Re: [PATCH net-next] xen-netback: Fix vif->disable handling

From: Sergei Shtylyov
Date: Wed Aug 06 2014 - 16:31:42 EST


Hello.

On 08/06/2014 11:33 PM, Zoltan Kiss wrote:

In the patch called "xen-netback: Turn off the carrier if the guest is not able
to receive" new branches were introduced to this if statement, risking that a
queue with non-zero id can reenable the disabled interface.

Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index aa20933..f84516f 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -2027,7 +2027,13 @@ int xenvif_kthread_guest_rx(void *data)
*/
if (unlikely(queue->vif->disabled && queue->id == 0))
xenvif_carrier_off(queue->vif);
- else if (unlikely(test_and_clear_bit(QUEUE_STATUS_RX_PURGE_EVENT,
+ else if (unlikely(queue->vif->disabled)) {

Perhaps it's time to fix the coding style and add {} around the first arm of the *if* statement?

+ /* kthread_stop() would be called upon this thread soon,
+ * be a bit proactive
+ */
+ skb_queue_purge(&queue->rx_queue);
+ queue->rx_last_skb_slots = 0;
+ } else if (unlikely(test_and_clear_bit(QUEUE_STATUS_RX_PURGE_EVENT,
&queue->status))) {
xenvif_rx_purge_event(queue);
} else if (!netif_carrier_ok(queue->vif->dev)) {

WBR, Sergei

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