[PATCH 3.10 24/54] virtio-net: dont respond to cpu hotplug notifier if were not ready

[Greg Kroah-Hartman]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@xxxxxxxxxx>

[ Upstream commit 3ab098df35f8b98b6553edc2e40234af512ba877 ]

We're trying to re-configure the affinity unconditionally in cpu hotplug
callback. This may lead the issue during resuming from s3/s4 since

- virt queues haven't been allocated at that time.
- it's unnecessary since thaw method will re-configure the affinity.

Fix this issue by checking the config_enable and do nothing is we're not ready.

The bug were introduced by commit 8de4b2f3ae90c8fc0f17eeaab87d5a951b66ee17
(virtio-net: reset virtqueue affinity when doing cpu hotplug).

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
Reviewed-by: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/virtio_net.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1097,6 +1097,11 @@ static int virtnet_cpu_callback(struct n
 {
 	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
 
+	mutex_lock(&vi->config_lock);
+
+	if (!vi->config_enable)
+		goto done;
+
 	switch(action & ~CPU_TASKS_FROZEN) {
 	case CPU_ONLINE:
 	case CPU_DOWN_FAILED:
@@ -1109,6 +1114,9 @@ static int virtnet_cpu_callback(struct n
 	default:
 		break;
 	}
+
+done:
+	mutex_unlock(&vi->config_lock);
 	return NOTIFY_OK;
 }
 


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