dentries: Extract common code to remove dentry from lru

Extract the common code to remove a dentry from the lru into a new function
dentry_lru_remove().

Two call sites used list_del() instead of list_del_init().  AFAIK the
performance of both is the same.  dentry_lru_remove() does a list_del_init().

As a result dentry->d_lru is now always empty when a dentry is freed.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/dcache.c b/fs/dcache.c
index 7b4b080219f8e2238b8de00ff5351b72b2bf722a..43455776711e176a449f42282f99a444c3a88c35 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -95,6 +95,14 @@ static void d_free(struct dentry *dentry)
                call_rcu(&dentry->d_u.d_rcu, d_callback);
 }
 
+static void dentry_lru_remove(struct dentry *dentry)
+{
+       if (!list_empty(&dentry->d_lru)) {
+               list_del_init(&dentry->d_lru);
+               dentry_stat.nr_unused--;
+       }
+}
+
 /*
  * Release the dentry's inode, using the filesystem
  * d_iput() operation if defined.
@@ -211,13 +219,7 @@ repeat:
 unhash_it:
        __d_drop(dentry);
 kill_it:
-       /* If dentry was on d_lru list
-        * delete it from there
-        */
-       if (!list_empty(&dentry->d_lru)) {
-               list_del(&dentry->d_lru);
-               dentry_stat.nr_unused--;
-       }
+       dentry_lru_remove(dentry);
        dentry = d_kill(dentry);
        if (dentry)
                goto repeat;
@@ -285,10 +287,7 @@ int d_invalidate(struct dentry * dentry)
 static inline struct dentry * __dget_locked(struct dentry *dentry)
 {
        atomic_inc(&dentry->d_count);
-       if (!list_empty(&dentry->d_lru)) {
-               dentry_stat.nr_unused--;
-               list_del_init(&dentry->d_lru);
-       }
+       dentry_lru_remove(dentry);
        return dentry;
 }
 
@@ -404,10 +403,7 @@ static void prune_one_dentry(struct dentry * dentry)
 
                if (dentry->d_op && dentry->d_op->d_delete)
                        dentry->d_op->d_delete(dentry);
-               if (!list_empty(&dentry->d_lru)) {
-                       list_del(&dentry->d_lru);
-                       dentry_stat.nr_unused--;
-               }
+               dentry_lru_remove(dentry);
                __d_drop(dentry);
                dentry = d_kill(dentry);
                spin_lock(&dcache_lock);
@@ -596,10 +592,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 
        /* detach this root from the system */
        spin_lock(&dcache_lock);
-       if (!list_empty(&dentry->d_lru)) {
-               dentry_stat.nr_unused--;
-               list_del_init(&dentry->d_lru);
-       }
+       dentry_lru_remove(dentry);
        __d_drop(dentry);
        spin_unlock(&dcache_lock);
 
@@ -613,11 +606,7 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
                        spin_lock(&dcache_lock);
                        list_for_each_entry(loop, &dentry->d_subdirs,
                                            d_u.d_child) {
-                               if (!list_empty(&loop->d_lru)) {
-                                       dentry_stat.nr_unused--;
-                                       list_del_init(&loop->d_lru);
-                               }
-
+                               dentry_lru_remove(loop);
                                __d_drop(loop);
                                cond_resched_lock(&dcache_lock);
                        }
@@ -799,10 +788,7 @@ resume:
                struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
                next = tmp->next;
 
-               if (!list_empty(&dentry->d_lru)) {
-                       dentry_stat.nr_unused--;
-                       list_del_init(&dentry->d_lru);
-               }
+               dentry_lru_remove(dentry);
                /* 
                 * move only zero ref count dentries to the end 
                 * of the unused list for prune_dcache