ocfs2: remove usage of list iterator variable after the loop body

To move the list iterator variable into the list_for_each_entry_*() macro
in the future it should be avoided to use the list iterator variable after
the loop body.

To *never* use the list iterator variable after the loop it was concluded
to use a separate iterator variable [1].

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20220322105014.3626194-1-jakobkoschel@gmail.com
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/dlm/dlmdebug.c

@@ -541,7 +541,7 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
 	struct debug_lockres *dl = m->private;
 	struct dlm_ctxt *dlm = dl->dl_ctxt;
 	struct dlm_lock_resource *oldres = dl->dl_res;
-	struct dlm_lock_resource *res = NULL;
+	struct dlm_lock_resource *res = NULL, *iter;
 	struct list_head *track_list;
 
 	spin_lock(&dlm->track_lock);
@@ -556,11 +556,11 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
 		}
 	}
 
-	list_for_each_entry(res, track_list, tracking) {
-		if (&res->tracking == &dlm->tracking_list)
-			res = NULL;
-		else
-			dlm_lockres_get(res);
+	list_for_each_entry(iter, track_list, tracking) {
+		if (&iter->tracking != &dlm->tracking_list) {
+			dlm_lockres_get(iter);
+			res = iter;
+		}
 		break;
 	}
 	spin_unlock(&dlm->track_lock);