1#ifndef IOU_ALLOC_CACHE_H
2#define IOU_ALLOC_CACHE_H
3
4/*
5 * Don't allow the cache to grow beyond this size.
6 */
7#define IO_ALLOC_CACHE_MAX 512
8
9struct io_cache_entry {
10 struct io_wq_work_node node;
11};
12
13static inline bool io_alloc_cache_put(struct io_alloc_cache *cache,
14 struct io_cache_entry *entry)
15{
16 if (cache->nr_cached < cache->max_cached) {
17 cache->nr_cached++;
18 wq_stack_add_head(node: &entry->node, stack: &cache->list);
19 /* KASAN poisons object */
20 kasan_slab_free_mempool(ptr: entry);
21 return true;
22 }
23 return false;
24}
25
26static inline bool io_alloc_cache_empty(struct io_alloc_cache *cache)
27{
28 return !cache->list.next;
29}
30
31static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *cache)
32{
33 if (cache->list.next) {
34 struct io_cache_entry *entry;
35
36 entry = container_of(cache->list.next, struct io_cache_entry, node);
37 kasan_unpoison_range(address: entry, size: cache->elem_size);
38 cache->list.next = cache->list.next->next;
39 cache->nr_cached--;
40 return entry;
41 }
42
43 return NULL;
44}
45
46static inline void io_alloc_cache_init(struct io_alloc_cache *cache,
47 unsigned max_nr, size_t size)
48{
49 cache->list.next = NULL;
50 cache->nr_cached = 0;
51 cache->max_cached = max_nr;
52 cache->elem_size = size;
53}
54
55static inline void io_alloc_cache_free(struct io_alloc_cache *cache,
56 void (*free)(struct io_cache_entry *))
57{
58 while (1) {
59 struct io_cache_entry *entry = io_alloc_cache_get(cache);
60
61 if (!entry)
62 break;
63 free(entry);
64 }
65 cache->nr_cached = 0;
66}
67#endif
68

source code of linux/io_uring/alloc_cache.h