io_uring/alloc_cache.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef IOU_ALLOC_CACHE_H
   3 #define IOU_ALLOC_CACHE_H
   4
   5 #include <linux/io_uring_types.h>
   6 #include <linux/kasan.h>
   7
   8 /*
   9  * Don't allow the cache to grow beyond this size.
  10  */
  11 #define IO_ALLOC_CACHE_MAX      128
  12
  13 void io_alloc_cache_free(struct io_alloc_cache *cache,
  14                          void (*free)(const void *));
  15 bool io_alloc_cache_init(struct io_alloc_cache *cache,
  16                          unsigned max_nr, unsigned int size,
  17                          unsigned int init_bytes);
  18
  19 void *io_cache_alloc_new(struct io_alloc_cache *cache, gfp_t gfp);
  20
  21 static inline bool io_alloc_cache_put(struct io_alloc_cache *cache,
  22                                       void *entry)
  23 {
  24         if (cache->nr_cached < cache->max_cached) {
  25                 if (!kasan_mempool_poison_object(entry))
  26                         return false;
  27                 cache->entries[cache->nr_cached++] = entry;
  28                 return true;
  29         }
  30         return false;
  31 }
  32
  33 static inline void *io_alloc_cache_get(struct io_alloc_cache *cache)
  34 {
  35         if (cache->nr_cached) {
  36                 void *entry = cache->entries[--cache->nr_cached];
  37
  38                 /*
  39                  * If KASAN is enabled, always clear the initial bytes that
  40                  * must be zeroed post alloc, in case any of them overlap
  41                  * with KASAN storage.
  42                  */
  43 #if defined(CONFIG_KASAN)
  44                 kasan_mempool_unpoison_object(entry, cache->elem_size);
  45                 if (cache->init_clear)
  46                         memset(entry, 0, cache->init_clear);
  47 #endif
  48                 return entry;
  49         }
  50
  51         return NULL;
  52 }
  53
  54 static inline void *io_cache_alloc(struct io_alloc_cache *cache, gfp_t gfp)
  55 {
  56         void *obj;
  57
  58         obj = io_alloc_cache_get(cache);
  59         if (obj)
  60                 return obj;
  61         return io_cache_alloc_new(cache, gfp);
  62 }
  63
  64 static inline void io_cache_free(struct io_alloc_cache *cache, void *obj)
  65 {
  66         if (!io_alloc_cache_put(cache, obj))
  67                 kfree(obj);
  68 }
  69
  70 #endif