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From:   Jason Wang <jasowang@redhat.com>
To:     mst@redhat.com, jasowang@redhat.com
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, maxime.coquelin@redhat.com,
        alvaro.karsz@solid-run.com, eperezma@redhat.com,
        xuanzhuo@linux.alibaba.com, david.marchand@redhat.com
Subject: [PATCH net-next V2 0/2] virtio-net: don't busy poll for cvq command
Date:   Thu, 13 Apr 2023 14:40:25 +0800
Message-Id: <20230413064027.13267-1-jasowang@redhat.com>
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Hi all:

The code used to busy poll for cvq command which turns out to have
several side effects:

1) infinite poll for buggy devices
2) bad interaction with scheduler

So this series tries to use sleep instead of busy polling. In this
version, I take a step back: the hardening part is not implemented and
leave for future investigation. We use to aggree to use interruptible
sleep but it doesn't work for a general workqueue.

Please review.

Thanks

Changes since V1:
- use RTNL to synchronize rx mode worker
- use completion for simplicity
- don't try to harden CVQ command

Changes since RFC:

- switch to use BAD_RING in virtio_break_device()
- check virtqueue_is_broken() after being woken up
- use more_used() instead of virtqueue_get_buf() to allow caller to
  get buffers afterwards
  - break the virtio-net device when timeout
  - get buffer manually since the virtio core check more_used() instead

Jason Wang (2):
  virtio-net: convert rx mode setting to use workqueue
  virtio-net: sleep instead of busy waiting for cvq command

 drivers/net/virtio_net.c | 76 ++++++++++++++++++++++++++++++++++------
 1 file changed, 66 insertions(+), 10 deletions(-)

-- 
2.25.1