From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Wed, 12 Feb 2014 20:51:09 +0000 (-0800)
Subject: fs: Substitute rcu_access_pointer() for rcu_dereference_raw()
X-Git-Tag: next-20140306~34^2~19^2^2~1^2~3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=add1f0995454374d90c9d6b2c420d2fba3d0a4e3;p=karo-tx-linux.git

fs: Substitute rcu_access_pointer() for rcu_dereference_raw()

(Trivial patch.)

If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded to
rcu_access_pointer().  This commit makes this downgrade in __alloc_fd(),
which simply compares the RCU-protected pointer against NULL with no
dereferencing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---

diff --git a/fs/file.c b/fs/file.c
index db25c2bdfe46..18f7d27855c4 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -497,7 +497,7 @@ repeat:
 	error = fd;
 #if 1
 	/* Sanity check */
-	if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
+	if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
 		printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
 		rcu_assign_pointer(fdt->fd[fd], NULL);
 	}