Commit add1f099 authored Feb 12, 2014 by Paul E. McKenney

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>

parent ae167033

fs/file.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -497,7 +497,7 @@ int __alloc_fd(struct files_struct *files,
		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);
		}