Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756068Ab3JNLHX (ORCPT ); Mon, 14 Oct 2013 07:07:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753874Ab3JNLHW (ORCPT ); Mon, 14 Oct 2013 07:07:22 -0400 Date: Mon, 14 Oct 2013 14:09:51 +0300 From: "Michael S. Tsirkin" To: Jason Wang Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, rusty@rustcorp.com.au Subject: Re: [PATCH net 2/2] virtio-net: refill only when device is up during setting queues Message-ID: <20131014110951.GG30954@redhat.com> References: <1381744595-26881-1-git-send-email-jasowang@redhat.com> <1381744595-26881-2-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381744595-26881-2-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1741 Lines: 47 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 > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/