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SubjectRe: [PATCH net 2/2] virtio-net: refill only when device is up during setting queues
On Mon, Oct 14, 2013 at 05:56:35PM +0800, Jason Wang wrote:
> We used to schedule the refill work unconditionally after changing the
> number of queues. This may lead an issue if the device is not
> up. Since we only try to cancel the work in ndo_stop(), this may cause
> the refill work still work after removing the device. Fix this by only
> schedule the work when device is up.
>
> The bug were introduce by commit 9b9cd8024a2882e896c65222aa421d461354e3f2.
> (virtio-net: fix the race between channels setting and refill)
>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

It bothers me that we look at the flag without any
locks here.
I think we'll need to take the rtnl lock at least
on restore.

> ---
> The patch were need for 3.10 and above.
> ---
> drivers/net/virtio_net.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c4bc1cc..92f0096 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -938,7 +938,9 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
> return -EINVAL;
> } else {
> vi->curr_queue_pairs = queue_pairs;
> - schedule_delayed_work(&vi->refill, 0);
> + /* virtnet_open() will refill when device is going to up. */
> + if (dev->flags & IFF_UP)
> + schedule_delayed_work(&vi->refill, 0);
> }
>
> return 0;
> --
> 1.8.1.2


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