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xen-netback: stop the guest rx thread after a fatal error 

After commit e9d8b2c296 (xen-netback:
disable rogue vif in kthread context), a fatal (protocol) error would
leave the guest Rx thread spinning, wasting CPU time.  Commit
ecf08d2dbb (xen-netback: reintroduce
guest Rx stall detection) made this even worse by removing a
cond_resched() from this path.

Since a fatal error is non-recoverable, just allow the guest Rx thread
to exit.  This requires taking additional refs to the task so the
thread exiting early is handled safely.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Julien Grall <julien.grall@linaro.org>
Tested-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Vrabel 2015-02-02 16:57:51 +00:00 committed by David S. Miller
parent 5a2e87b168
commit 42b5212fee
2 changed files with 3 additions and 2 deletions
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2
drivers/net/xen-netback/interface.c
View File

@ -578,6 +578,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
goto err_rx_unbind; goto err_rx_unbind;
} }
queue->task = task; queue->task = task;
get_task_struct(task);
task = kthread_create(xenvif_dealloc_kthread, task = kthread_create(xenvif_dealloc_kthread,
(void *)queue, "%s-dealloc", queue->name); (void *)queue, "%s-dealloc", queue->name);
@ -634,6 +635,7 @@ void xenvif_disconnect(struct xenvif *vif)
if (queue->task) { if (queue->task) {
kthread_stop(queue->task); kthread_stop(queue->task);
put_task_struct(queue->task);
queue->task = NULL; queue->task = NULL;
} }

3
drivers/net/xen-netback/netback.c
View File

@ -2109,8 +2109,7 @@ int xenvif_kthread_guest_rx(void *data)
*/ */
if (unlikely(vif->disabled && queue->id == 0)) { if (unlikely(vif->disabled && queue->id == 0)) {
xenvif_carrier_off(vif); xenvif_carrier_off(vif);
xenvif_rx_queue_purge(queue); break;
continue;
} }
if (!skb_queue_empty(&queue->rx_queue)) if (!skb_queue_empty(&queue->rx_queue))