Re: [PATCH 01/12] virtio-scsi: replace AioContext lock with tmf_bh_lock

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Thu, Nov 30, 2023 at 09:25:52AM -0600, Eric Blake wrote:
> On Wed, Nov 29, 2023 at 02:55:42PM -0500, Stefan Hajnoczi wrote:
> > Protect the Task Management Function BH state with a lock. The TMF BH
> > runs in the main loop thread. An IOThread might process a TMF at the
> > same time as the TMF BH is running. Therefore tmf_bh_list and tmf_bh
> > must be protected by a lock.
> > 
> > Run TMF request completion in the IOThread using aio_wait_bh_oneshot().
> > This avoids more locking to protect the virtqueue and SCSI layer state.
> 
> Are we trying to get this into 8.2?

No. 8.2 still has the AioContext lock is therefore safe without this
patch.

Stefan

> 
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  include/hw/virtio/virtio-scsi.h |  3 +-
> >  hw/scsi/virtio-scsi.c           | 62 ++++++++++++++++++++++-----------
> >  2 files changed, 43 insertions(+), 22 deletions(-)
> >
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> 
> -- 
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.
> Virtualization:  qemu.org | libguestfs.org
> 

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