On Tue, Apr 23, 2024 at 01:24:03PM +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. Gavin I suggested another approach. 1. Start with the patch I sent (vhost: order avail ring reads after index updates) just do a diff against latest. simplify error handling a bit. 2. Do any other cleanups on top. > [1] https://lore.kernel.org/virtualization/20240327075940-mutt-send-email-mst@xxxxxxxxxx/ > > PATCH[1] drops the local variable @last_avail_idx since it's equivalent > to vq->last_avail_idx > PATCH[2] 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[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 (4): > vhost: Drop variable last_avail_idx in vhost_get_vq_desc() > vhost: Improve vhost_get_avail_idx() with smp_rmb() > vhost: Improve vhost_get_avail_head() > vhost: Reformat vhost_{get, put}_user() > > drivers/vhost/vhost.c | 199 +++++++++++++++++++----------------------- > 1 file changed, 88 insertions(+), 111 deletions(-) > > -- > 2.44.0
