linux-kernel - Re: [PATCH v3 2/6] iio: light: Add gain-time-scale helpers

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Message-ID: <6f94e186-2a65-15b0-be8f-7b610a28dfff@gmail.com>
Date:   Mon, 13 Mar 2023 16:25:42 +0200
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Shreeya Patel <shreeya.patel@...labora.com>,
        Paul Gazzillo <paul@...zz.com>,
        Dmitry Osipenko <dmitry.osipenko@...labora.com>,
        Zhigang Shi <Zhigang.Shi@...eon.com>,
        linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org
Subject: Re: [PATCH v3 2/6] iio: light: Add gain-time-scale helpers

On 3/13/23 16:17, Andy Shevchenko wrote:
> On Mon, Mar 13, 2023 at 03:59:03PM +0200, Matti Vaittinen wrote:
>> On 3/13/23 15:25, Andy Shevchenko wrote:
>>> On Mon, Mar 13, 2023 at 02:47:45PM +0200, Matti Vaittinen wrote:
>>>> On 3/6/23 14:52, Andy Shevchenko wrote:
>>>>> On Mon, Mar 06, 2023 at 11:17:15AM +0200, Matti Vaittinen wrote:
> 
> ...
> 
>>>>>> +	if (ret && gts->avail_all_scales_table)
>>>>>
>>>>> In one case you commented that free(NULL) is okay, in the other, you add
>>>>> a duplicative check. Why?
>>>>
>>>> Sorry but what do you mean by dublicative check?
>>>>
>>>> Usually I avoid the kfree(NULL). That's why I commented on it in that
>>>> another case where it was not explicitly disallowed. I'll change that for v4
>>>> to avoid kfree(NULL) as you suggested.
>>>
>>> So, and with it you put now a double check for NULL, do you think it's okay?
>>> I don't.
>>
>> I don't see the double check. I see only one check just above the kfree()?
>> Where is the other check?
> 
> 	if (... gts->avail_all_scales_table)
> 
> is a double to one, which is inside kfree(). I.o.w. kfree() is NULL-aware
> and you know that.

Ah. I thought you suggested I had double check in the code I wrote. Now 
I see what you meant.

Yes, I think that check should be dropped.

-- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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