fs: inode.c use atomic_inc_return in __iget

Using atomic_inc_return in __iget(struct inode *inode) makes the intent
of this code clearer and generates less code on processors that have
this operation.

On x86_64 this patch reduces the text size of inode.o by 12 bytes.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
----
patch against 2.6.34-rc7
compiled & tested on x86_64 AMD X2

I've been running with this patch applied for several weeks with no
obvious problems.
regards
Richard
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/inode.c b/fs/inode.c
index 258ec22..498b10f 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -286,11 +286,9 @@ static void init_once(void *foo)
  */
 void __iget(struct inode *inode)
 {
-       if (atomic_read(&inode->i_count)) {
-               atomic_inc(&inode->i_count);
+       if (atomic_inc_return(&inode->i_count) != 1)
                return;
-       }
-       atomic_inc(&inode->i_count);
+
        if (!(inode->i_state & (I_DIRTY|I_SYNC)))
                list_move(&inode->i_list, &inode_in_use);
        inodes_stat.nr_unused--;