[PATCH net] virtio-net: correctly enable callback during start_xmit

[Jason Wang]

Commit a7766ef18b33("virtio_net: disable cb aggressively") enables
virtqueue callback via the following statement:

        do {
           ......
	} while (use_napi && kick &&
               unlikely(!virtqueue_enable_cb_delayed(sq->vq)));

This will cause a missing call to virtqueue_enable_cb_delayed() when
kick is false. Fixing this by removing the checking of the kick from
the condition to make sure callback is enabled correctly.

Fixes: a7766ef18b33 ("virtio_net: disable cb aggressively")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
The patch is needed for -stable.
---
 drivers/net/virtio_net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 86e52454b5b5..44d7daf0267b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1834,8 +1834,8 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 		free_old_xmit_skbs(sq, false);
 
-	} while (use_napi && kick &&
-	       unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
+	} while (use_napi &&
+		 unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
 
 	/* timestamp packet in software */
 	skb_tx_timestamp(skb);
-- 
2.25.1