diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2021-04-13 01:35:26 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-20 16:10:50 +0200 |
| commit | 496bcc8d4ff9178f913630958632f7c064df5809 (patch) | |
| tree | 30ac6ddd6801d2cbafc831f56d8f583502ecdbce /drivers/net/virtio_net.c | |
| parent | aac6a79ee0c01d87b17e1b365ae7580fde4a2df1 (diff) | |
virtio_net: move tx vq operation under tx queue lock
[ Upstream commit 5a2f966d0f3fa0ef6dada7ab9eda74cacee96b8a ]
It's unsafe to operate a vq from multiple threads.
Unfortunately this is exactly what we do when invoking
clean tx poll from rx napi.
Same happens with napi-tx even without the
opportunistic cleaning from the receive interrupt: that races
with processing the vq in start_xmit.
As a fix move everything that deals with the vq to under tx lock.
Fixes: b92f1e6751a6 ("virtio-net: transmit napi")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/net/virtio_net.c')
| -rw-r--r-- | drivers/net/virtio_net.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index af7d69719c4f..15453d6fcc23 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1504,6 +1504,8 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) struct virtnet_info *vi = sq->vq->vdev->priv; unsigned int index = vq2txq(sq->vq); struct netdev_queue *txq; + int opaque; + bool done; if (unlikely(is_xdp_raw_buffer_queue(vi, index))) { /* We don't need to enable cb for XDP */ @@ -1513,10 +1515,28 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) txq = netdev_get_tx_queue(vi->dev, index); __netif_tx_lock(txq, raw_smp_processor_id()); + virtqueue_disable_cb(sq->vq); free_old_xmit_skbs(sq, true); + + opaque = virtqueue_enable_cb_prepare(sq->vq); + + done = napi_complete_done(napi, 0); + + if (!done) + virtqueue_disable_cb(sq->vq); + __netif_tx_unlock(txq); - virtqueue_napi_complete(napi, sq->vq, 0); + if (done) { + if (unlikely(virtqueue_poll(sq->vq, opaque))) { + if (napi_schedule_prep(napi)) { + __netif_tx_lock(txq, raw_smp_processor_id()); + virtqueue_disable_cb(sq->vq); + __netif_tx_unlock(txq); + __napi_schedule(napi); + } + } + } if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) netif_tx_wake_queue(txq); |