rculist: use list_entry_rcu in places where it's appropriate

Use previously introduced list_entry_rcu instead of an open-coded
list_entry + rcu_dereference combination.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: dipankar@in.ibm.com
LKML-Reference: <20090414181715.GA3634@psychotron.englab.brq.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/ipc/sem.c b/ipc/sem.c
index 16a2189..87c2b64 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1290,8 +1290,8 @@
 		int i;
 
 		rcu_read_lock();
-		un = list_entry(rcu_dereference(ulp->list_proc.next),
-					struct sem_undo, list_proc);
+		un = list_entry_rcu(ulp->list_proc.next,
+				    struct sem_undo, list_proc);
 		if (&un->list_proc == &ulp->list_proc)
 			semid = -1;
 		 else