[0/4] virtio-net: don't busy poll for cvq command

Message

Jason Wang Dec. 26, 2022, 7:49 a.m. UTC

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 + timeout instead of busy polling.

Please review.

Thanks

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 (4):
  virtio-net: convert rx mode setting to use workqueue
  virtio_ring: switch to use BAD_RING()
  virtio_ring: introduce a per virtqueue waitqueue
  virtio-net: sleep instead of busy waiting for cvq command

 drivers/net/virtio_net.c     | 90 +++++++++++++++++++++++++++++++-----
 drivers/virtio/virtio_ring.c | 37 +++++++++++++--
 include/linux/virtio.h       |  3 ++
 3 files changed, 115 insertions(+), 15 deletions(-)