Re: [PATCH v3 3/3] vhost: Improve vhost_get_avail_idx() with smp_rmb()

[Gavin Shan]

On 3/28/24 19:31, Michael S. Tsirkin wrote:
> On Thu, Mar 28, 2024 at 10:21:49AM +1000, Gavin Shan wrote:
> > All the callers of vhost_get_avail_idx() are concerned to the memory
> > barrier, imposed by smp_rmb() to ensure the order of the available
> > ring entry read and avail_idx read.
> >
> > Improve vhost_get_avail_idx() so that smp_rmb() is executed when
> > the avail_idx is advanced. With it, the callers needn't to worry
> > about the memory barrier.
> >
> > Suggested-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
>
> Previous patches are ok. This one I feel needs more work -
> first more code such as sanity checking should go into
> this function, second there's actually a difference
> between comparing to last_avail_idx and just comparing
> to the previous value of avail_idx.
> I will pick patches 1-2 and post a cleanup on top so you can
> take a look, ok?

Thanks, Michael. It's fine to me.

Thanks,
Gavin