xen-netback: stop the guest rx thread after a fatal error
After commit e9d8b2c2968499c1f96563e6522c56958d5a1d0d (xen-netback:
disable rogue vif in kthread context), a fatal (protocol) error would
leave the guest Rx thread spinning, wasting CPU time. Commit
ecf08d2dbb96d5a4b4bcc53a39e8d29cc8fef02e (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>
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 9259a73..037f74f 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -578,6 +578,7 @@
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 @@
if (queue->task) {
kthread_stop(queue->task);
+ put_task_struct(queue->task);
queue->task = NULL;
}
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 908e65e..c8ce701 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -2109,8 +2109,7 @@
*/
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))