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Commit 42b5212f authored by David Vrabel's avatar David Vrabel Committed by David S. Miller
Browse files

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



After commit e9d8b2c2 (xen-netback:
disable rogue vif in kthread context), a fatal (protocol) error would
leave the guest Rx thread spinning, wasting CPU time.  Commit
ecf08d2d (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: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reported-by: default avatarJulien Grall <julien.grall@linaro.org>
Tested-by: default avatarJulien Grall <julien.grall@linaro.org>
Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5a2e87b1

drivers/net/xen-netback/interface.c

+2 −0
Original line number Diff line number Diff line
@@ -578,6 +578,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref, 
		goto err_rx_unbind;

	}

	queue->task = task;

	get_task_struct(task);



	task = kthread_create(xenvif_dealloc_kthread,

			      (void *)queue, "%s-dealloc", queue->name);
@@ -634,6 +635,7 @@ void xenvif_disconnect(struct xenvif *vif) 


		if (queue->task) {

			kthread_stop(queue->task);

			put_task_struct(queue->task);

			queue->task = NULL;

		}

drivers/net/xen-netback/netback.c

+1 −2
Original line number Diff line number Diff line
@@ -2109,8 +2109,7 @@ int xenvif_kthread_guest_rx(void *data) 
		 */

		if (unlikely(vif->disabled && queue->id == 0)) {

			xenvif_carrier_off(vif);

			xenvif_rx_queue_purge(queue);

			continue;

			break;

		}



		if (!skb_queue_empty(&queue->rx_queue))