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Date: Mon, 29 Apr 2024 14:50:23 -0400
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Gavin Shan <gshan@redhat.com>
Cc: virtualization@lists.linux.dev, linux-kernel@vger.kernel.org,
	jasowang@redhat.com, shan.gavin@gmail.com
Subject: Re: [PATCH v2 0/4] vhost: Cleanup
Message-ID: <20240429144955-mutt-send-email-mst@kernel.org>
References: <20240429101400.617007-1-gshan@redhat.com>
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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-mst@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'            (ltp@intel.com)
> 
> -- 
> 2.44.0