NFSv4.2: xattr cache: get rid of cache discard work queue

Caches should be small enough to discard them inline, so do that
instead of using a work queue.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
index 23fdab9..8677799 100644 (file)
--- a/fs/nfs/nfs42xattr.c
+++ b/fs/nfs/nfs42xattr.c
@@ -75,7 +75,6 @@ struct nfs4_xattr_cache {
        spinlock_t listxattr_lock;
        struct inode *inode;
        struct nfs4_xattr_entry *listxattr;
-       struct work_struct work;
 };
 
 struct nfs4_xattr_entry {
@@ -101,8 +100,6 @@ static struct list_lru nfs4_xattr_large_entry_lru;
 
 static struct kmem_cache *nfs4_xattr_cache_cachep;
 
-static struct workqueue_struct *nfs4_xattr_cache_wq;
-
 /*
  * Hashing helper functions.
  */
@@ -365,9 +362,8 @@ nfs4_xattr_cache_unlink(struct inode *inode)
 }
 
 /*
- * Discard a cache. Usually called by a worker, since walking all
- * the entries can take up some cycles that we don't want to waste
- * in the I/O path. Can also be called from the shrinker callback.
+ * Discard a cache. Called by get_cache() if there was an old,
+ * invalid cache. Can also be called from a shrinker callback.
  *
  * The cache is dead, it has already been unlinked from its inode,
  * and no longer appears on the cache LRU list.
@@ -414,21 +410,6 @@ nfs4_xattr_discard_cache(struct nfs4_xattr_cache *cache)
        kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
 }
 
-static void
-nfs4_xattr_discard_cache_worker(struct work_struct *work)
-{
-       struct nfs4_xattr_cache *cache = container_of(work,
-           struct nfs4_xattr_cache, work);
-
-       nfs4_xattr_discard_cache(cache);
-}
-
-static void
-nfs4_xattr_reap_cache(struct nfs4_xattr_cache *cache)
-{
-       queue_work(nfs4_xattr_cache_wq, &cache->work);
-}
-
 /*
  * Get a referenced copy of the cache structure. Avoid doing allocs
  * while holding i_lock. Which means that we do some optimistic allocation,
@@ -513,10 +494,10 @@ nfs4_xattr_get_cache(struct inode *inode, int add)
 
 out:
        /*
-        * Discarding an old cache is done via a workqueue.
+        * Discard the now orphaned old cache.
         */
        if (oldcache != NULL)
-               nfs4_xattr_reap_cache(oldcache);
+               nfs4_xattr_discard_cache(oldcache);
 
        return cache;
 }
@@ -1008,7 +989,6 @@ static void nfs4_xattr_cache_init_once(void *p)
        atomic_long_set(&cache->nent, 0);
        nfs4_xattr_hash_init(cache);
        cache->listxattr = NULL;
-       INIT_WORK(&cache->work, nfs4_xattr_discard_cache_worker);
        INIT_LIST_HEAD(&cache->lru);
        INIT_LIST_HEAD(&cache->dispose);
 }
@@ -1039,13 +1019,9 @@ int __init nfs4_xattr_cache_init(void)
        if (ret)
                goto out2;
 
-       nfs4_xattr_cache_wq = alloc_workqueue("nfs4_xattr", WQ_MEM_RECLAIM, 0);
-       if (nfs4_xattr_cache_wq == NULL)
-               goto out1;
-
        ret = register_shrinker(&nfs4_xattr_cache_shrinker);
        if (ret)
-               goto out0;
+               goto out1;
 
        ret = register_shrinker(&nfs4_xattr_entry_shrinker);
        if (ret)
@@ -1058,8 +1034,6 @@ int __init nfs4_xattr_cache_init(void)
        unregister_shrinker(&nfs4_xattr_entry_shrinker);
 out:
        unregister_shrinker(&nfs4_xattr_cache_shrinker);
-out0:
-       destroy_workqueue(nfs4_xattr_cache_wq);
 out1:
        list_lru_destroy(&nfs4_xattr_cache_lru);
 out2:
@@ -1079,5 +1053,4 @@ void nfs4_xattr_cache_exit(void)
        list_lru_destroy(&nfs4_xattr_entry_lru);
        list_lru_destroy(&nfs4_xattr_cache_lru);
        kmem_cache_destroy(nfs4_xattr_cache_cachep);
-       destroy_workqueue(nfs4_xattr_cache_wq);
 }