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[109.64.41.91]) by smtp.gmail.com with ESMTPSA id x18sm20730927wmi.35.2020.06.07.23.45.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 Jun 2020 23:45:52 -0700 (PDT) Date: Mon, 8 Jun 2020 02:45:50 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, eperezma@redhat.com Subject: Re: [PATCH RFC v5 13/13] vhost: drop head based APIs Message-ID: <20200608023311-mutt-send-email-mst@kernel.org> References: <20200607141057.704085-1-mst@redhat.com> <20200607141057.704085-14-mst@redhat.com> <8e3f5b6f-a47b-73cd-e8e3-959d40f6c91c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8e3f5b6f-a47b-73cd-e8e3-959d40f6c91c@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 11:57:48AM +0800, Jason Wang wrote: > > On 2020/6/7 下午10:11, Michael S. Tsirkin wrote: > > Everyone's using buf APIs, no need for head based ones anymore. > > > > Signed-off-by: Michael S. Tsirkin > > --- > > drivers/vhost/vhost.c | 36 ++++++++---------------------------- > > drivers/vhost/vhost.h | 12 ------------ > > 2 files changed, 8 insertions(+), 40 deletions(-) > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index 72ee55c810c4..e6931b760b61 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -2299,12 +2299,12 @@ static int fetch_buf(struct vhost_virtqueue *vq) > > return 1; > > } > > -/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ > > +/* Revert the effect of fetch_buf. Useful for error handling. */ > > +static > > void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) > > { > > vq->last_avail_idx -= n; > > } > > -EXPORT_SYMBOL_GPL(vhost_discard_vq_desc); > > > The same question as previous version. > > Do we need to rewind cached descriptor here? > > Thanks Good point. This needs more thought, we need to also rewind the avail idx each time we flush the descriptor cache. -- MST