linux-kernel - Re: [PATCH 2/2] i2c: virtio: fix completion handling

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Message-ID: <20211019082211.ngkkkxlfcrsvfaxg@vireshk-i7>
Date:   Tue, 19 Oct 2021 13:52:11 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Vincent Whitchurch <vincent.whitchurch@...s.com>
Cc:     wsa@...nel.org, jie.deng@...el.com,
        virtualization@...ts.linux-foundation.org,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...s.com
Subject: Re: [PATCH 2/2] i2c: virtio: fix completion handling

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))
                        complete(&vi->completion);
        }

Since we already know which is the last one, we can also check at this
point if buffers for all other requests are received or not.

-- 
viresh