virtio_net: fix return value check in receive_mergeable()

[ Upstream commit 03e9f8a05bce7330bcd9c5cc54c8e42d0fcbf993 ]

The function virtqueue_get_buf_ctx() could return NULL, the return
value 'buf' need to be checked with NULL, not value 'ctx'.

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 511f833..7927e28 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -714,7 +714,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                int num_skb_frags;
 
                buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx);
-               if (unlikely(!ctx)) {
+               if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers out of %d missing\n",
                                 dev->name, num_buf,
                                 virtio16_to_cpu(vi->vdev,