Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756458Ab3GDIWY (ORCPT ); Thu, 4 Jul 2013 04:22:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21379 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755992Ab3GDIWV (ORCPT ); Thu, 4 Jul 2013 04:22:21 -0400 Date: Thu, 4 Jul 2013 11:23:22 +0300 From: "Michael S. Tsirkin" To: Jason Wang Cc: rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Sasha Levin Subject: Re: [PATCH net] virtio-net: fix the race between channels setting and refill Message-ID: <20130704082322.GB29342@redhat.com> References: <1372853752-41889-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1372853752-41889-1-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: 2088 Lines: 57 On Wed, Jul 03, 2013 at 08:15:52PM +0800, Jason Wang wrote: > Commit 55257d72bd1c51f25106350f4983ec19f62ed1fa (virtio-net: fill only rx queues > which are being used) tries to refill on demand when changing the number of > channels by call try_refill_recv() directly, this may race: > > - the refill work who may do the refill in the same time > - the try_refill_recv() called in bh since napi was not disabled > > Which may led guest complain during setting channels: > > virtio_net virtio0: input.1:id 0 is not a head! > > Solve this issue by scheduling a refill work which can guarantee the > serialization of refill. > > Cc: Sasha Levin > Cc: Rusty Russell > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin > --- > drivers/net/virtio_net.c | 5 +---- > 1 files changed, 1 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index c9e0038..47b4882 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -901,7 +901,6 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs) > struct scatterlist sg; > struct virtio_net_ctrl_mq s; > struct net_device *dev = vi->dev; > - int i; > > if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ)) > return 0; > @@ -915,10 +914,8 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs) > queue_pairs); > return -EINVAL; > } else { > - for (i = vi->curr_queue_pairs; i < queue_pairs; i++) > - if (!try_fill_recv(&vi->rq[i], GFP_KERNEL)) > - schedule_delayed_work(&vi->refill, 0); > vi->curr_queue_pairs = queue_pairs; > + schedule_delayed_work(&vi->refill, 0); > } > > return 0; > -- > 1.7.1 -- 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/