gfs2: Clean up gfs2_scan_glock_lru

Switch to list_for_each_entry_safe() and eliminate the "skipped" list in
gfs2_scan_glock_lru().

At the same time, scan the requested number of items to scan, not one
more than that number.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -1985,26 +1985,21 @@ __acquires(&lru_lock)
 
 static long gfs2_scan_glock_lru(int nr)
 {
-	struct gfs2_glock *gl;
-	LIST_HEAD(skipped);
+	struct gfs2_glock *gl, *next;
 	LIST_HEAD(dispose);
 	long freed = 0;
 
 	spin_lock(&lru_lock);
-	while ((nr-- >= 0) && !list_empty(&lru_list)) {
-		gl = list_first_entry(&lru_list, struct gfs2_glock, gl_lru);
-
+	list_for_each_entry_safe(gl, next, &lru_list, gl_lru) {
+		if (nr-- <= 0)
+			break;
 		/* Test for being demotable */
 		if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
 			list_move(&gl->gl_lru, &dispose);
 			atomic_dec(&lru_count);
 			freed++;
-			continue;
 		}
-
-		list_move(&gl->gl_lru, &skipped);
 	}
-	list_splice(&skipped, &lru_list);
 	if (!list_empty(&dispose))
 		gfs2_dispose_glock_lru(&dispose);
 	spin_unlock(&lru_lock);