Re: [PATCH net] virtio-net: fix the race between channels settingand refill
From: Michael S. Tsirkin
Date: Thu Jul 04 2013 - 04:22:29 EST
On Wed, Jul 03, 2013 at 08:15:52PM +0800, Jason Wang wrote:
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Commit 55257d72bd1c51f25106350f4983ec19f62ed1fa (virtio-net: fill only rx queues
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which are being used) tries to refill on demand when changing the number of
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channels by call try_refill_recv() directly, this may race:
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- the refill work who may do the refill in the same time
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- the try_refill_recv() called in bh since napi was not disabled
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Which may led guest complain during setting channels:
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virtio_net virtio0: input.1:id 0 is not a head!
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Solve this issue by scheduling a refill work which can guarantee the
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serialization of refill.
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Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
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Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
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Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
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Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
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---
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drivers/net/virtio_net.c | 5 +----
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1 files changed, 1 insertions(+), 4 deletions(-)
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diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
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index c9e0038..47b4882 100644
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--- a/drivers/net/virtio_net.c
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+++ b/drivers/net/virtio_net.c
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@@ -901,7 +901,6 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
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struct scatterlist sg;
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struct virtio_net_ctrl_mq s;
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struct net_device *dev = vi->dev;
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- int i;
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if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
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return 0;
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@@ -915,10 +914,8 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
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queue_pairs);
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return -EINVAL;
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} else {
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- for (i = vi->curr_queue_pairs; i < queue_pairs; i++)
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- if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
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- schedule_delayed_work(&vi->refill, 0);
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vi->curr_queue_pairs = queue_pairs;
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+ schedule_delayed_work(&vi->refill, 0);
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}
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return 0;
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--
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1.7.1
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