Re: [PATCH] ata: pata_cs5535: Fix W=1 warnings

From: Damien Le Moal
Date: Tue Jun 28 2022 - 21:15:03 EST


On 6/28/22 19:05, Sergey Shtylyov wrote:
> Hello!
>
> On 6/28/22 11:59 AM, Damien Le Moal wrote:
> [...]
>>> x86_64 allmodconfig build with W=1 gives these warnings:
>>>
>>> drivers/ata/pata_cs5535.c: In function ‘cs5535_set_piomode’:
>>> drivers/ata/pata_cs5535.c:93:11: error: variable ‘dummy’ set but not used [-Werror=unused-but-set-variable]
>>> u32 reg, dummy;
>>> ^~~~~
>>> drivers/ata/pata_cs5535.c: In function ‘cs5535_set_dmamode’:
>>> drivers/ata/pata_cs5535.c:132:11: error: variable ‘dummy’ set but not used [-Werror=unused-but-set-variable]
>>> u32 reg, dummy;
>>> ^~~~~
>>> cc1: all warnings being treated as errors
>>>
>>> Mark variables 'dummy' as "maybe unused" to satisfy when rdmsr() is
>>> stubbed, which is the same as what we already do in pata_cs5536.c .
>>>
>>> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
>
>
> Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
>
>> Looks good, but I wonder why I am not getting this warning. I always do
>> W=1 and C=1 builds. I tried allmodconfig now and I am not getting the
>> warning...
>
> I can confirm the (fatal) warnings with RedHat gcc 10.3.1... but somehow they only
> occur on x86_64 with allmodconfig indeed (which is strange)...

Compiling on x86_64 with allmodconfig with gcc 12 and sparse-0.6.4-2
(Fedora 36) does not give the warning... Weird.

>
> [...]
>
> MBR, Sergey
>


--
Damien Le Moal
Western Digital Research