Re: [PATCH net 1/2] virtio-net: don't respond to cpu hotplugnotifier if we're not ready

From: Michael S. Tsirkin
Date: Mon Oct 14 2013 - 07:03:58 EST


On Mon, Oct 14, 2013 at 05:56:34PM +0800, Jason Wang wrote:
> 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).
>
> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

> ---
> The patch is need for 3.8 and above.
> ---
> drivers/net/virtio_net.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index defec2b..c4bc1cc 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1116,6 +1116,11 @@ static int virtnet_cpu_callback(struct notifier_block *nfb,
> {
> 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:
> @@ -1128,6 +1133,9 @@ static int virtnet_cpu_callback(struct notifier_block *nfb,
> default:
> break;
> }
> +
> +done:
> + mutex_unlock(&vi->config_lock);
> return NOTIFY_OK;
> }
>
> --
> 1.8.1.2
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