From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: [PATCH] virtio_net: set/cancel work on ndo_open/ndo_stop Date: Thu, 29 Dec 2011 21:12:38 +1030 Message-ID: <87pqf7fyld.fsf@rustcorp.com.au> References: <87hb0kgiwn.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Michael S. Tsirkin" To: netdev Return-path: Received: from ozlabs.org ([203.10.76.45]:53404 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752614Ab1L2Koo (ORCPT ); Thu, 29 Dec 2011 05:44:44 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Michael S. Tsirkin noticed that we could run the refill work after ndo_close, which can re-enable napi - we don't disable it until virtnet_remove. This is clearly wrong, so move the workqueue control to ndo_open and ndo_stop (aka. virtnet_open and virtnet_close). One subtle point: virtnet_probe() could simply fail if it couldn't allocate a receive buffer, but that's less polite in virtnet_open() so we schedule a refill as we do in the normal receive path if we run out of memory. Signed-off-by: Rusty Russell --- drivers/net/virtio_net.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -439,7 +439,13 @@ static int add_recvbuf_mergeable(struct return err; } -/* Returns false if we couldn't fill entirely (OOM). */ +/* + * Returns false if we couldn't fill entirely (OOM). + * + * Normally run in the receive path, but can also be run from ndo_open + * before we're receiving packets, or from refill_work which is + * careful to disable receiving (using napi_disable). + */ static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp) { int err; @@ -719,6 +725,10 @@ static int virtnet_open(struct net_devic { struct virtnet_info *vi = netdev_priv(dev); + /* Make sure we have some buffers: if oom use wq. */ + if (!try_fill_recv(vi, GFP_KERNEL)) + schedule_delayed_work(&vi->refill, 0); + virtnet_napi_enable(vi); return 0; } @@ -772,6 +782,8 @@ static int virtnet_close(struct net_devi { struct virtnet_info *vi = netdev_priv(dev); + /* Make sure refill_work doesn't re-enable napi! */ + cancel_delayed_work_sync(&vi->refill); napi_disable(&vi->napi); return 0; @@ -1082,7 +1094,6 @@ static int virtnet_probe(struct virtio_d unregister: unregister_netdev(dev); - cancel_delayed_work_sync(&vi->refill); free_vqs: vdev->config->del_vqs(vdev); free_stats: @@ -1121,9 +1132,7 @@ static void __devexit virtnet_remove(str /* Stop all the virtqueues. */ vdev->config->reset(vdev); - unregister_netdev(vi->dev); - cancel_delayed_work_sync(&vi->refill); /* Free unused buffers in both send and recv, if any. */ free_unused_bufs(vi);