devcgroup: use list_for_each_entry_rcu()

We should use list_for_each_entry_rcu in RCU read site.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

security/device_cgroup.c

@@ -517,7 +517,7 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 
 	dev_cgroup = task_devcgroup(current);
 
-	list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
+	list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
 		if (wh->type & DEV_ALL)
 			goto acc_check;
 		if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))