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Subject: Re: [PATCH v3] net: smc91x: Fix pointer types
From: Thorsten Blum <thorsten.blum@toblux.com>
In-Reply-To: <f192113c-9aee-47be-85f6-cd19fcb81a5e@lunn.ch>
Date: Fri, 17 May 2024 01:21:04 +0200
Cc: Arnd Bergmann <arnd@arndb.de>,
 "David S. Miller" <davem@davemloft.net>,
 edumazet@google.com,
 glaubitz@physik.fu-berlin.de,
 kuba@kernel.org,
 linux-kernel@vger.kernel.org,
 lkp@intel.com,
 netdev@vger.kernel.org,
 nico@fluxnic.net,
 pabeni@redhat.com
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Message-Id: <66AB9A6F-4D24-4033-96B9-E5F2F700029D@toblux.com>
References: <0efd687d-3df5-49dd-b01c-d5bd977ae12e@lunn.ch>
 <20240516223004.350368-2-thorsten.blum@toblux.com>
 <f192113c-9aee-47be-85f6-cd19fcb81a5e@lunn.ch>
To: Andrew Lunn <andrew@lunn.ch>

On 17. May 2024, at 00:51, Andrew Lunn <andrew@lunn.ch> wrote:
> On Fri, May 17, 2024 at 12:30:05AM +0200, Thorsten Blum wrote:
>> Use void __iomem pointers as parameters for mcf_insw() and =
mcf_outsw()
>> to align with the parameter types of readw() and writew() to fix the
>> following warnings reported by kernel test robot:
>>=20
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse: warning: incorrect =
type in argument 1 (different address spaces)
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    expected void *a
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    got void =
[noderef] __iomem *
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse: warning: incorrect =
type in argument 1 (different address spaces)
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    expected void *a
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    got void =
[noderef] __iomem *
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse: warning: incorrect =
type in argument 1 (different address spaces)
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    expected void *a
>> drivers/net/ethernet/smsc/smc91x.c:590:9: sparse:    got void =
[noderef] __iomem *
>> drivers/net/ethernet/smsc/smc91x.c:483:17: sparse: warning: incorrect =
type in argument 1 (different address spaces)
>> drivers/net/ethernet/smsc/smc91x.c:483:17: sparse:    expected void =
*a
>> drivers/net/ethernet/smsc/smc91x.c:483:17: sparse:    got void =
[noderef] __iomem *
>>=20
>> Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: =
https://lore.kernel.org/oe-kbuild-all/202405160853.3qyaSj8w-lkp@intel.com/=

>> Acked-by: Nicolas Pitre <nico@fluxnic.net>
>> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
>> ---
>> Changes in v2:
>> - Use lp->base instead of __ioaddr as suggested by Andrew Lunn. They =
are
>> essentially the same, but using lp->base results in a smaller diff
>> - Remove whitespace only changes as suggested by Andrew Lunn
>> - Preserve Acked-by: Nicolas Pitre tag (please let me know if you
>> somehow disagree with the changes in v2 or v3)
>>=20
>> Changes in v3:
>> - Revert changing the macros as this is unnecessary. Neither the =
types
>>  nor the __iomem attributes get lost across macro boundaries
>> - Preserve Reviewed-by: Andrew Lunn tag (please let me know if you
>>  somehow disagree with the changes in v3)
>=20
> This fixes the warning, but we still have the macro accessing things
> not passed to them. If you are going to brother to fix the warnings,
> it would also be good to fix the bad practice. Please make a patchset
> to do this.

I would prefer to submit another patch to fix the macros. I submitted v3
because the patch description for v2 was wrong (type information or
attributes don't get lost across macro boundaries) and the macro changes
are unnecessary to fix the warnings.

I should never have changed the macros, but after first adding __iomem
to mcf_insw() and mcf_outsw(), I kept getting the same errors and looked
for the problem in the SMC_* macros. I probably didn't do a clean build
or forgot to save my changes and just refactored the macros as a side
effect.

> It would also be good if you read:
>=20
> https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

Will do.

Thanks,
Thorsten=