linux-kernel - Re: [PATCH] i2c-HID: Delete unnecessary checks before the function call "gpiod

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Message-ID: <CAN+gG=EWxh3BzOucHwMrxNByy-yEJ8Xc_tW31aiq2rbeSAZ+Rw@mail.gmail.com>
Date:	Thu, 9 Jul 2015 14:38:40 -0400
From:	Benjamin Tissoires <benjamin.tissoires@...il.com>
To:	Jiri Kosina <jkosina@...e.com>
Cc:	SF Markus Elfring <elfring@...rs.sourceforge.net>,
	linux-input <linux-input@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH] i2c-HID: Delete unnecessary checks before the function
 call "gpiod_put"

On Thu, Jul 9, 2015 at 8:34 AM, Jiri Kosina <jkosina@...e.com> wrote:
> On Wed, 8 Jul 2015, SF Markus Elfring wrote:
>
>> From: Markus Elfring <elfring@...rs.sourceforge.net>
>> Date: Wed, 8 Jul 2015 22:12:25 +0200
>>
>> The gpiod_put() function performs also input parameter validation
>> by forwarding its single input pointer to the gpiod_free() function.
>> Thus the test around the calls is not needed.
>>
>> This issue was detected by using the Coccinelle software.
>>
>> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
>
> As Dan correctly pointed out, this is not as straightforward as it might
> seem on a firsr sight, because there is a WARN_ON() that might start
> triggering in case of !ihid->desc.
>
> Adding Benjamin. I am not applying this without his Ack.
>

I think the gpiod case is the exception rather than the common rule
(most i2c-hid device we saw until recently were using irqs, not
gpios). So if I understand correctly, removing the check on ihid->desc
would raise a warning for most devices. This is IMO not a good thing,
so I would say NACK.

Mika might have a different opinion though.

Cheers,
Benjamin
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