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

[Jie Deng]

On 2021/7/5 10:43, Viresh Kumar wrote:
> 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.


Oh, You are not right. I just found we can't remove this variable. The 
"fail" and "failed" have different

meanings for this function. We need fail to return the result.


> > > +	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.
> >
> > > +}