linux-kernel - Re: [alobakin:pfcp 5/20] drivers/iio/imu/adis16475.c:363 adis16475_set_freq() warn: set

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Date:   Mon, 6 Nov 2023 12:18:04 +0100
From:   Alexander Lobakin <aleksander.lobakin@...el.com>
To:     Nuno Sá <noname.nuno@...il.com>,
        Nuno Sa <nuno.sa@...log.com>
CC:     Dan Carpenter <dan.carpenter@...aro.org>,
        <oe-kbuild@...ts.linux.dev>, <lkp@...el.com>,
        <oe-kbuild-all@...ts.linux.dev>,
        Przemek Kitszel <przemyslaw.kitszel@...el.com>,
        <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [alobakin:pfcp 5/20] drivers/iio/imu/adis16475.c:363
 adis16475_set_freq() warn: set_bit() takes a bit number

From: Nuno Sá <noname.nuno@...il.com>
Date: Mon, 06 Nov 2023 11:07:16 +0100

> Hi Olek,
> 
> On Mon, 2023-11-06 at 10:31 +0100, Alexander Lobakin wrote:
>> From: Dan Carpenter <dan.carpenter@...aro.org>
>> Date: Mon, 6 Nov 2023 11:50:03 +0300
>>
>> Hi,
>>
>>> tree:   https://github.com/alobakin/linux pfcp
>>> head:   89565e300e3d4033b8bb568774804fdc09d4f3cc
>>> commit: 945a0d6e86d97bf60f2fae88ee557ed3eae18b94 [5/20] bitops: let the compiler
>>> optimize {__,}assign_bit()
>>> config: i386-randconfig-141-20231105
>>> (https://download.01.org/0day-ci/archive/20231106/202311060647.i9XyO4ej-lkp@intel
>>> .com/config)
>>> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
>>> reproduce:
>>> (https://download.01.org/0day-ci/archive/20231106/202311060647.i9XyO4ej-lkp@intel
>>> .com/reproduce)
>>>
>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>> the same patch/commit), kindly add following tags
>>>> Reported-by: kernel test robot <lkp@...el.com>
>>>> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
>>>> Closes: https://lore.kernel.org/r/202311060647.i9XyO4ej-lkp@intel.com/
>>>
>>> smatch warnings:
>>> drivers/iio/imu/adis16475.c:363 adis16475_set_freq() warn: set_bit() takes a bit
>>> number
>>> drivers/iio/imu/adis16475.c:363 adis16475_set_freq() warn: clear_bit() takes a
>>> bit number
>>> drivers/iio/imu/adis16475.c:416 adis16475_set_filter() warn: set_bit() takes a
>>> bit number
>>> drivers/iio/imu/adis16475.c:416 adis16475_set_filter() warn: clear_bit() takes a
>>> bit number
>>>
>>> vim +363 drivers/iio/imu/adis16475.c
>>>
>>> fff7352bf7a3ce Nuno Sá 2020-04-13  357  
>>> 9da1b86865ab43 Nuno Sá 2021-09-20  358          adis_dev_unlock(&st->adis);
>>> fff7352bf7a3ce Nuno Sá 2020-04-13  359          /*
>>> fff7352bf7a3ce Nuno Sá 2020-04-13  360           * If decimation is used, then
>>> gyro and accel data will have meaningful
>>> fff7352bf7a3ce Nuno Sá 2020-04-13  361           * bits on the LSB registers.
>>> This info is used on the trigger handler.
>>> fff7352bf7a3ce Nuno Sá 2020-04-13  362           */
>>> fff7352bf7a3ce Nuno Sá 2020-04-13
>>> @363          assign_bit(ADIS16475_LSB_DEC_MASK, &st->lsb_flag, dec);
>>>
>>> assign_bit() takes a bit number like 0.  But this is passing BIT(0) so
>>> it's like BIT(BIT(0)).  Which is fine until you get to 5.
>>
>> Is this intended? There are 2 places where you pass
>> %ADIS16475_LSB_DEC_MASK and %ADIS16475_LSB_FIR_MASK, which is `BIT(0)`
>> and `BIT(1)` respectively, to assign_bit(), which takes 0, 1 etc.
>>
> 
> Sorry, I'm missing the point in here... This should be a simple mask as 
> GENMASK(1, 0) setting/clearing the bits when appropriate. Obviously,

assign_bit() does not take a bitmask as a first argument, but a bit number.

I.e. if you want to switch BIT(0), you call it like assign_bit(0, ...),
not assign_bit(BIT(0), ...). Same for the bit nr 1.

I can make and send a quick fix if you prefer.


> ADIS16475_LSB_DEC_MASK and ADIS16475_LSB_FIR_MASK are not properly defined
> :sweat_smile:
> 
> - Nuno Sá
>>
>>>
> 

Thanks,
Olek