linux-kernel - Re: [PATCH v2 4/7] gpio: mockup: improve readability

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Date:   Wed, 31 May 2017 17:06:20 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Bamvor Jian Zhang <bamvor.zhangjian@...aro.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/7] gpio: mockup: improve readability

2017-05-31 16:57 GMT+02:00 Andy Shevchenko <andy.shevchenko@...il.com>:
> On Wed, May 31, 2017 at 1:53 PM, Bartosz Golaszewski <brgl@...ev.pl> wrote:
>> 2017-05-30 20:55 GMT+02:00 Andy Shevchenko <andy.shevchenko@...il.com>:
>>> On Tue, May 30, 2017 at 11:58 AM, Bartosz Golaszewski <brgl@...ev.pl> wrote:
>>>> We currently shift bits here and there without actually explaining
>>>> what we're doing. Add some helper variables with names indicating
>>>> their purpose to improve the code readability.
>>>
>>>> +       /* Each chip is described by two values. */
>>>> +       num_chips = gpio_mockup_params_nr / 2;
>>>> +
>>>> +       chips = devm_kzalloc(dev, sizeof(*chips) * num_chips, GFP_KERNEL);
>>>
>>> It's effectively
>>> devm_kcalloc()
>>> or
>>> devm_kmalloc_array()
>>> depending on the requirement of zeroing a memory chunks.
>
>> Is there any advantage to using one of these here?
>
> Yes, though subtle one in this case. The caller will not care about
> (possible) overflow in multiplication.
> Other (micro)optimizations might be in place in the future as well,
> but I dunno about this.
>
> I would suggest to change.
>

Ok, I'll change it both for the lines and for the chips arrays and add
a separate patch.

Thanks,
Bartosz