X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=block%2Fblk-sysfs.c;h=b78c9c3e26705f45fb1e90ac116dc8bb96c8122b;hb=28f9f19db9dda54c851d5689539d86f6fc008773;hp=d3aa2aadb3e0e7d18645a2eb9333698f4984263a;hpb=a3c8b97396ef42edfb845788ba6f53b2a93ce980;p=firefly-linux-kernel-4.4.55.git

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index d3aa2aadb3e0..b78c9c3e2670 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -40,7 +40,12 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
 {
 	struct request_list *rl = &q->rq;
 	unsigned long nr;
-	int ret = queue_var_store(&nr, page, count);
+	int ret;
+
+	if (!q->request_fn)
+		return -EINVAL;
+
+	ret = queue_var_store(&nr, page, count);
 	if (nr < BLKDEV_MIN_RQ)
 		nr = BLKDEV_MIN_RQ;