On Mon, Apr 29, 2024 at 08:13:56PM +1000, Gavin Shan wrote:
> This is suggested by Michael S. Tsirkin according to [1] and the goal
> is to apply smp_rmb() inside vhost_get_avail_idx() if needed. With it,
> the caller of the function needn't to worry about memory barriers. Since
> we're here, other cleanups are also applied.
>
> [1]
> https://lore.kernel.org/virtualization/20240327155750-mutt-send-email-...@kernel.org/
Patch 1 makes some sense, gave some comments. Rest I think we should
just drop.
> PATCH[1] improves vhost_get_avail_idx() so that smp_rmb() is applied if
> needed. Besides, the sanity checks on the retrieved available
> queue index are also squeezed to vhost_get_avail_idx()
> PATCH[2] drops the local variable @last_avail_idx since it's equivalent
> to vq->last_avail_idx
> PATCH[3] improves vhost_get_avail_head(), similar to what we're doing
> for vhost_get_avail_idx(), so that the relevant sanity checks
> on the head are squeezed to vhost_get_avail_head()
> PATCH[4] Reformat vhost_{get, put}_user() by using tab instead of space
> as the terminator for each line
>
> Gavin Shan (3):
> vhost: Drop variable last_avail_idx in vhost_get_vq_desc()
> vhost: Improve vhost_get_avail_head()
> vhost: Reformat vhost_{get, put}_user()
>
> Michael S. Tsirkin (1):
> vhost: Improve vhost_get_avail_idx() with smp_rmb()
>
> drivers/vhost/vhost.c | 215 +++++++++++++++++++-----------------------
> 1 file changed, 97 insertions(+), 118 deletions(-)
>
> Changelog
> =========
> v2:
> * Improve vhost_get_avail_idx() as Michael suggested in [1]
> as above (Michael)
> * Correct @head's type from 'unsigned int' to 'int'
> (l...@intel.com)
>
> --
> 2.44.0
