From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH v3 1/6] virtio_scsi: remove ACCESS_ONCE() and
 smp_read_barrier_depends()
Date: Thu, 5 Jun 2014 03:11:27 -0700
Message-ID: <20140605101127.GA8633@infradead.org>
References: <1401881699-1456-1-git-send-email-pbonzini@redhat.com>
 <1401881699-1456-2-git-send-email-pbonzini@redhat.com>
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, hch@lst.de, JBottomley@Parallels.com, venkateshs@google.com, Ming Lei <tom.leiming@gmail.com>
List-Id: linux-scsi@vger.kernel.org

On Wed, Jun 04, 2014 at 01:34:54PM +0200, Paolo Bonzini wrote:
> From: Ming Lei <tom.leiming@gmail.com>
> 
> Access to tgt->req_vq is strictly serialized by spin_lock
> of tgt->tgt_lock, so the ACCESS_ONCE() isn't necessary.
> 
> smp_read_barrier_depends() in virtscsi_req_done was introduced
> to order reading req_vq and decreasing tgt->reqs, but it isn't
> needed now because req_vq is read from
> scsi->req_vqs[vq->index - VIRTIO_SCSI_VQ_BASE] instead of
> tgt->req_vq, so remove the unnecessary barrier.
> 
> Also remove related comment about the barrier.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>