__d_move(): fold manipulations with ->d_child/->d_subdirs

list_del() + list_add() is a slightly pessimised list_move()
list_del() + INIT_LIST_HEAD() is a slightly pessimised list_del_init()

Interleaving those makes the resulting code even worse.  And harder to follow...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/dcache.c b/fs/dcache.c
index 22107630fc031be1438f3039c3f81e1986fbcd1d..86afdf1376ac1c3e99f76ec6744b619faf594708 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2506,8 +2506,6 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
                           d_hash(dentry->d_parent, dentry->d_name.hash));
        }
 
-       list_del(&dentry->d_u.d_child);
-       list_del(&target->d_u.d_child);
 
        /* Switch the names.. */
        switch_names(dentry, target);
@@ -2517,15 +2515,15 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
        if (IS_ROOT(dentry)) {
                dentry->d_parent = target->d_parent;
                target->d_parent = target;
-               INIT_LIST_HEAD(&target->d_u.d_child);
+               list_del_init(&target->d_u.d_child);
        } else {
                swap(dentry->d_parent, target->d_parent);
 
                /* And add them back to the (new) parent lists */
-               list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
+               list_move(&target->d_u.d_child, &target->d_parent->d_subdirs);
        }
 
-       list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
+       list_move(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
 
        write_seqcount_end(&target->d_seq);
        write_seqcount_end(&dentry->d_seq);