bcachefs: Optimize bch2_btree_iter_verify_level()

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -492,9 +492,9 @@ static void bch2_btree_iter_verify_cached(struct btree_iter *iter)
 static void bch2_btree_iter_verify_level(struct btree_iter *iter,
 					 unsigned level)
 {
-	struct btree_iter_level *l = &iter->l[level];
-	struct btree_node_iter tmp = l->iter;
-	bool locked = btree_node_locked(iter, level);
+	struct btree_iter_level *l;
+	struct btree_node_iter tmp;
+	bool locked;
 	struct bkey_packed *p, *k;
 	char buf1[100], buf2[100], buf3[100];
 	const char *msg;
@@ -502,6 +502,10 @@ static void bch2_btree_iter_verify_level(struct btree_iter *iter,
 	if (!bch2_debug_check_iterators)
 		return;
 
+	l	= &iter->l[level];
+	tmp	= l->iter;
+	locked	= btree_node_locked(iter, level);
+
 	if (btree_iter_type(iter) == BTREE_ITER_CACHED) {
 		if (!level)
 			bch2_btree_iter_verify_cached(iter);