1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 */
5#include <linux/bpf.h>
6#include <linux/btf.h>
7#include <linux/jhash.h>
8#include <linux/filter.h>
9#include <linux/rculist_nulls.h>
10#include <linux/random.h>
11#include <uapi/linux/btf.h>
12#include <linux/rcupdate_trace.h>
13#include <linux/btf_ids.h>
14#include "percpu_freelist.h"
15#include "bpf_lru_list.h"
16#include "map_in_map.h"
17
18#define HTAB_CREATE_FLAG_MASK						\
19	(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE |	\
20	 BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
21
22#define BATCH_OPS(_name)			\
23	.map_lookup_batch =			\
24	_name##_map_lookup_batch,		\
25	.map_lookup_and_delete_batch =		\
26	_name##_map_lookup_and_delete_batch,	\
27	.map_update_batch =			\
28	generic_map_update_batch,		\
29	.map_delete_batch =			\
30	generic_map_delete_batch
31
32/*
33 * The bucket lock has two protection scopes:
34 *
35 * 1) Serializing concurrent operations from BPF programs on different
36 *    CPUs
37 *
38 * 2) Serializing concurrent operations from BPF programs and sys_bpf()
39 *
40 * BPF programs can execute in any context including perf, kprobes and
41 * tracing. As there are almost no limits where perf, kprobes and tracing
42 * can be invoked from the lock operations need to be protected against
43 * deadlocks. Deadlocks can be caused by recursion and by an invocation in
44 * the lock held section when functions which acquire this lock are invoked
45 * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
46 * variable bpf_prog_active, which prevents BPF programs attached to perf
47 * events, kprobes and tracing to be invoked before the prior invocation
48 * from one of these contexts completed. sys_bpf() uses the same mechanism
49 * by pinning the task to the current CPU and incrementing the recursion
50 * protection across the map operation.
51 *
52 * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
53 * operations like memory allocations (even with GFP_ATOMIC) from atomic
54 * contexts. This is required because even with GFP_ATOMIC the memory
55 * allocator calls into code paths which acquire locks with long held lock
56 * sections. To ensure the deterministic behaviour these locks are regular
57 * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
58 * true atomic contexts on an RT kernel are the low level hardware
59 * handling, scheduling, low level interrupt handling, NMIs etc. None of
60 * these contexts should ever do memory allocations.
61 *
62 * As regular device interrupt handlers and soft interrupts are forced into
63 * thread context, the existing code which does
64 *   spin_lock*(); alloc(GFP_ATOMIC); spin_unlock*();
65 * just works.
66 *
67 * In theory the BPF locks could be converted to regular spinlocks as well,
68 * but the bucket locks and percpu_freelist locks can be taken from
69 * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
70 * atomic contexts even on RT. These mechanisms require preallocated maps,
71 * so there is no need to invoke memory allocations within the lock held
72 * sections.
73 *
74 * BPF maps which need dynamic allocation are only used from (forced)
75 * thread context on RT and can therefore use regular spinlocks which in
76 * turn allows to invoke memory allocations from the lock held section.
77 *
78 * On a non RT kernel this distinction is neither possible nor required.
79 * spinlock maps to raw_spinlock and the extra code is optimized out by the
80 * compiler.
81 */
82struct bucket {
83	struct hlist_nulls_head head;
84	union {
85		raw_spinlock_t raw_lock;
86		spinlock_t     lock;
87	};
88};
89
90#define HASHTAB_MAP_LOCK_COUNT 8
91#define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
92
93struct bpf_htab {
94	struct bpf_map map;
95	struct bucket *buckets;
96	void *elems;
97	union {
98		struct pcpu_freelist freelist;
99		struct bpf_lru lru;
100	};
101	struct htab_elem *__percpu *extra_elems;
102	atomic_t count;	/* number of elements in this hashtable */
103	u32 n_buckets;	/* number of hash buckets */
104	u32 elem_size;	/* size of each element in bytes */
105	u32 hashrnd;
106	struct lock_class_key lockdep_key;
107	int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
108};
109
110/* each htab element is struct htab_elem + key + value */
111struct htab_elem {
112	union {
113		struct hlist_nulls_node hash_node;
114		struct {
115			void *padding;
116			union {
117				struct bpf_htab *htab;
118				struct pcpu_freelist_node fnode;
119				struct htab_elem *batch_flink;
120			};
121		};
122	};
123	union {
124		struct rcu_head rcu;
125		struct bpf_lru_node lru_node;
126	};
127	u32 hash;
128	char key[] __aligned(8);
129};
130
131static inline bool htab_is_prealloc(const struct bpf_htab *htab)
132{
133	return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
134}
135
136static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
137{
138	return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
139}
140
141static void htab_init_buckets(struct bpf_htab *htab)
142{
143	unsigned int i;
144
145	for (i = 0; i < htab->n_buckets; i++) {
146		INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
147		if (htab_use_raw_lock(htab)) {
148			raw_spin_lock_init(&htab->buckets[i].raw_lock);
149			lockdep_set_class(&htab->buckets[i].raw_lock,
150					  &htab->lockdep_key);
151		} else {
152			spin_lock_init(&htab->buckets[i].lock);
153			lockdep_set_class(&htab->buckets[i].lock,
154					  &htab->lockdep_key);
155		}
156		cond_resched();
157	}
158}
159
160static inline int htab_lock_bucket(const struct bpf_htab *htab,
161				   struct bucket *b, u32 hash,
162				   unsigned long *pflags)
163{
164	unsigned long flags;
165
166	hash = hash & HASHTAB_MAP_LOCK_MASK;
167
168	migrate_disable();
169	if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
170		__this_cpu_dec(*(htab->map_locked[hash]));
171		migrate_enable();
172		return -EBUSY;
173	}
174
175	if (htab_use_raw_lock(htab))
176		raw_spin_lock_irqsave(&b->raw_lock, flags);
177	else
178		spin_lock_irqsave(&b->lock, flags);
179	*pflags = flags;
180
181	return 0;
182}
183
184static inline void htab_unlock_bucket(const struct bpf_htab *htab,
185				      struct bucket *b, u32 hash,
186				      unsigned long flags)
187{
188	hash = hash & HASHTAB_MAP_LOCK_MASK;
189	if (htab_use_raw_lock(htab))
190		raw_spin_unlock_irqrestore(&b->raw_lock, flags);
191	else
192		spin_unlock_irqrestore(&b->lock, flags);
193	__this_cpu_dec(*(htab->map_locked[hash]));
194	migrate_enable();
195}
196
197static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
198
199static bool htab_is_lru(const struct bpf_htab *htab)
200{
201	return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
202		htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
203}
204
205static bool htab_is_percpu(const struct bpf_htab *htab)
206{
207	return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
208		htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
209}
210
211static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
212				     void __percpu *pptr)
213{
214	*(void __percpu **)(l->key + key_size) = pptr;
215}
216
217static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
218{
219	return *(void __percpu **)(l->key + key_size);
220}
221
222static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
223{
224	return *(void **)(l->key + roundup(map->key_size, 8));
225}
226
227static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
228{
229	return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
230}
231
232static bool htab_has_extra_elems(struct bpf_htab *htab)
233{
234	return !htab_is_percpu(htab) && !htab_is_lru(htab);
235}
236
237static void htab_free_prealloced_timers(struct bpf_htab *htab)
238{
239	u32 num_entries = htab->map.max_entries;
240	int i;
241
242	if (!map_value_has_timer(&htab->map))
243		return;
244	if (htab_has_extra_elems(htab))
245		num_entries += num_possible_cpus();
246
247	for (i = 0; i < num_entries; i++) {
248		struct htab_elem *elem;
249
250		elem = get_htab_elem(htab, i);
251		bpf_timer_cancel_and_free(elem->key +
252					  round_up(htab->map.key_size, 8) +
253					  htab->map.timer_off);
254		cond_resched();
255	}
256}
257
258static void htab_free_prealloced_kptrs(struct bpf_htab *htab)
259{
260	u32 num_entries = htab->map.max_entries;
261	int i;
262
263	if (!map_value_has_kptrs(&htab->map))
264		return;
265	if (htab_has_extra_elems(htab))
266		num_entries += num_possible_cpus();
267
268	for (i = 0; i < num_entries; i++) {
269		struct htab_elem *elem;
270
271		elem = get_htab_elem(htab, i);
272		bpf_map_free_kptrs(&htab->map, elem->key + round_up(htab->map.key_size, 8));
273		cond_resched();
274	}
275}
276
277static void htab_free_elems(struct bpf_htab *htab)
278{
279	int i;
280
281	if (!htab_is_percpu(htab))
282		goto free_elems;
283
284	for (i = 0; i < htab->map.max_entries; i++) {
285		void __percpu *pptr;
286
287		pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
288					 htab->map.key_size);
289		free_percpu(pptr);
290		cond_resched();
291	}
292free_elems:
293	bpf_map_area_free(htab->elems);
294}
295
296/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
297 * (bucket_lock). If both locks need to be acquired together, the lock
298 * order is always lru_lock -> bucket_lock and this only happens in
299 * bpf_lru_list.c logic. For example, certain code path of
300 * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
301 * will acquire lru_lock first followed by acquiring bucket_lock.
302 *
303 * In hashtab.c, to avoid deadlock, lock acquisition of
304 * bucket_lock followed by lru_lock is not allowed. In such cases,
305 * bucket_lock needs to be released first before acquiring lru_lock.
306 */
307static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
308					  u32 hash)
309{
310	struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
311	struct htab_elem *l;
312
313	if (node) {
314		l = container_of(node, struct htab_elem, lru_node);
315		memcpy(l->key, key, htab->map.key_size);
316		return l;
317	}
318
319	return NULL;
320}
321
322static int prealloc_init(struct bpf_htab *htab)
323{
324	u32 num_entries = htab->map.max_entries;
325	int err = -ENOMEM, i;
326
327	if (htab_has_extra_elems(htab))
328		num_entries += num_possible_cpus();
329
330	htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
331					 htab->map.numa_node);
332	if (!htab->elems)
333		return -ENOMEM;
334
335	if (!htab_is_percpu(htab))
336		goto skip_percpu_elems;
337
338	for (i = 0; i < num_entries; i++) {
339		u32 size = round_up(htab->map.value_size, 8);
340		void __percpu *pptr;
341
342		pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
343					    GFP_USER | __GFP_NOWARN);
344		if (!pptr)
345			goto free_elems;
346		htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
347				  pptr);
348		cond_resched();
349	}
350
351skip_percpu_elems:
352	if (htab_is_lru(htab))
353		err = bpf_lru_init(&htab->lru,
354				   htab->map.map_flags & BPF_F_NO_COMMON_LRU,
355				   offsetof(struct htab_elem, hash) -
356				   offsetof(struct htab_elem, lru_node),
357				   htab_lru_map_delete_node,
358				   htab);
359	else
360		err = pcpu_freelist_init(&htab->freelist);
361
362	if (err)
363		goto free_elems;
364
365	if (htab_is_lru(htab))
366		bpf_lru_populate(&htab->lru, htab->elems,
367				 offsetof(struct htab_elem, lru_node),
368				 htab->elem_size, num_entries);
369	else
370		pcpu_freelist_populate(&htab->freelist,
371				       htab->elems + offsetof(struct htab_elem, fnode),
372				       htab->elem_size, num_entries);
373
374	return 0;
375
376free_elems:
377	htab_free_elems(htab);
378	return err;
379}
380
381static void prealloc_destroy(struct bpf_htab *htab)
382{
383	htab_free_elems(htab);
384
385	if (htab_is_lru(htab))
386		bpf_lru_destroy(&htab->lru);
387	else
388		pcpu_freelist_destroy(&htab->freelist);
389}
390
391static int alloc_extra_elems(struct bpf_htab *htab)
392{
393	struct htab_elem *__percpu *pptr, *l_new;
394	struct pcpu_freelist_node *l;
395	int cpu;
396
397	pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
398				    GFP_USER | __GFP_NOWARN);
399	if (!pptr)
400		return -ENOMEM;
401
402	for_each_possible_cpu(cpu) {
403		l = pcpu_freelist_pop(&htab->freelist);
404		/* pop will succeed, since prealloc_init()
405		 * preallocated extra num_possible_cpus elements
406		 */
407		l_new = container_of(l, struct htab_elem, fnode);
408		*per_cpu_ptr(pptr, cpu) = l_new;
409	}
410	htab->extra_elems = pptr;
411	return 0;
412}
413
414/* Called from syscall */
415static int htab_map_alloc_check(union bpf_attr *attr)
416{
417	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
418		       attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
419	bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
420		    attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
421	/* percpu_lru means each cpu has its own LRU list.
422	 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
423	 * the map's value itself is percpu.  percpu_lru has
424	 * nothing to do with the map's value.
425	 */
426	bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
427	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
428	bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
429	int numa_node = bpf_map_attr_numa_node(attr);
430
431	BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
432		     offsetof(struct htab_elem, hash_node.pprev));
433	BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
434		     offsetof(struct htab_elem, hash_node.pprev));
435
436	if (lru && !bpf_capable())
437		/* LRU implementation is much complicated than other
438		 * maps.  Hence, limit to CAP_BPF.
439		 */
440		return -EPERM;
441
442	if (zero_seed && !capable(CAP_SYS_ADMIN))
443		/* Guard against local DoS, and discourage production use. */
444		return -EPERM;
445
446	if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
447	    !bpf_map_flags_access_ok(attr->map_flags))
448		return -EINVAL;
449
450	if (!lru && percpu_lru)
451		return -EINVAL;
452
453	if (lru && !prealloc)
454		return -ENOTSUPP;
455
456	if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
457		return -EINVAL;
458
459	/* check sanity of attributes.
460	 * value_size == 0 may be allowed in the future to use map as a set
461	 */
462	if (attr->max_entries == 0 || attr->key_size == 0 ||
463	    attr->value_size == 0)
464		return -EINVAL;
465
466	if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
467	   sizeof(struct htab_elem))
468		/* if key_size + value_size is bigger, the user space won't be
469		 * able to access the elements via bpf syscall. This check
470		 * also makes sure that the elem_size doesn't overflow and it's
471		 * kmalloc-able later in htab_map_update_elem()
472		 */
473		return -E2BIG;
474
475	return 0;
476}
477
478static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
479{
480	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
481		       attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
482	bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
483		    attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
484	/* percpu_lru means each cpu has its own LRU list.
485	 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
486	 * the map's value itself is percpu.  percpu_lru has
487	 * nothing to do with the map's value.
488	 */
489	bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
490	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
491	struct bpf_htab *htab;
492	int err, i;
493
494	htab = kzalloc(sizeof(*htab), GFP_USER | __GFP_ACCOUNT);
495	if (!htab)
496		return ERR_PTR(-ENOMEM);
497
498	lockdep_register_key(&htab->lockdep_key);
499
500	bpf_map_init_from_attr(&htab->map, attr);
501
502	if (percpu_lru) {
503		/* ensure each CPU's lru list has >=1 elements.
504		 * since we are at it, make each lru list has the same
505		 * number of elements.
506		 */
507		htab->map.max_entries = roundup(attr->max_entries,
508						num_possible_cpus());
509		if (htab->map.max_entries < attr->max_entries)
510			htab->map.max_entries = rounddown(attr->max_entries,
511							  num_possible_cpus());
512	}
513
514	/* hash table size must be power of 2 */
515	htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
516
517	htab->elem_size = sizeof(struct htab_elem) +
518			  round_up(htab->map.key_size, 8);
519	if (percpu)
520		htab->elem_size += sizeof(void *);
521	else
522		htab->elem_size += round_up(htab->map.value_size, 8);
523
524	err = -E2BIG;
525	/* prevent zero size kmalloc and check for u32 overflow */
526	if (htab->n_buckets == 0 ||
527	    htab->n_buckets > U32_MAX / sizeof(struct bucket))
528		goto free_htab;
529
530	err = -ENOMEM;
531	htab->buckets = bpf_map_area_alloc(htab->n_buckets *
532					   sizeof(struct bucket),
533					   htab->map.numa_node);
534	if (!htab->buckets)
535		goto free_htab;
536
537	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
538		htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
539							   sizeof(int),
540							   sizeof(int),
541							   GFP_USER);
542		if (!htab->map_locked[i])
543			goto free_map_locked;
544	}
545
546	if (htab->map.map_flags & BPF_F_ZERO_SEED)
547		htab->hashrnd = 0;
548	else
549		htab->hashrnd = get_random_int();
550
551	htab_init_buckets(htab);
552
553	if (prealloc) {
554		err = prealloc_init(htab);
555		if (err)
556			goto free_map_locked;
557
558		if (!percpu && !lru) {
559			/* lru itself can remove the least used element, so
560			 * there is no need for an extra elem during map_update.
561			 */
562			err = alloc_extra_elems(htab);
563			if (err)
564				goto free_prealloc;
565		}
566	}
567
568	return &htab->map;
569
570free_prealloc:
571	prealloc_destroy(htab);
572free_map_locked:
573	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
574		free_percpu(htab->map_locked[i]);
575	bpf_map_area_free(htab->buckets);
576free_htab:
577	lockdep_unregister_key(&htab->lockdep_key);
578	kfree(htab);
579	return ERR_PTR(err);
580}
581
582static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
583{
584	return jhash(key, key_len, hashrnd);
585}
586
587static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
588{
589	return &htab->buckets[hash & (htab->n_buckets - 1)];
590}
591
592static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
593{
594	return &__select_bucket(htab, hash)->head;
595}
596
597/* this lookup function can only be called with bucket lock taken */
598static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
599					 void *key, u32 key_size)
600{
601	struct hlist_nulls_node *n;
602	struct htab_elem *l;
603
604	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
605		if (l->hash == hash && !memcmp(&l->key, key, key_size))
606			return l;
607
608	return NULL;
609}
610
611/* can be called without bucket lock. it will repeat the loop in
612 * the unlikely event when elements moved from one bucket into another
613 * while link list is being walked
614 */
615static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
616					       u32 hash, void *key,
617					       u32 key_size, u32 n_buckets)
618{
619	struct hlist_nulls_node *n;
620	struct htab_elem *l;
621
622again:
623	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
624		if (l->hash == hash && !memcmp(&l->key, key, key_size))
625			return l;
626
627	if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
628		goto again;
629
630	return NULL;
631}
632
633/* Called from syscall or from eBPF program directly, so
634 * arguments have to match bpf_map_lookup_elem() exactly.
635 * The return value is adjusted by BPF instructions
636 * in htab_map_gen_lookup().
637 */
638static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
639{
640	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
641	struct hlist_nulls_head *head;
642	struct htab_elem *l;
643	u32 hash, key_size;
644
645	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
646		     !rcu_read_lock_bh_held());
647
648	key_size = map->key_size;
649
650	hash = htab_map_hash(key, key_size, htab->hashrnd);
651
652	head = select_bucket(htab, hash);
653
654	l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
655
656	return l;
657}
658
659static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
660{
661	struct htab_elem *l = __htab_map_lookup_elem(map, key);
662
663	if (l)
664		return l->key + round_up(map->key_size, 8);
665
666	return NULL;
667}
668
669/* inline bpf_map_lookup_elem() call.
670 * Instead of:
671 * bpf_prog
672 *   bpf_map_lookup_elem
673 *     map->ops->map_lookup_elem
674 *       htab_map_lookup_elem
675 *         __htab_map_lookup_elem
676 * do:
677 * bpf_prog
678 *   __htab_map_lookup_elem
679 */
680static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
681{
682	struct bpf_insn *insn = insn_buf;
683	const int ret = BPF_REG_0;
684
685	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
686		     (void *(*)(struct bpf_map *map, void *key))NULL));
687	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
688	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
689	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
690				offsetof(struct htab_elem, key) +
691				round_up(map->key_size, 8));
692	return insn - insn_buf;
693}
694
695static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
696							void *key, const bool mark)
697{
698	struct htab_elem *l = __htab_map_lookup_elem(map, key);
699
700	if (l) {
701		if (mark)
702			bpf_lru_node_set_ref(&l->lru_node);
703		return l->key + round_up(map->key_size, 8);
704	}
705
706	return NULL;
707}
708
709static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
710{
711	return __htab_lru_map_lookup_elem(map, key, true);
712}
713
714static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
715{
716	return __htab_lru_map_lookup_elem(map, key, false);
717}
718
719static int htab_lru_map_gen_lookup(struct bpf_map *map,
720				   struct bpf_insn *insn_buf)
721{
722	struct bpf_insn *insn = insn_buf;
723	const int ret = BPF_REG_0;
724	const int ref_reg = BPF_REG_1;
725
726	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
727		     (void *(*)(struct bpf_map *map, void *key))NULL));
728	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
729	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
730	*insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
731			      offsetof(struct htab_elem, lru_node) +
732			      offsetof(struct bpf_lru_node, ref));
733	*insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
734	*insn++ = BPF_ST_MEM(BPF_B, ret,
735			     offsetof(struct htab_elem, lru_node) +
736			     offsetof(struct bpf_lru_node, ref),
737			     1);
738	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
739				offsetof(struct htab_elem, key) +
740				round_up(map->key_size, 8));
741	return insn - insn_buf;
742}
743
744static void check_and_free_fields(struct bpf_htab *htab,
745				  struct htab_elem *elem)
746{
747	void *map_value = elem->key + round_up(htab->map.key_size, 8);
748
749	if (map_value_has_timer(&htab->map))
750		bpf_timer_cancel_and_free(map_value + htab->map.timer_off);
751	if (map_value_has_kptrs(&htab->map))
752		bpf_map_free_kptrs(&htab->map, map_value);
753}
754
755/* It is called from the bpf_lru_list when the LRU needs to delete
756 * older elements from the htab.
757 */
758static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
759{
760	struct bpf_htab *htab = arg;
761	struct htab_elem *l = NULL, *tgt_l;
762	struct hlist_nulls_head *head;
763	struct hlist_nulls_node *n;
764	unsigned long flags;
765	struct bucket *b;
766	int ret;
767
768	tgt_l = container_of(node, struct htab_elem, lru_node);
769	b = __select_bucket(htab, tgt_l->hash);
770	head = &b->head;
771
772	ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
773	if (ret)
774		return false;
775
776	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
777		if (l == tgt_l) {
778			hlist_nulls_del_rcu(&l->hash_node);
779			check_and_free_fields(htab, l);
780			break;
781		}
782
783	htab_unlock_bucket(htab, b, tgt_l->hash, flags);
784
785	return l == tgt_l;
786}
787
788/* Called from syscall */
789static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
790{
791	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
792	struct hlist_nulls_head *head;
793	struct htab_elem *l, *next_l;
794	u32 hash, key_size;
795	int i = 0;
796
797	WARN_ON_ONCE(!rcu_read_lock_held());
798
799	key_size = map->key_size;
800
801	if (!key)
802		goto find_first_elem;
803
804	hash = htab_map_hash(key, key_size, htab->hashrnd);
805
806	head = select_bucket(htab, hash);
807
808	/* lookup the key */
809	l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
810
811	if (!l)
812		goto find_first_elem;
813
814	/* key was found, get next key in the same bucket */
815	next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
816				  struct htab_elem, hash_node);
817
818	if (next_l) {
819		/* if next elem in this hash list is non-zero, just return it */
820		memcpy(next_key, next_l->key, key_size);
821		return 0;
822	}
823
824	/* no more elements in this hash list, go to the next bucket */
825	i = hash & (htab->n_buckets - 1);
826	i++;
827
828find_first_elem:
829	/* iterate over buckets */
830	for (; i < htab->n_buckets; i++) {
831		head = select_bucket(htab, i);
832
833		/* pick first element in the bucket */
834		next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
835					  struct htab_elem, hash_node);
836		if (next_l) {
837			/* if it's not empty, just return it */
838			memcpy(next_key, next_l->key, key_size);
839			return 0;
840		}
841	}
842
843	/* iterated over all buckets and all elements */
844	return -ENOENT;
845}
846
847static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
848{
849	if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
850		free_percpu(htab_elem_get_ptr(l, htab->map.key_size));
851	check_and_free_fields(htab, l);
852	kfree(l);
853}
854
855static void htab_elem_free_rcu(struct rcu_head *head)
856{
857	struct htab_elem *l = container_of(head, struct htab_elem, rcu);
858	struct bpf_htab *htab = l->htab;
859
860	htab_elem_free(htab, l);
861}
862
863static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
864{
865	struct bpf_map *map = &htab->map;
866	void *ptr;
867
868	if (map->ops->map_fd_put_ptr) {
869		ptr = fd_htab_map_get_ptr(map, l);
870		map->ops->map_fd_put_ptr(ptr);
871	}
872}
873
874static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
875{
876	htab_put_fd_value(htab, l);
877
878	if (htab_is_prealloc(htab)) {
879		check_and_free_fields(htab, l);
880		__pcpu_freelist_push(&htab->freelist, &l->fnode);
881	} else {
882		atomic_dec(&htab->count);
883		l->htab = htab;
884		call_rcu(&l->rcu, htab_elem_free_rcu);
885	}
886}
887
888static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
889			    void *value, bool onallcpus)
890{
891	if (!onallcpus) {
892		/* copy true value_size bytes */
893		memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
894	} else {
895		u32 size = round_up(htab->map.value_size, 8);
896		int off = 0, cpu;
897
898		for_each_possible_cpu(cpu) {
899			bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
900					value + off, size);
901			off += size;
902		}
903	}
904}
905
906static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
907			    void *value, bool onallcpus)
908{
909	/* When using prealloc and not setting the initial value on all cpus,
910	 * zero-fill element values for other cpus (just as what happens when
911	 * not using prealloc). Otherwise, bpf program has no way to ensure
912	 * known initial values for cpus other than current one
913	 * (onallcpus=false always when coming from bpf prog).
914	 */
915	if (htab_is_prealloc(htab) && !onallcpus) {
916		u32 size = round_up(htab->map.value_size, 8);
917		int current_cpu = raw_smp_processor_id();
918		int cpu;
919
920		for_each_possible_cpu(cpu) {
921			if (cpu == current_cpu)
922				bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
923						size);
924			else
925				memset(per_cpu_ptr(pptr, cpu), 0, size);
926		}
927	} else {
928		pcpu_copy_value(htab, pptr, value, onallcpus);
929	}
930}
931
932static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
933{
934	return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
935	       BITS_PER_LONG == 64;
936}
937
938static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
939					 void *value, u32 key_size, u32 hash,
940					 bool percpu, bool onallcpus,
941					 struct htab_elem *old_elem)
942{
943	u32 size = htab->map.value_size;
944	bool prealloc = htab_is_prealloc(htab);
945	struct htab_elem *l_new, **pl_new;
946	void __percpu *pptr;
947
948	if (prealloc) {
949		if (old_elem) {
950			/* if we're updating the existing element,
951			 * use per-cpu extra elems to avoid freelist_pop/push
952			 */
953			pl_new = this_cpu_ptr(htab->extra_elems);
954			l_new = *pl_new;
955			htab_put_fd_value(htab, old_elem);
956			*pl_new = old_elem;
957		} else {
958			struct pcpu_freelist_node *l;
959
960			l = __pcpu_freelist_pop(&htab->freelist);
961			if (!l)
962				return ERR_PTR(-E2BIG);
963			l_new = container_of(l, struct htab_elem, fnode);
964		}
965	} else {
966		if (atomic_inc_return(&htab->count) > htab->map.max_entries)
967			if (!old_elem) {
968				/* when map is full and update() is replacing
969				 * old element, it's ok to allocate, since
970				 * old element will be freed immediately.
971				 * Otherwise return an error
972				 */
973				l_new = ERR_PTR(-E2BIG);
974				goto dec_count;
975			}
976		l_new = bpf_map_kmalloc_node(&htab->map, htab->elem_size,
977					     GFP_NOWAIT | __GFP_NOWARN,
978					     htab->map.numa_node);
979		if (!l_new) {
980			l_new = ERR_PTR(-ENOMEM);
981			goto dec_count;
982		}
983		check_and_init_map_value(&htab->map,
984					 l_new->key + round_up(key_size, 8));
985	}
986
987	memcpy(l_new->key, key, key_size);
988	if (percpu) {
989		size = round_up(size, 8);
990		if (prealloc) {
991			pptr = htab_elem_get_ptr(l_new, key_size);
992		} else {
993			/* alloc_percpu zero-fills */
994			pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
995						    GFP_NOWAIT | __GFP_NOWARN);
996			if (!pptr) {
997				kfree(l_new);
998				l_new = ERR_PTR(-ENOMEM);
999				goto dec_count;
1000			}
1001		}
1002
1003		pcpu_init_value(htab, pptr, value, onallcpus);
1004
1005		if (!prealloc)
1006			htab_elem_set_ptr(l_new, key_size, pptr);
1007	} else if (fd_htab_map_needs_adjust(htab)) {
1008		size = round_up(size, 8);
1009		memcpy(l_new->key + round_up(key_size, 8), value, size);
1010	} else {
1011		copy_map_value(&htab->map,
1012			       l_new->key + round_up(key_size, 8),
1013			       value);
1014	}
1015
1016	l_new->hash = hash;
1017	return l_new;
1018dec_count:
1019	atomic_dec(&htab->count);
1020	return l_new;
1021}
1022
1023static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
1024		       u64 map_flags)
1025{
1026	if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
1027		/* elem already exists */
1028		return -EEXIST;
1029
1030	if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
1031		/* elem doesn't exist, cannot update it */
1032		return -ENOENT;
1033
1034	return 0;
1035}
1036
1037/* Called from syscall or from eBPF program */
1038static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
1039				u64 map_flags)
1040{
1041	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1042	struct htab_elem *l_new = NULL, *l_old;
1043	struct hlist_nulls_head *head;
1044	unsigned long flags;
1045	struct bucket *b;
1046	u32 key_size, hash;
1047	int ret;
1048
1049	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
1050		/* unknown flags */
1051		return -EINVAL;
1052
1053	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1054		     !rcu_read_lock_bh_held());
1055
1056	key_size = map->key_size;
1057
1058	hash = htab_map_hash(key, key_size, htab->hashrnd);
1059
1060	b = __select_bucket(htab, hash);
1061	head = &b->head;
1062
1063	if (unlikely(map_flags & BPF_F_LOCK)) {
1064		if (unlikely(!map_value_has_spin_lock(map)))
1065			return -EINVAL;
1066		/* find an element without taking the bucket lock */
1067		l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
1068					      htab->n_buckets);
1069		ret = check_flags(htab, l_old, map_flags);
1070		if (ret)
1071			return ret;
1072		if (l_old) {
1073			/* grab the element lock and update value in place */
1074			copy_map_value_locked(map,
1075					      l_old->key + round_up(key_size, 8),
1076					      value, false);
1077			return 0;
1078		}
1079		/* fall through, grab the bucket lock and lookup again.
1080		 * 99.9% chance that the element won't be found,
1081		 * but second lookup under lock has to be done.
1082		 */
1083	}
1084
1085	ret = htab_lock_bucket(htab, b, hash, &flags);
1086	if (ret)
1087		return ret;
1088
1089	l_old = lookup_elem_raw(head, hash, key, key_size);
1090
1091	ret = check_flags(htab, l_old, map_flags);
1092	if (ret)
1093		goto err;
1094
1095	if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
1096		/* first lookup without the bucket lock didn't find the element,
1097		 * but second lookup with the bucket lock found it.
1098		 * This case is highly unlikely, but has to be dealt with:
1099		 * grab the element lock in addition to the bucket lock
1100		 * and update element in place
1101		 */
1102		copy_map_value_locked(map,
1103				      l_old->key + round_up(key_size, 8),
1104				      value, false);
1105		ret = 0;
1106		goto err;
1107	}
1108
1109	l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
1110				l_old);
1111	if (IS_ERR(l_new)) {
1112		/* all pre-allocated elements are in use or memory exhausted */
1113		ret = PTR_ERR(l_new);
1114		goto err;
1115	}
1116
1117	/* add new element to the head of the list, so that
1118	 * concurrent search will find it before old elem
1119	 */
1120	hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1121	if (l_old) {
1122		hlist_nulls_del_rcu(&l_old->hash_node);
1123		if (!htab_is_prealloc(htab))
1124			free_htab_elem(htab, l_old);
1125		else
1126			check_and_free_fields(htab, l_old);
1127	}
1128	ret = 0;
1129err:
1130	htab_unlock_bucket(htab, b, hash, flags);
1131	return ret;
1132}
1133
1134static void htab_lru_push_free(struct bpf_htab *htab, struct htab_elem *elem)
1135{
1136	check_and_free_fields(htab, elem);
1137	bpf_lru_push_free(&htab->lru, &elem->lru_node);
1138}
1139
1140static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
1141				    u64 map_flags)
1142{
1143	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1144	struct htab_elem *l_new, *l_old = NULL;
1145	struct hlist_nulls_head *head;
1146	unsigned long flags;
1147	struct bucket *b;
1148	u32 key_size, hash;
1149	int ret;
1150
1151	if (unlikely(map_flags > BPF_EXIST))
1152		/* unknown flags */
1153		return -EINVAL;
1154
1155	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1156		     !rcu_read_lock_bh_held());
1157
1158	key_size = map->key_size;
1159
1160	hash = htab_map_hash(key, key_size, htab->hashrnd);
1161
1162	b = __select_bucket(htab, hash);
1163	head = &b->head;
1164
1165	/* For LRU, we need to alloc before taking bucket's
1166	 * spinlock because getting free nodes from LRU may need
1167	 * to remove older elements from htab and this removal
1168	 * operation will need a bucket lock.
1169	 */
1170	l_new = prealloc_lru_pop(htab, key, hash);
1171	if (!l_new)
1172		return -ENOMEM;
1173	copy_map_value(&htab->map,
1174		       l_new->key + round_up(map->key_size, 8), value);
1175
1176	ret = htab_lock_bucket(htab, b, hash, &flags);
1177	if (ret)
1178		return ret;
1179
1180	l_old = lookup_elem_raw(head, hash, key, key_size);
1181
1182	ret = check_flags(htab, l_old, map_flags);
1183	if (ret)
1184		goto err;
1185
1186	/* add new element to the head of the list, so that
1187	 * concurrent search will find it before old elem
1188	 */
1189	hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1190	if (l_old) {
1191		bpf_lru_node_set_ref(&l_new->lru_node);
1192		hlist_nulls_del_rcu(&l_old->hash_node);
1193	}
1194	ret = 0;
1195
1196err:
1197	htab_unlock_bucket(htab, b, hash, flags);
1198
1199	if (ret)
1200		htab_lru_push_free(htab, l_new);
1201	else if (l_old)
1202		htab_lru_push_free(htab, l_old);
1203
1204	return ret;
1205}
1206
1207static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1208					 void *value, u64 map_flags,
1209					 bool onallcpus)
1210{
1211	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1212	struct htab_elem *l_new = NULL, *l_old;
1213	struct hlist_nulls_head *head;
1214	unsigned long flags;
1215	struct bucket *b;
1216	u32 key_size, hash;
1217	int ret;
1218
1219	if (unlikely(map_flags > BPF_EXIST))
1220		/* unknown flags */
1221		return -EINVAL;
1222
1223	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1224		     !rcu_read_lock_bh_held());
1225
1226	key_size = map->key_size;
1227
1228	hash = htab_map_hash(key, key_size, htab->hashrnd);
1229
1230	b = __select_bucket(htab, hash);
1231	head = &b->head;
1232
1233	ret = htab_lock_bucket(htab, b, hash, &flags);
1234	if (ret)
1235		return ret;
1236
1237	l_old = lookup_elem_raw(head, hash, key, key_size);
1238
1239	ret = check_flags(htab, l_old, map_flags);
1240	if (ret)
1241		goto err;
1242
1243	if (l_old) {
1244		/* per-cpu hash map can update value in-place */
1245		pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1246				value, onallcpus);
1247	} else {
1248		l_new = alloc_htab_elem(htab, key, value, key_size,
1249					hash, true, onallcpus, NULL);
1250		if (IS_ERR(l_new)) {
1251			ret = PTR_ERR(l_new);
1252			goto err;
1253		}
1254		hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1255	}
1256	ret = 0;
1257err:
1258	htab_unlock_bucket(htab, b, hash, flags);
1259	return ret;
1260}
1261
1262static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1263					     void *value, u64 map_flags,
1264					     bool onallcpus)
1265{
1266	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1267	struct htab_elem *l_new = NULL, *l_old;
1268	struct hlist_nulls_head *head;
1269	unsigned long flags;
1270	struct bucket *b;
1271	u32 key_size, hash;
1272	int ret;
1273
1274	if (unlikely(map_flags > BPF_EXIST))
1275		/* unknown flags */
1276		return -EINVAL;
1277
1278	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1279		     !rcu_read_lock_bh_held());
1280
1281	key_size = map->key_size;
1282
1283	hash = htab_map_hash(key, key_size, htab->hashrnd);
1284
1285	b = __select_bucket(htab, hash);
1286	head = &b->head;
1287
1288	/* For LRU, we need to alloc before taking bucket's
1289	 * spinlock because LRU's elem alloc may need
1290	 * to remove older elem from htab and this removal
1291	 * operation will need a bucket lock.
1292	 */
1293	if (map_flags != BPF_EXIST) {
1294		l_new = prealloc_lru_pop(htab, key, hash);
1295		if (!l_new)
1296			return -ENOMEM;
1297	}
1298
1299	ret = htab_lock_bucket(htab, b, hash, &flags);
1300	if (ret)
1301		return ret;
1302
1303	l_old = lookup_elem_raw(head, hash, key, key_size);
1304
1305	ret = check_flags(htab, l_old, map_flags);
1306	if (ret)
1307		goto err;
1308
1309	if (l_old) {
1310		bpf_lru_node_set_ref(&l_old->lru_node);
1311
1312		/* per-cpu hash map can update value in-place */
1313		pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
1314				value, onallcpus);
1315	} else {
1316		pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
1317				value, onallcpus);
1318		hlist_nulls_add_head_rcu(&l_new->hash_node, head);
1319		l_new = NULL;
1320	}
1321	ret = 0;
1322err:
1323	htab_unlock_bucket(htab, b, hash, flags);
1324	if (l_new)
1325		bpf_lru_push_free(&htab->lru, &l_new->lru_node);
1326	return ret;
1327}
1328
1329static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
1330				       void *value, u64 map_flags)
1331{
1332	return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
1333}
1334
1335static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
1336					   void *value, u64 map_flags)
1337{
1338	return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
1339						 false);
1340}
1341
1342/* Called from syscall or from eBPF program */
1343static int htab_map_delete_elem(struct bpf_map *map, void *key)
1344{
1345	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1346	struct hlist_nulls_head *head;
1347	struct bucket *b;
1348	struct htab_elem *l;
1349	unsigned long flags;
1350	u32 hash, key_size;
1351	int ret;
1352
1353	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1354		     !rcu_read_lock_bh_held());
1355
1356	key_size = map->key_size;
1357
1358	hash = htab_map_hash(key, key_size, htab->hashrnd);
1359	b = __select_bucket(htab, hash);
1360	head = &b->head;
1361
1362	ret = htab_lock_bucket(htab, b, hash, &flags);
1363	if (ret)
1364		return ret;
1365
1366	l = lookup_elem_raw(head, hash, key, key_size);
1367
1368	if (l) {
1369		hlist_nulls_del_rcu(&l->hash_node);
1370		free_htab_elem(htab, l);
1371	} else {
1372		ret = -ENOENT;
1373	}
1374
1375	htab_unlock_bucket(htab, b, hash, flags);
1376	return ret;
1377}
1378
1379static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
1380{
1381	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1382	struct hlist_nulls_head *head;
1383	struct bucket *b;
1384	struct htab_elem *l;
1385	unsigned long flags;
1386	u32 hash, key_size;
1387	int ret;
1388
1389	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
1390		     !rcu_read_lock_bh_held());
1391
1392	key_size = map->key_size;
1393
1394	hash = htab_map_hash(key, key_size, htab->hashrnd);
1395	b = __select_bucket(htab, hash);
1396	head = &b->head;
1397
1398	ret = htab_lock_bucket(htab, b, hash, &flags);
1399	if (ret)
1400		return ret;
1401
1402	l = lookup_elem_raw(head, hash, key, key_size);
1403
1404	if (l)
1405		hlist_nulls_del_rcu(&l->hash_node);
1406	else
1407		ret = -ENOENT;
1408
1409	htab_unlock_bucket(htab, b, hash, flags);
1410	if (l)
1411		htab_lru_push_free(htab, l);
1412	return ret;
1413}
1414
1415static void delete_all_elements(struct bpf_htab *htab)
1416{
1417	int i;
1418
1419	for (i = 0; i < htab->n_buckets; i++) {
1420		struct hlist_nulls_head *head = select_bucket(htab, i);
1421		struct hlist_nulls_node *n;
1422		struct htab_elem *l;
1423
1424		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1425			hlist_nulls_del_rcu(&l->hash_node);
1426			htab_elem_free(htab, l);
1427		}
1428	}
1429}
1430
1431static void htab_free_malloced_timers(struct bpf_htab *htab)
1432{
1433	int i;
1434
1435	rcu_read_lock();
1436	for (i = 0; i < htab->n_buckets; i++) {
1437		struct hlist_nulls_head *head = select_bucket(htab, i);
1438		struct hlist_nulls_node *n;
1439		struct htab_elem *l;
1440
1441		hlist_nulls_for_each_entry(l, n, head, hash_node) {
1442			/* We don't reset or free kptr on uref dropping to zero,
1443			 * hence just free timer.
1444			 */
1445			bpf_timer_cancel_and_free(l->key +
1446						  round_up(htab->map.key_size, 8) +
1447						  htab->map.timer_off);
1448		}
1449		cond_resched_rcu();
1450	}
1451	rcu_read_unlock();
1452}
1453
1454static void htab_map_free_timers(struct bpf_map *map)
1455{
1456	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1457
1458	/* We don't reset or free kptr on uref dropping to zero. */
1459	if (!map_value_has_timer(&htab->map))
1460		return;
1461	if (!htab_is_prealloc(htab))
1462		htab_free_malloced_timers(htab);
1463	else
1464		htab_free_prealloced_timers(htab);
1465}
1466
1467/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
1468static void htab_map_free(struct bpf_map *map)
1469{
1470	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1471	int i;
1472
1473	/* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
1474	 * bpf_free_used_maps() is called after bpf prog is no longer executing.
1475	 * There is no need to synchronize_rcu() here to protect map elements.
1476	 */
1477
1478	/* some of free_htab_elem() callbacks for elements of this map may
1479	 * not have executed. Wait for them.
1480	 */
1481	rcu_barrier();
1482	if (!htab_is_prealloc(htab)) {
1483		delete_all_elements(htab);
1484	} else {
1485		htab_free_prealloced_kptrs(htab);
1486		prealloc_destroy(htab);
1487	}
1488
1489	bpf_map_free_kptr_off_tab(map);
1490	free_percpu(htab->extra_elems);
1491	bpf_map_area_free(htab->buckets);
1492	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
1493		free_percpu(htab->map_locked[i]);
1494	lockdep_unregister_key(&htab->lockdep_key);
1495	kfree(htab);
1496}
1497
1498static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
1499				   struct seq_file *m)
1500{
1501	void *value;
1502
1503	rcu_read_lock();
1504
1505	value = htab_map_lookup_elem(map, key);
1506	if (!value) {
1507		rcu_read_unlock();
1508		return;
1509	}
1510
1511	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
1512	seq_puts(m, ": ");
1513	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
1514	seq_puts(m, "\n");
1515
1516	rcu_read_unlock();
1517}
1518
1519static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1520					     void *value, bool is_lru_map,
1521					     bool is_percpu, u64 flags)
1522{
1523	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1524	struct hlist_nulls_head *head;
1525	unsigned long bflags;
1526	struct htab_elem *l;
1527	u32 hash, key_size;
1528	struct bucket *b;
1529	int ret;
1530
1531	key_size = map->key_size;
1532
1533	hash = htab_map_hash(key, key_size, htab->hashrnd);
1534	b = __select_bucket(htab, hash);
1535	head = &b->head;
1536
1537	ret = htab_lock_bucket(htab, b, hash, &bflags);
1538	if (ret)
1539		return ret;
1540
1541	l = lookup_elem_raw(head, hash, key, key_size);
1542	if (!l) {
1543		ret = -ENOENT;
1544	} else {
1545		if (is_percpu) {
1546			u32 roundup_value_size = round_up(map->value_size, 8);
1547			void __percpu *pptr;
1548			int off = 0, cpu;
1549
1550			pptr = htab_elem_get_ptr(l, key_size);
1551			for_each_possible_cpu(cpu) {
1552				bpf_long_memcpy(value + off,
1553						per_cpu_ptr(pptr, cpu),
1554						roundup_value_size);
1555				off += roundup_value_size;
1556			}
1557		} else {
1558			u32 roundup_key_size = round_up(map->key_size, 8);
1559
1560			if (flags & BPF_F_LOCK)
1561				copy_map_value_locked(map, value, l->key +
1562						      roundup_key_size,
1563						      true);
1564			else
1565				copy_map_value(map, value, l->key +
1566					       roundup_key_size);
1567			check_and_init_map_value(map, value);
1568		}
1569
1570		hlist_nulls_del_rcu(&l->hash_node);
1571		if (!is_lru_map)
1572			free_htab_elem(htab, l);
1573	}
1574
1575	htab_unlock_bucket(htab, b, hash, bflags);
1576
1577	if (is_lru_map && l)
1578		htab_lru_push_free(htab, l);
1579
1580	return ret;
1581}
1582
1583static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1584					   void *value, u64 flags)
1585{
1586	return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
1587						 flags);
1588}
1589
1590static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1591						  void *key, void *value,
1592						  u64 flags)
1593{
1594	return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
1595						 flags);
1596}
1597
1598static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
1599					       void *value, u64 flags)
1600{
1601	return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
1602						 flags);
1603}
1604
1605static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
1606						      void *key, void *value,
1607						      u64 flags)
1608{
1609	return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
1610						 flags);
1611}
1612
1613static int
1614__htab_map_lookup_and_delete_batch(struct bpf_map *map,
1615				   const union bpf_attr *attr,
1616				   union bpf_attr __user *uattr,
1617				   bool do_delete, bool is_lru_map,
1618				   bool is_percpu)
1619{
1620	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
1621	u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
1622	void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
1623	void __user *uvalues = u64_to_user_ptr(attr->batch.values);
1624	void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
1625	void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
1626	u32 batch, max_count, size, bucket_size, map_id;
1627	struct htab_elem *node_to_free = NULL;
1628	u64 elem_map_flags, map_flags;
1629	struct hlist_nulls_head *head;
1630	struct hlist_nulls_node *n;
1631	unsigned long flags = 0;
1632	bool locked = false;
1633	struct htab_elem *l;
1634	struct bucket *b;
1635	int ret = 0;
1636
1637	elem_map_flags = attr->batch.elem_flags;
1638	if ((elem_map_flags & ~BPF_F_LOCK) ||
1639	    ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
1640		return -EINVAL;
1641
1642	map_flags = attr->batch.flags;
1643	if (map_flags)
1644		return -EINVAL;
1645
1646	max_count = attr->batch.count;
1647	if (!max_count)
1648		return 0;
1649
1650	if (put_user(0, &uattr->batch.count))
1651		return -EFAULT;
1652
1653	batch = 0;
1654	if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
1655		return -EFAULT;
1656
1657	if (batch >= htab->n_buckets)
1658		return -ENOENT;
1659
1660	key_size = htab->map.key_size;
1661	roundup_key_size = round_up(htab->map.key_size, 8);
1662	value_size = htab->map.value_size;
1663	size = round_up(value_size, 8);
1664	if (is_percpu)
1665		value_size = size * num_possible_cpus();
1666	total = 0;
1667	/* while experimenting with hash tables with sizes ranging from 10 to
1668	 * 1000, it was observed that a bucket can have up to 5 entries.
1669	 */
1670	bucket_size = 5;
1671
1672alloc:
1673	/* We cannot do copy_from_user or copy_to_user inside
1674	 * the rcu_read_lock. Allocate enough space here.
1675	 */
1676	keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
1677	values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
1678	if (!keys || !values) {
1679		ret = -ENOMEM;
1680		goto after_loop;
1681	}
1682
1683again:
1684	bpf_disable_instrumentation();
1685	rcu_read_lock();
1686again_nocopy:
1687	dst_key = keys;
1688	dst_val = values;
1689	b = &htab->buckets[batch];
1690	head = &b->head;
1691	/* do not grab the lock unless need it (bucket_cnt > 0). */
1692	if (locked) {
1693		ret = htab_lock_bucket(htab, b, batch, &flags);
1694		if (ret)
1695			goto next_batch;
1696	}
1697
1698	bucket_cnt = 0;
1699	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
1700		bucket_cnt++;
1701
1702	if (bucket_cnt && !locked) {
1703		locked = true;
1704		goto again_nocopy;
1705	}
1706
1707	if (bucket_cnt > (max_count - total)) {
1708		if (total == 0)
1709			ret = -ENOSPC;
1710		/* Note that since bucket_cnt > 0 here, it is implicit
1711		 * that the locked was grabbed, so release it.
1712		 */
1713		htab_unlock_bucket(htab, b, batch, flags);
1714		rcu_read_unlock();
1715		bpf_enable_instrumentation();
1716		goto after_loop;
1717	}
1718
1719	if (bucket_cnt > bucket_size) {
1720		bucket_size = bucket_cnt;
1721		/* Note that since bucket_cnt > 0 here, it is implicit
1722		 * that the locked was grabbed, so release it.
1723		 */
1724		htab_unlock_bucket(htab, b, batch, flags);
1725		rcu_read_unlock();
1726		bpf_enable_instrumentation();
1727		kvfree(keys);
1728		kvfree(values);
1729		goto alloc;
1730	}
1731
1732	/* Next block is only safe to run if you have grabbed the lock */
1733	if (!locked)
1734		goto next_batch;
1735
1736	hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
1737		memcpy(dst_key, l->key, key_size);
1738
1739		if (is_percpu) {
1740			int off = 0, cpu;
1741			void __percpu *pptr;
1742
1743			pptr = htab_elem_get_ptr(l, map->key_size);
1744			for_each_possible_cpu(cpu) {
1745				bpf_long_memcpy(dst_val + off,
1746						per_cpu_ptr(pptr, cpu), size);
1747				off += size;
1748			}
1749		} else {
1750			value = l->key + roundup_key_size;
1751			if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
1752				struct bpf_map **inner_map = value;
1753
1754				 /* Actual value is the id of the inner map */
1755				map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
1756				value = &map_id;
1757			}
1758
1759			if (elem_map_flags & BPF_F_LOCK)
1760				copy_map_value_locked(map, dst_val, value,
1761						      true);
1762			else
1763				copy_map_value(map, dst_val, value);
1764			check_and_init_map_value(map, dst_val);
1765		}
1766		if (do_delete) {
1767			hlist_nulls_del_rcu(&l->hash_node);
1768
1769			/* bpf_lru_push_free() will acquire lru_lock, which
1770			 * may cause deadlock. See comments in function
1771			 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
1772			 * after releasing the bucket lock.
1773			 */
1774			if (is_lru_map) {
1775				l->batch_flink = node_to_free;
1776				node_to_free = l;
1777			} else {
1778				free_htab_elem(htab, l);
1779			}
1780		}
1781		dst_key += key_size;
1782		dst_val += value_size;
1783	}
1784
1785	htab_unlock_bucket(htab, b, batch, flags);
1786	locked = false;
1787
1788	while (node_to_free) {
1789		l = node_to_free;
1790		node_to_free = node_to_free->batch_flink;
1791		htab_lru_push_free(htab, l);
1792	}
1793
1794next_batch:
1795	/* If we are not copying data, we can go to next bucket and avoid
1796	 * unlocking the rcu.
1797	 */
1798	if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
1799		batch++;
1800		goto again_nocopy;
1801	}
1802
1803	rcu_read_unlock();
1804	bpf_enable_instrumentation();
1805	if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
1806	    key_size * bucket_cnt) ||
1807	    copy_to_user(uvalues + total * value_size, values,
1808	    value_size * bucket_cnt))) {
1809		ret = -EFAULT;
1810		goto after_loop;
1811	}
1812
1813	total += bucket_cnt;
1814	batch++;
1815	if (batch >= htab->n_buckets) {
1816		ret = -ENOENT;
1817		goto after_loop;
1818	}
1819	goto again;
1820
1821after_loop:
1822	if (ret == -EFAULT)
1823		goto out;
1824
1825	/* copy # of entries and next batch */
1826	ubatch = u64_to_user_ptr(attr->batch.out_batch);
1827	if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
1828	    put_user(total, &uattr->batch.count))
1829		ret = -EFAULT;
1830
1831out:
1832	kvfree(keys);
1833	kvfree(values);
1834	return ret;
1835}
1836
1837static int
1838htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1839			     union bpf_attr __user *uattr)
1840{
1841	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1842						  false, true);
1843}
1844
1845static int
1846htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1847					const union bpf_attr *attr,
1848					union bpf_attr __user *uattr)
1849{
1850	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1851						  false, true);
1852}
1853
1854static int
1855htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1856		      union bpf_attr __user *uattr)
1857{
1858	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1859						  false, false);
1860}
1861
1862static int
1863htab_map_lookup_and_delete_batch(struct bpf_map *map,
1864				 const union bpf_attr *attr,
1865				 union bpf_attr __user *uattr)
1866{
1867	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1868						  false, false);
1869}
1870
1871static int
1872htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
1873				 const union bpf_attr *attr,
1874				 union bpf_attr __user *uattr)
1875{
1876	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1877						  true, true);
1878}
1879
1880static int
1881htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
1882					    const union bpf_attr *attr,
1883					    union bpf_attr __user *uattr)
1884{
1885	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1886						  true, true);
1887}
1888
1889static int
1890htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
1891			  union bpf_attr __user *uattr)
1892{
1893	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
1894						  true, false);
1895}
1896
1897static int
1898htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
1899				     const union bpf_attr *attr,
1900				     union bpf_attr __user *uattr)
1901{
1902	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
1903						  true, false);
1904}
1905
1906struct bpf_iter_seq_hash_map_info {
1907	struct bpf_map *map;
1908	struct bpf_htab *htab;
1909	void *percpu_value_buf; // non-zero means percpu hash
1910	u32 bucket_id;
1911	u32 skip_elems;
1912};
1913
1914static struct htab_elem *
1915bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
1916			   struct htab_elem *prev_elem)
1917{
1918	const struct bpf_htab *htab = info->htab;
1919	u32 skip_elems = info->skip_elems;
1920	u32 bucket_id = info->bucket_id;
1921	struct hlist_nulls_head *head;
1922	struct hlist_nulls_node *n;
1923	struct htab_elem *elem;
1924	struct bucket *b;
1925	u32 i, count;
1926
1927	if (bucket_id >= htab->n_buckets)
1928		return NULL;
1929
1930	/* try to find next elem in the same bucket */
1931	if (prev_elem) {
1932		/* no update/deletion on this bucket, prev_elem should be still valid
1933		 * and we won't skip elements.
1934		 */
1935		n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
1936		elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
1937		if (elem)
1938			return elem;
1939
1940		/* not found, unlock and go to the next bucket */
1941		b = &htab->buckets[bucket_id++];
1942		rcu_read_unlock();
1943		skip_elems = 0;
1944	}
1945
1946	for (i = bucket_id; i < htab->n_buckets; i++) {
1947		b = &htab->buckets[i];
1948		rcu_read_lock();
1949
1950		count = 0;
1951		head = &b->head;
1952		hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
1953			if (count >= skip_elems) {
1954				info->bucket_id = i;
1955				info->skip_elems = count;
1956				return elem;
1957			}
1958			count++;
1959		}
1960
1961		rcu_read_unlock();
1962		skip_elems = 0;
1963	}
1964
1965	info->bucket_id = i;
1966	info->skip_elems = 0;
1967	return NULL;
1968}
1969
1970static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
1971{
1972	struct bpf_iter_seq_hash_map_info *info = seq->private;
1973	struct htab_elem *elem;
1974
1975	elem = bpf_hash_map_seq_find_next(info, NULL);
1976	if (!elem)
1977		return NULL;
1978
1979	if (*pos == 0)
1980		++*pos;
1981	return elem;
1982}
1983
1984static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1985{
1986	struct bpf_iter_seq_hash_map_info *info = seq->private;
1987
1988	++*pos;
1989	++info->skip_elems;
1990	return bpf_hash_map_seq_find_next(info, v);
1991}
1992
1993static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
1994{
1995	struct bpf_iter_seq_hash_map_info *info = seq->private;
1996	u32 roundup_key_size, roundup_value_size;
1997	struct bpf_iter__bpf_map_elem ctx = {};
1998	struct bpf_map *map = info->map;
1999	struct bpf_iter_meta meta;
2000	int ret = 0, off = 0, cpu;
2001	struct bpf_prog *prog;
2002	void __percpu *pptr;
2003
2004	meta.seq = seq;
2005	prog = bpf_iter_get_info(&meta, elem == NULL);
2006	if (prog) {
2007		ctx.meta = &meta;
2008		ctx.map = info->map;
2009		if (elem) {
2010			roundup_key_size = round_up(map->key_size, 8);
2011			ctx.key = elem->key;
2012			if (!info->percpu_value_buf) {
2013				ctx.value = elem->key + roundup_key_size;
2014			} else {
2015				roundup_value_size = round_up(map->value_size, 8);
2016				pptr = htab_elem_get_ptr(elem, map->key_size);
2017				for_each_possible_cpu(cpu) {
2018					bpf_long_memcpy(info->percpu_value_buf + off,
2019							per_cpu_ptr(pptr, cpu),
2020							roundup_value_size);
2021					off += roundup_value_size;
2022				}
2023				ctx.value = info->percpu_value_buf;
2024			}
2025		}
2026		ret = bpf_iter_run_prog(prog, &ctx);
2027	}
2028
2029	return ret;
2030}
2031
2032static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
2033{
2034	return __bpf_hash_map_seq_show(seq, v);
2035}
2036
2037static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
2038{
2039	if (!v)
2040		(void)__bpf_hash_map_seq_show(seq, NULL);
2041	else
2042		rcu_read_unlock();
2043}
2044
2045static int bpf_iter_init_hash_map(void *priv_data,
2046				  struct bpf_iter_aux_info *aux)
2047{
2048	struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
2049	struct bpf_map *map = aux->map;
2050	void *value_buf;
2051	u32 buf_size;
2052
2053	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
2054	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
2055		buf_size = round_up(map->value_size, 8) * num_possible_cpus();
2056		value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
2057		if (!value_buf)
2058			return -ENOMEM;
2059
2060		seq_info->percpu_value_buf = value_buf;
2061	}
2062
2063	bpf_map_inc_with_uref(map);
2064	seq_info->map = map;
2065	seq_info->htab = container_of(map, struct bpf_htab, map);
2066	return 0;
2067}
2068
2069static void bpf_iter_fini_hash_map(void *priv_data)
2070{
2071	struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
2072
2073	bpf_map_put_with_uref(seq_info->map);
2074	kfree(seq_info->percpu_value_buf);
2075}
2076
2077static const struct seq_operations bpf_hash_map_seq_ops = {
2078	.start	= bpf_hash_map_seq_start,
2079	.next	= bpf_hash_map_seq_next,
2080	.stop	= bpf_hash_map_seq_stop,
2081	.show	= bpf_hash_map_seq_show,
2082};
2083
2084static const struct bpf_iter_seq_info iter_seq_info = {
2085	.seq_ops		= &bpf_hash_map_seq_ops,
2086	.init_seq_private	= bpf_iter_init_hash_map,
2087	.fini_seq_private	= bpf_iter_fini_hash_map,
2088	.seq_priv_size		= sizeof(struct bpf_iter_seq_hash_map_info),
2089};
2090
2091static int bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn,
2092				  void *callback_ctx, u64 flags)
2093{
2094	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2095	struct hlist_nulls_head *head;
2096	struct hlist_nulls_node *n;
2097	struct htab_elem *elem;
2098	u32 roundup_key_size;
2099	int i, num_elems = 0;
2100	void __percpu *pptr;
2101	struct bucket *b;
2102	void *key, *val;
2103	bool is_percpu;
2104	u64 ret = 0;
2105
2106	if (flags != 0)
2107		return -EINVAL;
2108
2109	is_percpu = htab_is_percpu(htab);
2110
2111	roundup_key_size = round_up(map->key_size, 8);
2112	/* disable migration so percpu value prepared here will be the
2113	 * same as the one seen by the bpf program with bpf_map_lookup_elem().
2114	 */
2115	if (is_percpu)
2116		migrate_disable();
2117	for (i = 0; i < htab->n_buckets; i++) {
2118		b = &htab->buckets[i];
2119		rcu_read_lock();
2120		head = &b->head;
2121		hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
2122			key = elem->key;
2123			if (is_percpu) {
2124				/* current cpu value for percpu map */
2125				pptr = htab_elem_get_ptr(elem, map->key_size);
2126				val = this_cpu_ptr(pptr);
2127			} else {
2128				val = elem->key + roundup_key_size;
2129			}
2130			num_elems++;
2131			ret = callback_fn((u64)(long)map, (u64)(long)key,
2132					  (u64)(long)val, (u64)(long)callback_ctx, 0);
2133			/* return value: 0 - continue, 1 - stop and return */
2134			if (ret) {
2135				rcu_read_unlock();
2136				goto out;
2137			}
2138		}
2139		rcu_read_unlock();
2140	}
2141out:
2142	if (is_percpu)
2143		migrate_enable();
2144	return num_elems;
2145}
2146
2147BTF_ID_LIST_SINGLE(htab_map_btf_ids, struct, bpf_htab)
2148const struct bpf_map_ops htab_map_ops = {
2149	.map_meta_equal = bpf_map_meta_equal,
2150	.map_alloc_check = htab_map_alloc_check,
2151	.map_alloc = htab_map_alloc,
2152	.map_free = htab_map_free,
2153	.map_get_next_key = htab_map_get_next_key,
2154	.map_release_uref = htab_map_free_timers,
2155	.map_lookup_elem = htab_map_lookup_elem,
2156	.map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
2157	.map_update_elem = htab_map_update_elem,
2158	.map_delete_elem = htab_map_delete_elem,
2159	.map_gen_lookup = htab_map_gen_lookup,
2160	.map_seq_show_elem = htab_map_seq_show_elem,
2161	.map_set_for_each_callback_args = map_set_for_each_callback_args,
2162	.map_for_each_callback = bpf_for_each_hash_elem,
2163	BATCH_OPS(htab),
2164	.map_btf_id = &htab_map_btf_ids[0],
2165	.iter_seq_info = &iter_seq_info,
2166};
2167
2168const struct bpf_map_ops htab_lru_map_ops = {
2169	.map_meta_equal = bpf_map_meta_equal,
2170	.map_alloc_check = htab_map_alloc_check,
2171	.map_alloc = htab_map_alloc,
2172	.map_free = htab_map_free,
2173	.map_get_next_key = htab_map_get_next_key,
2174	.map_release_uref = htab_map_free_timers,
2175	.map_lookup_elem = htab_lru_map_lookup_elem,
2176	.map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
2177	.map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
2178	.map_update_elem = htab_lru_map_update_elem,
2179	.map_delete_elem = htab_lru_map_delete_elem,
2180	.map_gen_lookup = htab_lru_map_gen_lookup,
2181	.map_seq_show_elem = htab_map_seq_show_elem,
2182	.map_set_for_each_callback_args = map_set_for_each_callback_args,
2183	.map_for_each_callback = bpf_for_each_hash_elem,
2184	BATCH_OPS(htab_lru),
2185	.map_btf_id = &htab_map_btf_ids[0],
2186	.iter_seq_info = &iter_seq_info,
2187};
2188
2189/* Called from eBPF program */
2190static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2191{
2192	struct htab_elem *l = __htab_map_lookup_elem(map, key);
2193
2194	if (l)
2195		return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2196	else
2197		return NULL;
2198}
2199
2200static void *htab_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
2201{
2202	struct htab_elem *l;
2203
2204	if (cpu >= nr_cpu_ids)
2205		return NULL;
2206
2207	l = __htab_map_lookup_elem(map, key);
2208	if (l)
2209		return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
2210	else
2211		return NULL;
2212}
2213
2214static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
2215{
2216	struct htab_elem *l = __htab_map_lookup_elem(map, key);
2217
2218	if (l) {
2219		bpf_lru_node_set_ref(&l->lru_node);
2220		return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
2221	}
2222
2223	return NULL;
2224}
2225
2226static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
2227{
2228	struct htab_elem *l;
2229
2230	if (cpu >= nr_cpu_ids)
2231		return NULL;
2232
2233	l = __htab_map_lookup_elem(map, key);
2234	if (l) {
2235		bpf_lru_node_set_ref(&l->lru_node);
2236		return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
2237	}
2238
2239	return NULL;
2240}
2241
2242int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
2243{
2244	struct htab_elem *l;
2245	void __percpu *pptr;
2246	int ret = -ENOENT;
2247	int cpu, off = 0;
2248	u32 size;
2249
2250	/* per_cpu areas are zero-filled and bpf programs can only
2251	 * access 'value_size' of them, so copying rounded areas
2252	 * will not leak any kernel data
2253	 */
2254	size = round_up(map->value_size, 8);
2255	rcu_read_lock();
2256	l = __htab_map_lookup_elem(map, key);
2257	if (!l)
2258		goto out;
2259	/* We do not mark LRU map element here in order to not mess up
2260	 * eviction heuristics when user space does a map walk.
2261	 */
2262	pptr = htab_elem_get_ptr(l, map->key_size);
2263	for_each_possible_cpu(cpu) {
2264		bpf_long_memcpy(value + off,
2265				per_cpu_ptr(pptr, cpu), size);
2266		off += size;
2267	}
2268	ret = 0;
2269out:
2270	rcu_read_unlock();
2271	return ret;
2272}
2273
2274int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
2275			   u64 map_flags)
2276{
2277	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2278	int ret;
2279
2280	rcu_read_lock();
2281	if (htab_is_lru(htab))
2282		ret = __htab_lru_percpu_map_update_elem(map, key, value,
2283							map_flags, true);
2284	else
2285		ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
2286						    true);
2287	rcu_read_unlock();
2288
2289	return ret;
2290}
2291
2292static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
2293					  struct seq_file *m)
2294{
2295	struct htab_elem *l;
2296	void __percpu *pptr;
2297	int cpu;
2298
2299	rcu_read_lock();
2300
2301	l = __htab_map_lookup_elem(map, key);
2302	if (!l) {
2303		rcu_read_unlock();
2304		return;
2305	}
2306
2307	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
2308	seq_puts(m, ": {\n");
2309	pptr = htab_elem_get_ptr(l, map->key_size);
2310	for_each_possible_cpu(cpu) {
2311		seq_printf(m, "\tcpu%d: ", cpu);
2312		btf_type_seq_show(map->btf, map->btf_value_type_id,
2313				  per_cpu_ptr(pptr, cpu), m);
2314		seq_puts(m, "\n");
2315	}
2316	seq_puts(m, "}\n");
2317
2318	rcu_read_unlock();
2319}
2320
2321const struct bpf_map_ops htab_percpu_map_ops = {
2322	.map_meta_equal = bpf_map_meta_equal,
2323	.map_alloc_check = htab_map_alloc_check,
2324	.map_alloc = htab_map_alloc,
2325	.map_free = htab_map_free,
2326	.map_get_next_key = htab_map_get_next_key,
2327	.map_lookup_elem = htab_percpu_map_lookup_elem,
2328	.map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
2329	.map_update_elem = htab_percpu_map_update_elem,
2330	.map_delete_elem = htab_map_delete_elem,
2331	.map_lookup_percpu_elem = htab_percpu_map_lookup_percpu_elem,
2332	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
2333	.map_set_for_each_callback_args = map_set_for_each_callback_args,
2334	.map_for_each_callback = bpf_for_each_hash_elem,
2335	BATCH_OPS(htab_percpu),
2336	.map_btf_id = &htab_map_btf_ids[0],
2337	.iter_seq_info = &iter_seq_info,
2338};
2339
2340const struct bpf_map_ops htab_lru_percpu_map_ops = {
2341	.map_meta_equal = bpf_map_meta_equal,
2342	.map_alloc_check = htab_map_alloc_check,
2343	.map_alloc = htab_map_alloc,
2344	.map_free = htab_map_free,
2345	.map_get_next_key = htab_map_get_next_key,
2346	.map_lookup_elem = htab_lru_percpu_map_lookup_elem,
2347	.map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
2348	.map_update_elem = htab_lru_percpu_map_update_elem,
2349	.map_delete_elem = htab_lru_map_delete_elem,
2350	.map_lookup_percpu_elem = htab_lru_percpu_map_lookup_percpu_elem,
2351	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
2352	.map_set_for_each_callback_args = map_set_for_each_callback_args,
2353	.map_for_each_callback = bpf_for_each_hash_elem,
2354	BATCH_OPS(htab_lru_percpu),
2355	.map_btf_id = &htab_map_btf_ids[0],
2356	.iter_seq_info = &iter_seq_info,
2357};
2358
2359static int fd_htab_map_alloc_check(union bpf_attr *attr)
2360{
2361	if (attr->value_size != sizeof(u32))
2362		return -EINVAL;
2363	return htab_map_alloc_check(attr);
2364}
2365
2366static void fd_htab_map_free(struct bpf_map *map)
2367{
2368	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
2369	struct hlist_nulls_node *n;
2370	struct hlist_nulls_head *head;
2371	struct htab_elem *l;
2372	int i;
2373
2374	for (i = 0; i < htab->n_buckets; i++) {
2375		head = select_bucket(htab, i);
2376
2377		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
2378			void *ptr = fd_htab_map_get_ptr(map, l);
2379
2380			map->ops->map_fd_put_ptr(ptr);
2381		}
2382	}
2383
2384	htab_map_free(map);
2385}
2386
2387/* only called from syscall */
2388int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
2389{
2390	void **ptr;
2391	int ret = 0;
2392
2393	if (!map->ops->map_fd_sys_lookup_elem)
2394		return -ENOTSUPP;
2395
2396	rcu_read_lock();
2397	ptr = htab_map_lookup_elem(map, key);
2398	if (ptr)
2399		*value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
2400	else
2401		ret = -ENOENT;
2402	rcu_read_unlock();
2403
2404	return ret;
2405}
2406
2407/* only called from syscall */
2408int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
2409				void *key, void *value, u64 map_flags)
2410{
2411	void *ptr;
2412	int ret;
2413	u32 ufd = *(u32 *)value;
2414
2415	ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
2416	if (IS_ERR(ptr))
2417		return PTR_ERR(ptr);
2418
2419	ret = htab_map_update_elem(map, key, &ptr, map_flags);
2420	if (ret)
2421		map->ops->map_fd_put_ptr(ptr);
2422
2423	return ret;
2424}
2425
2426static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
2427{
2428	struct bpf_map *map, *inner_map_meta;
2429
2430	inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
2431	if (IS_ERR(inner_map_meta))
2432		return inner_map_meta;
2433
2434	map = htab_map_alloc(attr);
2435	if (IS_ERR(map)) {
2436		bpf_map_meta_free(inner_map_meta);
2437		return map;
2438	}
2439
2440	map->inner_map_meta = inner_map_meta;
2441
2442	return map;
2443}
2444
2445static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
2446{
2447	struct bpf_map **inner_map  = htab_map_lookup_elem(map, key);
2448
2449	if (!inner_map)
2450		return NULL;
2451
2452	return READ_ONCE(*inner_map);
2453}
2454
2455static int htab_of_map_gen_lookup(struct bpf_map *map,
2456				  struct bpf_insn *insn_buf)
2457{
2458	struct bpf_insn *insn = insn_buf;
2459	const int ret = BPF_REG_0;
2460
2461	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
2462		     (void *(*)(struct bpf_map *map, void *key))NULL));
2463	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
2464	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
2465	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
2466				offsetof(struct htab_elem, key) +
2467				round_up(map->key_size, 8));
2468	*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
2469
2470	return insn - insn_buf;
2471}
2472
2473static void htab_of_map_free(struct bpf_map *map)
2474{
2475	bpf_map_meta_free(map->inner_map_meta);
2476	fd_htab_map_free(map);
2477}
2478
2479const struct bpf_map_ops htab_of_maps_map_ops = {
2480	.map_alloc_check = fd_htab_map_alloc_check,
2481	.map_alloc = htab_of_map_alloc,
2482	.map_free = htab_of_map_free,
2483	.map_get_next_key = htab_map_get_next_key,
2484	.map_lookup_elem = htab_of_map_lookup_elem,
2485	.map_delete_elem = htab_map_delete_elem,
2486	.map_fd_get_ptr = bpf_map_fd_get_ptr,
2487	.map_fd_put_ptr = bpf_map_fd_put_ptr,
2488	.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
2489	.map_gen_lookup = htab_of_map_gen_lookup,
2490	.map_check_btf = map_check_no_btf,
2491	BATCH_OPS(htab),
2492	.map_btf_id = &htab_map_btf_ids[0],
2493};
2494