Re: [PULL 1/1] virtio-blk: don't start dataplane during the stop of dataplane

[Kevin Wolf <kwolf@redhat.com>]

Am 17.10.2023 um 11:01 hat Fiona Ebner geschrieben:
> Am 16.10.23 um 21:40 schrieb Stefan Hajnoczi:
> > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > index 39e7f23fab..c2d59389cb 100644
> > --- a/hw/block/virtio-blk.c
> > +++ b/hw/block/virtio-blk.c
> > @@ -1166,7 +1166,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> >  {
> >      VirtIOBlock *s = (VirtIOBlock *)vdev;
> >  
> > -    if (s->dataplane && !s->dataplane_started) {
> > +    if (s->dataplane && !s->dataplane_started && !s->stopping) {
> 
> Isn't 'stopping' a property of VirtIOBlockDataPlane? Here, s is VirtIOBlock.

Indeed, this patch doesn't even build for me.

However, even if we wrote !s->dataplane->stopping, would it really be
right to be handling I/O in the main thread while the dataplane hasn't
stopped yet? At least without all the multiqueue changes, it's not
obvious to me that it can't cause problems. Unfortunately, the commit
message doesn't say anything about why it's safe.

Kevin