From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Jie Deng <jie.deng@intel.com>, "wsa@kernel.org" <wsa@kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kernel <kernel@axis.com>
Subject: Re: [PATCH 2/2] i2c: virtio: fix completion handling
Date: Wed, 20 Oct 2021 12:38:49 +0200 [thread overview]
Message-ID: <20211020103849.GA9985@axis.com> (raw)
In-Reply-To: <20211020091721.7kcihpevzf7h4d62@vireshk-i7>
On Wed, Oct 20, 2021 at 11:17:21AM +0200, Viresh Kumar wrote:
> On 20-10-21, 16:54, Jie Deng wrote:
> >
> > On 2021/10/19 16:22, Viresh Kumar wrote:
> > > On 19-10-21, 09:46, Vincent Whitchurch wrote:
> > > > static void virtio_i2c_msg_done(struct virtqueue *vq)
> > > > {
> > > > - struct virtio_i2c *vi = vq->vdev->priv;
> > > > + struct virtio_i2c_req *req;
> > > > + unsigned int len;
> > > > - complete(&vi->completion);
> > > > + while ((req = virtqueue_get_buf(vq, &len)))
> > > > + complete(&req->completion);
> > > Instead of adding a completion for each request and using only the
> > > last one, maybe we can do this instead here:
> > >
> > > while ((req = virtqueue_get_buf(vq, &len))) {
> > > if (req->out_hdr.flags == cpu_to_le32(VIRTIO_I2C_FLAGS_FAIL_NEXT))
> >
> >
> > Is this for the last one check ? For the last one, this bit should be
> > cleared, right ?
>
> Oops, you are right. This should be `!=` instead. Thanks.
I don't quite understand how that would be safe since
virtqueue_add_sgs() can fail after a few iterations and all queued
request buffers can have FAIL_NEXT set. In such a case, we would end up
waiting forever with your proposed change, wouldn't we?
next prev parent reply other threads:[~2021-10-20 10:38 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 7:46 [PATCH 0/2] virtio-i2c: Fix buffer handling Vincent Whitchurch
2021-10-19 7:46 ` [PATCH 1/2] i2c: virtio: disable timeout handling Vincent Whitchurch
2021-10-19 8:09 ` Viresh Kumar
2021-10-19 9:36 ` Greg KH
2021-10-19 9:42 ` Viresh Kumar
2021-10-19 11:15 ` Wolfram Sang
2021-10-19 14:14 ` Viresh Kumar
2021-10-19 11:16 ` Greg KH
2021-10-19 14:37 ` Viresh Kumar
2021-10-19 18:14 ` Wolfram Sang
2021-10-20 4:20 ` Jie Deng
2021-10-20 5:36 ` Greg KH
2021-10-20 6:35 ` Jie Deng
2021-10-20 6:41 ` Viresh Kumar
2021-10-20 7:04 ` Jie Deng
2021-10-20 10:55 ` Vincent Whitchurch
2021-10-20 11:03 ` Viresh Kumar
2021-10-21 3:30 ` Jie Deng
2021-10-29 12:24 ` Vincent Whitchurch
2021-11-01 5:23 ` Jie Deng
2021-11-03 6:18 ` Chen, Conghui
2021-11-03 6:37 ` Viresh Kumar
2021-11-03 14:42 ` Vincent Whitchurch
2021-11-09 4:52 ` Viresh Kumar
2021-10-20 3:36 ` Jie Deng
2021-10-19 7:46 ` [PATCH 2/2] i2c: virtio: fix completion handling Vincent Whitchurch
2021-10-19 8:22 ` Viresh Kumar
2021-10-20 8:54 ` Jie Deng
2021-10-20 9:17 ` Viresh Kumar
2021-10-20 10:38 ` Vincent Whitchurch [this message]
2021-10-20 10:47 ` Viresh Kumar
2021-10-29 11:54 ` Vincent Whitchurch
2021-10-21 5:55 ` Jie Deng
2021-10-21 5:58 ` Viresh Kumar
2021-11-02 4:32 ` Viresh Kumar
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