         htab->map.max_entries = attr->max_entries;
281         htab->map.map_flags = attr->map_flags;
282         htab->map.numa_node = numa_node;
283 
284         /* check sanity of attributes.
285          * value_size == 0 may be allowed in the future to use map as a set
286          */
287         err = -EINVAL;
288         if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||
289             htab->map.value_size == 0)
290                 goto free_htab;
291 
292         if (percpu_lru) {
293                 /* ensure each CPU's lru list has >=1 elements.
294                  * since we are at it, make each lru list has the same
295                  * number of elements.
296                  */
297                 htab->map.max_entries = roundup(attr->max_entries,
298                                                 num_possible_cpus());
299                 if (htab->map.max_entries < attr->max_entries)
300                         htab->map.max_entries = rounddown(attr->max_entries,
301                                                           num_possible_cpus());
302         }
303 
304         /* hash table size must be power of 2 */
305         htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
306 
307         err = -E2BIG;
308         if (htab->map.key_size > MAX_BPF_STACK)
309                 /* eBPF programs initialize keys on stack, so they cannot be
310                  * larger than max stack size
311                  */
312                 goto free_htab;
313 
314         if (htab->map.value_size >= KMALLOC_MAX_SIZE -
315             MAX_BPF_STACK - sizeof(struct htab_elem))
316                 /* if value_size is bigger, the user space won't be able to
317                  * access the elements via bpf syscall. This check also makes
318                  * sure that the elem_size doesn't overflow and it's
319                  * kmalloc-able later in htab_map_update_elem()
320                  */
321                 goto free_htab;
322 
323         htab->elem_size = sizeof(struct htab_elem) +
324                           round_up(htab->map.key_size, 8);
325         if (percpu)
326                 htab->elem_size += sizeof(void *);
327         else
328                 htab->elem_size += round_up(htab->map.value_size, 8);
329 
330         /* prevent zero size kmalloc and check for u32 overflow */
331         if (htab->n_buckets == 0 ||
332             htab->n_buckets > U32_MAX / sizeof(struct bucket))
333                 goto free_htab;
334 
335         cost = (u64) htab->n_buckets * sizeof(struct bucket) +
336                (u64) htab->elem_size * htab->map.max_entries;
337 
338         if (percpu)
339                 cost += (u64) round_up(htab->map.value_size, 8) *
340                         num_possible_cpus() * htab->map.max_entries;
341         else
342                cost += (u64) htab->elem_size * num_possible_cpus();
343 
344         if (cost >= U32_MAX - PAGE_SIZE)
345                 /* make sure page count doesn't overflow */
346                 goto free_htab;
347 
348         htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
349 
350         /* if map size is larger than memlock limit, reject it early */
351         err = bpf_map_precharge_memlock(htab->map.pages);
352         if (err)
353                 goto free_htab;
354 
355         err = -ENOMEM;
356         htab->buckets = bpf_map_area_alloc(htab->n_buckets *
357                                            sizeof(struct bucket),
358                                            htab->map.numa_node);
359         if (!htab->buckets)
360                 goto free_htab;
361 
362         for (i = 0; i < htab->n_buckets; i++) {
363                 INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
364                 raw_spin_lock_init(&htab->buckets[i].lock);
365         }
366 
367         if (prealloc) {
368                 err = prealloc_init(htab);
369                 if (err)
370                         goto free_buckets;
371 
372                 if (!percpu && !lru) {
373                         /* lru itself can remove the least used element, so
374                          * there is no need for an extra elem during map_update.
375                          */
376                         err = alloc_extra_elems(htab);
377                         if (err)
378                                 goto free_prealloc;
379                 }
380         }
381 
382         return &htab->map;
383 
384 free_prealloc:
385         prealloc_destroy(htab);
386 free_buckets:
387         bpf_map_area_free(htab->buckets);
388 free_htab:
389         kfree(htab);
390         return ERR_PTR(err);
391 }
392 
393 static inline u32 htab_map_hash(const void *key, u32 key_len)
394 {
395         return jhash(key, key_len, 0);
396 }
397 
398 static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
399 {
400         return &htab->buckets[hash & (htab->n_buckets - 1)];
401 }
402 
403 static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
404 {
405         return &__select_bucket(htab, hash)->head;
406 }
407 
408 /* this lookup function can only be called with bucket lock taken */
409 static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
410                                          void *key, u32 key_size)
411 {
412         struct hlist_nulls_node *n;
413         struct htab_elem *l;
414 
415         hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
416                 if (l->hash == hash && !memcmp(&l->key, key, key_size))
417                         return l;
418 
419         return NULL;
420 }
421 
422 /* can be called without bucket lock. it will repeat the loop in
423  * the unlikely event when elements moved from one bucket into another
424  * while link list is being walked
425  */
426 static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
427                                                u32 hash, void *key,
428                                                u32 key_size, u32 n_buckets)
429 {
430         struct hlist_nulls_node *n;
431         struct htab_elem *l;
432 
433 again:
434         hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
435                 if (l->hash == hash && !memcmp(&l->key, key, key_size))
436                         return l;
437 
438         if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
439                 goto again;
440 
441         return NULL;
442 }
443 
444 /* Called from syscall or from eBPF program directly, so
445  * arguments have to match bpf_map_lookup_elem() exactly.
446  * The return value is adjusted by BPF instructions
447  * in htab_map_gen_lookup().
448  */
449 static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
450 {
451         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
452         struct hlist_nulls_head *head;
453         struct htab_elem *l;
454         u32 hash, key_size;
455 
456         /* Must be called with rcu_read_lock. */
457         WARN_ON_ONCE(!rcu_read_lock_held());
458 
459         key_size = map->key_size;
460 
461         hash = htab_map_hash(key, key_size);
462 
463         head = select_bucket(htab, hash);
464 
465         l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
466 
467         return l;
468 }
469 
470 static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
471 {
472         struct htab_elem *l = __htab_map_lookup_elem(map, key);
473 
474         if (l)
475                 return l->key + round_up(map->key_size, 8);
476 
477         return NULL;
478 }
479 
480 /* inline bpf_map_lookup_elem() call.
481  * Instead of:
482  * bpf_prog
483  *   bpf_map_lookup_elem
484  *     map->ops->map_lookup_elem
485  *       htab_map_lookup_elem
486  *         __htab_map_lookup_elem
487  * do:
488  * bpf_prog
489  *   __htab_map_lookup_elem
490  */
491 static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
492 {
493         struct bpf_insn *insn = insn_buf;
494         const int ret = BPF_REG_0;
495 
496         *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
497         *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
498         *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
499                                 offsetof(struct htab_elem, key) +
500                                 round_up(map->key_size, 8));
501         return insn - insn_buf;
502 }
503 
504 static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
505 {
506         struct htab_elem *l = __htab_map_lookup_elem(map, key);
507 
508         if (l) {
509                 bpf_lru_node_set_ref(&l->lru_node);
510                 return l->key + round_up(map->key_size, 8);
511         }
512 
513         return NULL;
514 }
515 
516 static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
517                                    struct bpf_insn *insn_buf)
518 {
519         struct bpf_insn *insn = insn_buf;
520         const int ret = BPF_REG_0;
521         const int ref_reg = BPF_REG_1;
522 
523         *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
524         *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
525         *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
526                               offsetof(struct htab_elem, lru_node) +
527                               offsetof(struct bpf_lru_node, ref));
528         *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
529         *insn++ = BPF_ST_MEM(BPF_B, ret,
530                              offsetof(struct htab_elem, lru_node) +
531                              offsetof(struct bpf_lru_node, ref),
532                              1);
533         *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
534                                 offsetof(struct htab_elem, key) +
535                                 round_up(map->key_size, 8));
536         return insn - insn_buf;
537 }
538 
539 /* It is called from the bpf_lru_list when the LRU needs to delete
540  * older elements from the htab.
541  */
542 static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
543 {
544         struct bpf_htab *htab = (struct bpf_htab *)arg;
545         struct htab_elem *l = NULL, *tgt_l;
546         struct hlist_nulls_head *head;
547         struct hlist_nulls_node *n;
548         unsigned long flags;
549         struct bucket *b;
550 
551         tgt_l = container_of(node, struct htab_elem, lru_node);
552         b = __select_bucket(htab, tgt_l->hash);
553         head = &b->head;
554 
555         raw_spin_lock_irqsave(&b->lock, flags);
556 
557         hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
558                 if (l == tgt_l) {
559                         hlist_nulls_del_rcu(&l->hash_node);
560                         break;
561                 }
562 
563         raw_spin_unlock_irqrestore(&b->lock, flags);
564 
565         return l == tgt_l;
566 }
567 
568 /* Called from syscall */
569 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
570 {
571         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
572         struct hlist_nulls_head *head;
573         struct htab_elem *l, *next_l;
574         u32 hash, key_size;
575         int i = 0;
576 
577         WARN_ON_ONCE(!rcu_read_lock_held());
578 
579         key_size = map->key_size;
580 
581         if (!key)
582                 goto find_first_elem;
583 
584         hash = htab_map_hash(key, key_size);
585 
586         head = select_bucket(htab, hash);
587 
588         /* lookup the key */
589         l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
590 
591         if (!l)
592                 goto find_first_elem;
593 
594         /* key was found, get next key in the same bucket */
595         next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
596                                   struct htab_elem, hash_node);
597 
598         if (next_l) {
599                 /* if next elem in this hash list is non-zero, just return it */
600                 memcpy(next_key, next_l->key, key_size);
601                 return 0;
602         }
603 
604         /* no more elements in this hash list, go to the next bucket */
605         i = hash & (htab->n_buckets - 1);
606         i++;
607 
608 find_first_elem:
609         /* iterate over buckets */
610         for (; i < htab->n_buckets; i++) {
611                 head = select_bucket(htab, i);
612 
613                 /* pick first element in the bucket */
614                 next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
615                                           struct htab_elem, hash_node);
616                 if (next_l) {
617                         /* if it's not empty, just return it */
618                         memcpy(next_key, next_l->key, key_size);
619                         return 0;
620                 }
621         }
622 
623         /* iterated over all buckets and all elements */
624         return -ENOENT;
625 }
626 
627 static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
628 {
629         if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
630                 free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
631         kfree(l);
632 }
633 
634 static void htab_elem_free_rcu(struct rcu_head *head)
635 {
636         struct htab_elem *l = container_of(head, struct htab_elem, rcu);
637         struct bpf_htab *htab = l->htab;
638 
639         /* must increment bpf_prog_active to avoid kprobe+bpf triggering while
640          * we're calling kfree, otherwise deadlock is possible if kprobes
641          * are placed somewhere inside of slub
642          */
643         preempt_disable();
644         __this_cpu_inc(bpf_prog_active);
645         htab_elem_free(htab, l);
646         __this_cpu_dec(bpf_prog_active);
647         preempt_enable();
648 }
649 
650 static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
651 {
652         struct bpf_map *map = &htab->map;
653 
654         if (map->ops->map_fd_put_ptr) {
655                 void *ptr = fd_htab_map_get_ptr(map, l);
656 
657                 map->ops->map_fd_put_ptr(ptr);
658         }
659 
660         if (htab_is_prealloc(htab)) {
661                 pcpu_freelist_push(&htab->freelist, &l->fnode);
662         } else {
663                 atomic_dec(&htab->count);
664                 l->htab = htab;
665                 call_rcu(&l->rcu, htab_elem_free_rcu);
666         }
667 }
668 
669 static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
670                             void *value, bool onallcpus)
671 {
672         if (!onallcpus) {
673                 /* copy true value_size bytes */
674                 memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
675         } else {
676                 u32 size = round_up(htab->map.value_size, 8);
677                 int off = 0, cpu;
678 
679                 for_each_possible_cpu(cpu) {
680                         bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
681                                         value + off, size);
682                         off += size;
683                 }
684         }
685 }
686 
687 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
688 {
689         return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
690                BITS_PER_LONG == 64;
691 }
692 
693 static u32 htab_size_value(const struct bpf_htab *htab, bool percpu)
694 {
695         u32 size = htab->map.value_size;
696 
697         if (percpu || fd_htab_map_needs_adjust(htab))
698                 size = round_up(size, 8);
699         return size;
700 }
701 
702 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
703                                          void *value, u32 key_size, u32 hash,
704                                          bool percpu, bool onallcpus,
705                                          struct htab_elem *old_elem)
706 {
707         u32 size = htab_size_value(htab, percpu);
708         bool prealloc = htab_is_prealloc(htab);
709         struct htab_elem *l_new, **pl_new;
710         void __percpu *pptr;
711 
712         if (prealloc) {
713                 if (old_elem) {
714                         /* if we're updating the existing element,
715                          * use per-cpu extra elems to avoid freelist_pop/push
716                          */
717                         pl_new = this_cpu_ptr(htab->extra_elems);
718                         l_new = *pl_new;
719                         *pl_new = old_elem;
720                 } else {
721                         struct pcpu_freelist_node *l;
722 
723                         l = pcpu_freelist_pop(&htab->freelist);
724                         if (!l)
725                                 return ERR_PTR(-E2BIG);
726                         l_new = container_of(l, struct htab_elem, fnode);
727                 }
728         } else {
729                 if (atomic_inc_return(&htab->count) > htab->map.max_entries)
730                         if (!old_elem) {
731                                 /* when map is full and update() is replacing
732                                  * old element, it's ok to allocate, since
733                                  * old element will be freed immediately.
734                                  * Otherwise return an error
735                                  */
736                                 atomic_dec(&htab->count);
737                                 return ERR_PTR(-E2BIG);
738                         }
739                 l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
740                                      htab->map.numa_node);
741                 if (!l_new)
742                         return ERR_PTR(-ENOMEM);
743         }
744 
745         memcpy(l_new->key, key, key_size);
746         if (percpu) {
747                 if (prealloc) {
748                         pptr = htab_elem_get_ptr(l_new, key_size);
749                 } else {
750                         /* alloc_percpu zero-fills */
751                         pptr = __alloc_percpu_gfp(size, 8,
752                                                   GFP_ATOMIC | __GFP_NOWARN);
753                         if (!pptr) {
754                                 kfree(l_new);
755                                 return ERR_PTR(-ENOMEM);
756                         }
757                 }
758 
759                 pcpu_copy_value(htab, pptr, value, onallcpus);
760 
761                 if (!prealloc)
762                         htab_elem_set_ptr(l_new, key_size, pptr);
763         } else {
764                 memcpy(l_new->key + round_up(key_size, 8), value, size);
765         }
766 
767         l_new->hash = hash;
768         return l_new;
769 }
770 
771 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
772                        u64 map_flags)
773 {
774         if (l_old && map_flags == BPF_NOEXIST)
775                 /* elem already exists */
776                 return -EEXIST;
777 
778         if (!l_old && map_flags == BPF_EXIST)
779                 /* elem doesn't exist, cannot update it */
780                 return -ENOENT;
781 
782         return 0;
783 }
784 
785 /* Called from syscall or from eBPF program */
786 static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
787                                 u64 map_flags)
788 {
789         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
790         struct htab_elem *l_new = NULL, *l_old;
791         struct hlist_nulls_head *head;
792         unsigned long flags;
793         struct bucket *b;
794         u32 key_size, hash;
795         int ret;
796 
797         if (unlikely(map_flags > BPF_EXIST))
798                 /* unknown flags */
799                 return -EINVAL;
800 
801         WARN_ON_ONCE(!rcu_read_lock_held());
802 
803         key_size = map->key_size;
804 
805         hash = htab_map_hash(key, key_size);
806 
807         b = __select_bucket(htab, hash);
808         head = &b->head;
809 
810         /* bpf_map_update_elem() can be called in_irq() */
811         raw_spin_lock_irqsave(&b->lock, flags);
812 
813         l_old = lookup_elem_raw(head, hash, key, key_size);
814 
815         ret = check_flags(htab, l_old, map_flags);
816         if (ret)
817                 goto err;
818 
819         l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
820                                 l_old);
821         if (IS_ERR(l_new)) {
822                 /* all pre-allocated elements are in use or memory exhausted */
823                 ret = PTR_ERR(l_new);
824                 goto err;
825         }
826 
827         /* add new element to the head of the list, so that
828          * concurrent search will find it before old elem
829          */
830         hlist_nulls_add_head_rcu(&l_new->hash_node, head);
831         if (l_old) {
832                 hlist_nulls_del_rcu(&l_old->hash_node);
833                 if (!htab_is_prealloc(htab))
834                         free_htab_elem(htab, l_old);
835         }
836         ret = 0;
837 err:
838         raw_spin_unlock_irqrestore(&b->lock, flags);
839         return ret;
840 }
841 
842 static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
843                                     u64 map_flags)
844 {
845         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
846         struct htab_elem *l_new, *l_old = NULL;
847         struct hlist_nulls_head *head;
848         unsigned long flags;
849         struct bucket *b;
850         u32 key_size, hash;
851         int ret;
852 
853         if (unlikely(map_flags > BPF_EXIST))
854                 /* unknown flags */
855                 return -EINVAL;
856 
857         WARN_ON_ONCE(!rcu_read_lock_held());
858 
859         key_size = map->key_size;
860 
861         hash = htab_map_hash(key, key_size);
862 
863         b = __select_bucket(htab, hash);
864         head = &b->head;
865 
866         /* For LRU, we need to alloc before taking bucket's
867          * spinlock because getting free nodes from LRU may need
868          * to remove older elements from htab and this removal
869          * operation will need a bucket lock.
870          */
871         l_new = prealloc_lru_pop(htab, key, hash);
872         if (!l_new)
873                 return -ENOMEM;
874         memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
875 
876         /* bpf_map_update_elem() can be called in_irq() */
877         raw_spin_lock_irqsave(&b->lock, flags);
878 
879         l_old = lookup_elem_raw(head, hash, key, key_size);
880 
881         ret = check_flags(htab, l_old, map_flags);
882         if (ret)
883                 goto err;
884 
885         /* add new element to the head of the list, so that
886          * concurrent search will find it before old elem
887          */
888         hlist_nulls_add_head_rcu(&l_new->hash_node, head);
889         if (l_old) {
890                 bpf_lru_node_set_ref(&l_new->lru_node);
891                 hlist_nulls_del_rcu(&l_old->hash_node);
892         }
893         ret = 0;
894 
895 err:
896         raw_spin_unlock_irqrestore(&b->lock, flags);
897 
898         if (ret)
899                 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
900         else if (l_old)
901                 bpf_lru_push_free(&htab->lru, &l_old->lru_node);
902 
903         return ret;
904 }
905 
906 static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
907                                          void *value, u64 map_flags,
908                                          bool onallcpus)
909 {
910         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
911         struct htab_elem *l_new = NULL, *l_old;
912         struct hlist_nulls_head *head;
913         unsigned long flags;
914         struct bucket *b;
915         u32 key_size, hash;
916         int ret;
917 
918         if (unlikely(map_flags > BPF_EXIST))
919                 /* unknown flags */
920                 return -EINVAL;
921 
922         WARN_ON_ONCE(!rcu_read_lock_held());
923 
924         key_size = map->key_size;
925 
926         hash = htab_map_hash(key, key_size);
927 
928         b = __select_bucket(htab, hash);
929         head = &b->head;
930 
931         /* bpf_map_update_elem() can be called in_irq() */
932         raw_spin_lock_irqsave(&b->lock, flags);
933 
934         l_old = lookup_elem_raw(head, hash, key, key_size);
935 
936         ret = check_flags(htab, l_old, map_flags);
937         if (ret)
938                 goto err;
939 
940         if (l_old) {
941                 /* per-cpu hash map can update value in-place */
942                 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
943                                 value, onallcpus);
944         } else {
945                 l_new = alloc_htab_elem(htab, key, value, key_size,
946                                         hash, true, onallcpus, NULL);
947                 if (IS_ERR(l_new)) {
948                         ret = PTR_ERR(l_new);
949                         goto err;
950                 }
951                 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
952         }
953         ret = 0;
954 err:
955         raw_spin_unlock_irqrestore(&b->lock, flags);
956         return ret;
957 }
958 
959 static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
960                                              void *value, u64 map_flags,
961                                              bool onallcpus)
962 {
963         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
964         struct htab_elem *l_new = NULL, *l_old;
965         struct hlist_nulls_head *head;
966         unsigned long flags;
967         struct bucket *b;
968         u32 key_size, hash;
969         int ret;
970 
971         if (unlikely(map_flags > BPF_EXIST))
972                 /* unknown flags */
973                 return -EINVAL;
974 
975         WARN_ON_ONCE(!rcu_read_lock_held());
976 
977         key_size = map->key_size;
978 
979         hash = htab_map_hash(key, key_size);
980 
981         b = __select_bucket(htab, hash);
982         head = &b->head;
983 
984         /* For LRU, we need to alloc before taking bucket's
985          * spinlock because LRU's elem alloc may need
986          * to remove older elem from htab and this removal
987          * operation will need a bucket lock.
988          */
989         if (map_flags != BPF_EXIST) {
990                 l_new = prealloc_lru_pop(htab, key, hash);
991                 if (!l_new)
992                         return -ENOMEM;
993         }
994 
995         /* bpf_map_update_elem() can be called in_irq() */
996         raw_spin_lock_irqsave(&b->lock, flags);
997 
998         l_old = lookup_elem_raw(head, hash, key, key_size);
999 
1000         ret = check_flags(htab, l_old, map_flags);
1001         if (ret)
1002                 goto err;
1003 
1004         if (l_old) {
1005                 bpf_lru_node_set_ref(&l_old->lru_node);
1006 
1007                 /* per-cpu hash map can update value in-place */
1008                 pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1009                                 value, onallcpus);
1010         } else {
1011                 pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
1012                                 value, onallcpus);
1013                 hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1014                 l_new = NULL;
1015         }
1016         ret = 0;
1017 err:
1018         raw_spin_unlock_irqrestore(&b->lock, flags);
1019         if (l_new)
1020                 bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1021         return ret;
1022 }
1023 
1024 static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1025                                        void *value, u64 map_flags)
1026 {
1027         return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1028 }
1029 
1030 static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1031                                            void *value, u64 map_flags)
1032 {
1033         return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1034                                                  false);
1035 }
1036 
1037 /* Called from syscall or from eBPF program */
1038 static int htab_map_delete_elem(struct bpf_map *map, void *key)
1039 {
1040         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1041         struct hlist_nulls_head *head;
1042         struct bucket *b;
1043         struct htab_elem *l;
1044         unsigned long flags;
1045         u32 hash, key_size;
1046         int ret = -ENOENT;
1047 
1048         WARN_ON_ONCE(!rcu_read_lock_held());
1049 
1050         key_size = map->key_size;
1051 
1052         hash = htab_map_hash(key, key_size);
1053         b = __select_bucket(htab, hash);
1054         head = &b->head;
1055 
1056         raw_spin_lock_irqsave(&b->lock, flags);
1057 
1058         l = lookup_elem_raw(head, hash, key, key_size);
1059 
1060         if (l) {
1061                 hlist_nulls_del_rcu(&l->hash_node);
1062                 free_htab_elem(htab, l);
1063                 ret = 0;
1064         }
1065 
1066         raw_spin_unlock_irqrestore(&b->lock, flags);
1067         return ret;
1068 }
1069 
1070 static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1071 {
1072         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1073         struct hlist_nulls_head *head;
1074         struct bucket *b;
1075         struct htab_elem *l;
1076         unsigned long flags;
1077         u32 hash, key_size;
1078         int ret = -ENOENT;
1079 
1080         WARN_ON_ONCE(!rcu_read_lock_held());
1081 
1082         key_size = map->key_size;
1083 
1084         hash = htab_map_hash(key, key_size);
1085         b = __select_bucket(htab, hash);
1086         head = &b->head;
1087 
1088         raw_spin_lock_irqsave(&b->lock, flags);
1089 
1090         l = lookup_elem_raw(head, hash, key, key_size);
1091 
1092         if (l) {
1093                 hlist_nulls_del_rcu(&l->hash_node);
1094                 ret = 0;
1095         }
1096 
1097         raw_spin_unlock_irqrestore(&b->lock, flags);
1098         if (l)
1099                 bpf_lru_push_free(&htab->lru, &l->lru_node);
1100         return ret;
1101 }
1102 
1103 static void delete_all_elements(struct bpf_htab *htab)
1104 {
1105         int i;
1106 
1107         for (i = 0; i < htab->n_buckets; i++) {
1108                 struct hlist_nulls_head *head = select_bucket(htab, i);
1109                 struct hlist_nulls_node *n;
1110                 struct htab_elem *l;
1111 
1112                 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1113                         hlist_nulls_del_rcu(&l->hash_node);
1114                         htab_elem_free(htab, l);
1115                 }
1116         }
1117 }
1118 
1119 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1120 static void htab_map_free(struct bpf_map *map)
1121 {
1122         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1123 
1124         /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
1125          * so the programs (can be more than one that used this map) were
1126          * disconnected from events. Wait for outstanding critical sections in
1127          * these programs to complete
1128          */
1129         synchronize_rcu();
1130 
1131         /* some of free_htab_elem() callbacks for elements of this map may
1132          * not have executed. Wait for them.
1133          */
1134         rcu_barrier();
1135         if (!htab_is_prealloc(htab))
1136                 delete_all_elements(htab);
1137         else
1138                 prealloc_destroy(htab);
1139 
1140         free_percpu(htab->extra_elems);
1141         bpf_map_area_free(htab->buckets);
1142         kfree(htab);
1143 }
1144 
1145 const struct bpf_map_ops htab_map_ops = {
1146         .map_alloc = htab_map_alloc,
1147         .map_free = htab_map_free,
1148         .map_get_next_key = htab_map_get_next_key,
1149         .map_lookup_elem = htab_map_lookup_elem,
1150         .map_update_elem = htab_map_update_elem,
1151         .map_delete_elem = htab_map_delete_elem,
1152         .map_gen_lookup = htab_map_gen_lookup,
1153 };
1154 
1155 const struct bpf_map_ops htab_lru_map_ops = {
1156         .map_alloc = htab_map_alloc,
1157         .map_free = htab_map_free,
1158         .map_get_next_key = htab_map_get_next_key,
1159         .map_lookup_elem = htab_lru_map_lookup_elem,
1160         .map_update_elem = htab_lru_map_update_elem,
1161         .map_delete_elem = htab_lru_map_delete_elem,
1162         .map_gen_lookup = htab_lru_map_gen_lookup,
1163 };
1164 
1165 /* Called from eBPF program */
1166 static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1167 {
1168         struct htab_elem *l = __htab_map_lookup_elem(map, key);
1169 
1170         if (l)
1171                 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1172         else
1173                 return NULL;
1174 }
1175 
1176 static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
1177 {
1178         struct htab_elem *l = __htab_map_lookup_elem(map, key);
1179 
1180         if (l) {
1181                 bpf_lru_node_set_ref(&l->lru_node);
1182                 return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
1183         }
1184 
1185         return NULL;
1186 }
1187 
1188 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
1189 {
1190         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1191         struct htab_elem *l;
1192         void __percpu *pptr;
1193         int ret = -ENOENT;
1194         int cpu, off = 0;
1195         u32 size;
1196 
1197         /* per_cpu areas are zero-filled and bpf programs can only
1198          * access 'value_size' of them, so copying rounded areas
1199          * will not leak any kernel data
1200          */
1201         size = round_up(map->value_size, 8);
1202         rcu_read_lock();
1203         l = __htab_map_lookup_elem(map, key);
1204         if (!l)
1205                 goto out;
1206         if (htab_is_lru(htab))
1207                 bpf_lru_node_set_ref(&l->lru_node);
1208         pptr = htab_elem_get_ptr(l, map->key_size);
1209         for_each_possible_cpu(cpu) {
1210                 bpf_long_memcpy(value + off,
1211                                 per_cpu_ptr(pptr, cpu), size);
1212                 off += size;
1213         }
1214         ret = 0;
1215 out:
1216         rcu_read_unlock();
1217         return ret;
1218 }
1219 
1220 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
1221                            u64 map_flags)
1222 {
1223         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1224         int ret;
1225 
1226         rcu_read_lock();
1227         if (htab_is_lru(htab))
1228                 ret = __htab_lru_percpu_map_update_elem(map, key, value,
1229                                                         map_flags, true);
1230         else
1231                 ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
1232                                                     true);
1233         rcu_read_unlock();
1234 
1235         return ret;
1236 }
1237 
1238 const struct bpf_map_ops htab_percpu_map_ops = {
1239         .map_alloc = htab_map_alloc,
1240         .map_free = htab_map_free,
1241         .map_get_next_key = htab_map_get_next_key,
1242         .map_lookup_elem = htab_percpu_map_lookup_elem,
1243         .map_update_elem = htab_percpu_map_update_elem,
1244         .map_delete_elem = htab_map_delete_elem,
1245 };
1246 
1247 const struct bpf_map_ops htab_lru_percpu_map_ops = {
1248         .map_alloc = htab_map_alloc,
1249         .map_free = htab_map_free,
1250         .map_get_next_key = htab_map_get_next_key,
1251         .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
1252         .map_update_elem = htab_lru_percpu_map_update_elem,
1253         .map_delete_elem = htab_lru_map_delete_elem,
1254 };
1255 
1256 static struct bpf_map *fd_htab_map_alloc(union bpf_attr *attr)
1257 {
1258         if (attr->value_size != sizeof(u32))
1259                 return ERR_PTR(-EINVAL);
1260         return htab_map_alloc(attr);
1261 }
1262 
1263 static void fd_htab_map_free(struct bpf_map *map)
1264 {
1265         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1266         struct hlist_nulls_node *n;
1267         struct hlist_nulls_head *head;
1268         struct htab_elem *l;
1269         int i;
1270 
1271         for (i = 0; i < htab->n_buckets; i++) {
1272                 head = select_bucket(htab, i);
1273 
1274                 hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1275                         void *ptr = fd_htab_map_get_ptr(map, l);
1276 
1277                         map->ops->map_fd_put_ptr(ptr);
1278                 }
1279         }
1280 
1281         htab_map_free(map);
1282 }
1283 
1284 /* only called from syscall */
1285 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
1286 {
1287         void **ptr;
1288         int ret = 0;
1289 
1290         if (!map->ops->map_fd_sys_lookup_elem)
1291                 return -ENOTSUPP;
1292 
1293         rcu_read_lock();
1294         ptr = htab_map_lookup_elem(map, key);
1295         if (ptr)
1296                 *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
1297         else
1298                 ret = -ENOENT;
1299         rcu_read_unlock();
1300 
1301         return ret;
1302 }
1303 
1304 /* only called from syscall */
1305 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
1306                                 void *key, void *value, u64 map_flags)
1307 {
1308         void *ptr;
1309         int ret;
1310         u32 ufd = *(u32 *)value;
1311 
1312         ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
1313         if (IS_ERR(ptr))
1314                 return PTR_ERR(ptr);
1315 
1316         ret = htab_map_update_elem(map, key, &ptr, map_flags);
1317         if (ret)
1318                 map->ops->map_fd_put_ptr(ptr);
1319 
1320         return ret;
1321 }
1322 
1323 static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
1324 {
1325         struct bpf_map *map, *inner_map_meta;
1326 
1327         inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1328         if (IS_ERR(inner_map_meta))
1329                 return inner_map_meta;
1330 
1331         map = fd_htab_map_alloc(attr);
1332         if (IS_ERR(map)) {
1333                 bpf_map_meta_free(inner_map_meta);
1334                 return map;
1335         }
1336 
1337         map->inner_map_meta = inner_map_meta;
1338 
1339         return map;
1340 }
1341 
1342 static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
1343 {
1344         struct bpf_map **inner_map  = htab_map_lookup_elem(map, key);
1345 
1346         if (!inner_map)
1347                 return NULL;
1348 
1349         return READ_ONCE(*inner_map);
1350 }
1351 
1352 static u32 htab_of_map_gen_lookup(struct bpf_map *map,
1353                                   struct bpf_insn *insn_buf)
1354 {
1355         struct bpf_insn *insn = insn_buf;
1356         const int ret = BPF_REG_0;
1357 
1358         *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);
1359         *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
1360         *insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
1361                                 offsetof(struct htab_elem, key) +
1362                                 round_up(map->key_size, 8));
1363         *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1364 
1365         return insn - insn_buf;
1366 }
1367 
1368 static void htab_of_map_free(struct bpf_map *map)
1369 {
1370         bpf_map_meta_free(map->inner_map_meta);
1371         fd_htab_map_free(map);
1372 }
1373 
1374 const struct bpf_map_ops htab_of_maps_map_ops = {
1375         .map_alloc = htab_of_map_alloc,
1376         .map_free = htab_of_map_free,
1377         .map_get_next_key = htab_map_get_next_key,
1378         .map_lookup_elem = htab_of_map_lookup_elem,
1379         .map_delete_elem = htab_map_delete_elem,
1380         .map_fd_get_ptr = bpf_map_fd_get_ptr,
1381         .map_fd_put_ptr = bpf_map_fd_put_ptr,
1382         .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1383         .map_gen_lookup = htab_of_map_gen_lookup,
1384 };
1385 

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