ocfs2: use list_for_each_entry() instead of list_for_each()

[dan.carpenter@oracle.com: fix up some NULL dereference bugs]
Signed-off-by: Dong Fang <yp.fangdong@gmail.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jeff Liu <jeff.liu@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 5c1c864..25b72e8 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -628,11 +628,9 @@
 				struct o2nm_node *node,
 				int idx)
 {
-	struct list_head *iter;
 	struct o2hb_callback_func *f;
 
-	list_for_each(iter, &hbcall->list) {
-		f = list_entry(iter, struct o2hb_callback_func, hc_item);
+	list_for_each_entry(f, &hbcall->list, hc_item) {
 		mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 		(f->hc_func)(node, idx, f->hc_data);
 	}
@@ -2516,8 +2514,7 @@
 int o2hb_register_callback(const char *region_uuid,
 			   struct o2hb_callback_func *hc)
 {
-	struct o2hb_callback_func *tmp;
-	struct list_head *iter;
+	struct o2hb_callback_func *f;
 	struct o2hb_callback *hbcall;
 	int ret;
 
@@ -2540,10 +2537,9 @@
 
 	down_write(&o2hb_callback_sem);
 
-	list_for_each(iter, &hbcall->list) {
-		tmp = list_entry(iter, struct o2hb_callback_func, hc_item);
-		if (hc->hc_priority < tmp->hc_priority) {
-			list_add_tail(&hc->hc_item, iter);
+	list_for_each_entry(f, &hbcall->list, hc_item) {
+		if (hc->hc_priority < f->hc_priority) {
+			list_add_tail(&hc->hc_item, &f->hc_item);
 			break;
 		}
 	}