xen-netback: fix guest Rx stall detection (after guest Rx refactor)

If a VIF has been ready for rx_stall_timeout (60s by default) and an
Rx ring is drained of all requests an Rx stall will be incorrectly
detected.  When this occurs and the guest Rx queue is empty, the Rx
ring's event index will not be set and the frontend will not raise an
event when new requests are placed on the ring, permanently stalling
the VIF.

This is a regression introduced by eb1723a29b9a7 (xen-netback:
refactor guest rx).

Fix this by reinstating the setting of queue->last_rx_time when
placing a packet onto the guest Rx ring.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit d1ef006dc116bf6487426b0b50c1bf2bf51e6423)
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index 395c967ea9befed81e11b5f1a8df8d6047d4f09e..5744392701267d10ebabad365152de3edde2251a 100644 (file)
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -398,6 +398,8 @@ void xenvif_rx_skb(struct xenvif_queue *queue)
 
        xenvif_rx_next_skb(queue, &pkt);
 
+       queue->last_rx_time = jiffies;
+
        do {
                struct xen_netif_rx_request *req;
                struct xen_netif_rx_response *rsp;