[PATCH net V2] xen-netback: don't move event pointer in TX credit timeout callback

... otherwise the frontend will try to send TX event all the time, even
if no progress can be made. The pointer should only be advanced by the
routine that actually processes the ring (that is, xenvif_poll).

Reported-by: Jacek Konieczny <redacted>
Signed-off-by: Wei Liu <redacted>
Acked-by: Ian Campbell <redacted>
Cc: Paul Durrant <redacted>
---
 drivers/net/xen-netback/netback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 7666540..8e2cbeb 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c

@@ -658,7 +658,7 @@ void xenvif_check_rx_xenvif(struct xenvif *vif)
 {
 	int more_to_do;
 
-	RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
+	more_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx);
 
 	if (more_to_do)
 		napi_schedule(&vif->napi);

-- 
1.7.10.4