diff options
Diffstat (limited to 'fs/mbcache.c')
| -rw-r--r-- | fs/mbcache.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/fs/mbcache.c b/fs/mbcache.c index 47ccfcbe0a22..e272ad738faf 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -90,8 +90,14 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, return -ENOMEM; INIT_LIST_HEAD(&entry->e_list); - /* Initial hash reference */ - atomic_set(&entry->e_refcnt, 1); + /* + * We create entry with two references. One reference is kept by the + * hash table, the other reference is used to protect us from + * mb_cache_entry_delete_or_get() until the entry is fully setup. This + * avoids nesting of cache->c_list_lock into hash table bit locks which + * is problematic for RT. + */ + atomic_set(&entry->e_refcnt, 2); entry->e_key = key; entry->e_value = value; entry->e_reusable = reusable; @@ -106,15 +112,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, } } hlist_bl_add_head(&entry->e_hash_list, head); - /* - * Add entry to LRU list before it can be found by - * mb_cache_entry_delete() to avoid races - */ + hlist_bl_unlock(head); spin_lock(&cache->c_list_lock); list_add_tail(&entry->e_list, &cache->c_list); cache->c_entry_count++; spin_unlock(&cache->c_list_lock); - hlist_bl_unlock(head); + mb_cache_entry_put(cache, entry); return 0; } |