linux-kernel - Re: [PATCH v12] i2c: virtio: add a virtio i2c frontend driver

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Date:   Mon, 5 Jul 2021 08:13:40 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Jie Deng <jie.deng@...el.com>, linux-i2c@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, wsa@...nel.org,
        wsa+renesas@...g-engineering.com, mst@...hat.com, arnd@...db.de,
        jasowang@...hat.com, yu1.wang@...el.com, shuo.a.liu@...el.com,
        conghui.chen@...el.com, stefanha@...hat.com
Subject: Re: [PATCH v12] i2c: virtio: add a virtio i2c frontend driver

On 02-07-21, 12:58, Andy Shevchenko wrote:
> On Fri, Jul 02, 2021 at 04:46:47PM +0800, Jie Deng wrote:
> > +static int virtio_i2c_complete_reqs(struct virtqueue *vq,
> > +				    struct virtio_i2c_req *reqs,
> > +				    struct i2c_msg *msgs, int nr,
> > +				    bool fail)
> > +{
> > +	struct virtio_i2c_req *req;
> > +	bool failed = fail;

Jie, you can actually get rid of this variable too. Jut rename fail to failed
and everything shall work as you want.

> > +	unsigned int len;
> > +	int i, j = 0;
> > +
> > +	for (i = 0; i < nr; i++) {
> > +		/* Detach the ith request from the vq */
> > +		req = virtqueue_get_buf(vq, &len);
> > +
> > +		/*
> > +		 * Condition (req && req == &reqs[i]) should always meet since
> > +		 * we have total nr requests in the vq.
> > +		 */
> > +		if (!failed && (WARN_ON(!(req && req == &reqs[i])) ||
> > +		    (req->in_hdr.status != VIRTIO_I2C_MSG_OK)))
> > +			failed = true;
> 
> ...and after failed is true, we are continuing the loop, why?

Actually this function can be called with fail set to true. We proceed as we
need to call i2c_put_dma_safe_msg_buf() for all buffers we allocated earlier.

> > +		i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], !failed);
> > +		if (!failed)
> 
> > +			++j;
> 
> Besides better to read j++ the j itself can be renamed to something more
> verbose.
> 
> > +	}
> 
> > +	return (fail ? -ETIMEDOUT : j);
> 
> Redundant parentheses.
> 
> > +}

-- 
viresh