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>

1 files changed, 14 insertions, 28 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 7b4b080219f8..43455776711e 100644
--- 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