Re: [PATCH v7 1/7] i2c: add I2C Address Translator (ATR) support

Andy Shevchenko
2023-01-20T15:58:44Z

On Thu, Jan 19, 2023 at 12:01:33PM +0200, Tomi Valkeinen wrote:
> On 18/01/2023 16:23, Andy Shevchenko wrote:
> > On Wed, Jan 18, 2023 at 02:40:25PM +0200, Tomi Valkeinen wrote:

...

> > > + /* Ensure we have enough room to save the original addresses */
> > > + if (unlikely(chan->orig_addrs_size < num)) {
> > > + u16 *new_buf;
> > > +
> > > + new_buf = kmalloc_array(num, sizeof(*new_buf), GFP_KERNEL);
> >
> > I remember that I asked why we don't use krealloc_array() here... Perhaps
> > that we don't need to copy the old mapping table? Can we put a short comment
> > to clarify this in the code?
>
> Yes, we don't care about the old data, we just require the buffer to be
> large enough.
>
> I'm not sure what kind of comment you want here. Isn't this a common idiom,
> where you have a buffer for temporary data, but you might need to resize at
> some point if you need a larger one?

Then why not krealloc_array()? That's the question I want to see the answer for
in the comments:

/* We don't care about old data, hence no realloc() */

> > > + if (!new_buf)
> > > + return -ENOMEM;
> > > +
> > > + kfree(chan->orig_addrs);
> > > + chan->orig_addrs = new_buf;
> > > + chan->orig_addrs_size = num;
> > > + }

--
With Best Regards,
Andy Shevchenko