[PATCH v2 0/3] virtio: Re-enable notifications after drain

[Hanna Czenczek <hreitz@redhat.com>]

v1:

https://lists.nongnu.org/archive/html/qemu-block/2024-01/msg00336.html


Hi,

This is basically the same series as v1: When using
aio_set_event_notifier_poll(), the io_poll_end() callback is only
invoked when polling ends, not when the notifier is being removed while
in a polling section.  This can leave the virtqueue notifier disabled
during drained sections, which however is not a bad thing.  We just need
to ensure they are re-enabled after the drain, and kick the virtqueue
once to pick up all the requests that came in during the drained
section.

Patch 1 is a technically unrelated fix, but addresses a problem that
became visible with patch 2 applied.

Patch 3 is a small (optional) clean-up patch.


v2:
- Changed the title of this series and patch 2 (was: "Keep notifications
  disabled durin drain"): Keeping the notifier disabled was something
  the initial RFC did, this version (v1 too) just ensures the notifier
  is enabled after the drain, regardless of its state before.

- Use event_notifier_set() instead of virtio_queue_notify() in patch 2

- Added patch 3


Hanna Czenczek (3):
  virtio-scsi: Attach event vq notifier with no_poll
  virtio: Re-enable notifications after drain
  virtio-blk: Use ioeventfd_attach in start_ioeventfd

 include/block/aio.h   |  7 ++++++-
 hw/block/virtio-blk.c | 21 ++++++++++-----------
 hw/scsi/virtio-scsi.c |  7 ++++++-
 hw/virtio/virtio.c    | 42 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 64 insertions(+), 13 deletions(-)

-- 
2.43.0