edac,rcu: use synchronize_rcu() instead of call_rcu()+rcu_barrier()

synchronize_rcu() does the stuff as needed.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 1d80560..d69144a 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -447,20 +447,16 @@
 	return 1;
 }
 
-static void complete_mc_list_del(struct rcu_head *head)
-{
-	struct mem_ctl_info *mci;
-
-	mci = container_of(head, struct mem_ctl_info, rcu);
-	INIT_LIST_HEAD(&mci->link);
-}
-
 static void del_mc_from_global_list(struct mem_ctl_info *mci)
 {
 	atomic_dec(&edac_handlers);
 	list_del_rcu(&mci->link);
-	call_rcu(&mci->rcu, complete_mc_list_del);
-	rcu_barrier();
+
+	/* these are for safe removal of devices from global list while
+	 * NMI handlers may be traversing list
+	 */
+	synchronize_rcu();
+	INIT_LIST_HEAD(&mci->link);
 }
 
 /**