Help with compiler warning

Help with compiler warning

[Larry Finger]

In drivers/pcmcia/cardbus.c, the following statement

         memcpy_fromio(ptr, s->cb_cis_virt + addr, len);

generates the warning

   CC [M]  drivers/pcmcia/cardbus.o
include/asm/io_32.h: In function ‘memcpy_fromio’:
include/asm/io_32.h:151: warning: passing argument 2 of ‘__memcpy’ 
discards qualifiers from pointer target type

s->cb_cis_virt is "void __iomem" and addr is uint.

What cast does argument 2 need to silence the warning?

Thanks,

Larry

Re: Help with compiler warning

[Benny Halevy]

On Aug. 22, 2008, 4:36 +0300, Larry Finger <Larry.Finger@lwfinger.net> wrote:
> In drivers/pcmcia/cardbus.c, the following statement
> 
>          memcpy_fromio(ptr, s->cb_cis_virt + addr, len);
> 
> generates the warning
> 
>    CC [M]  drivers/pcmcia/cardbus.o
> include/asm/io_32.h: In function ‘memcpy_fromio’:
> include/asm/io_32.h:151: warning: passing argument 2 of ‘__memcpy’ 
> discards qualifiers from pointer target type
> 
> s->cb_cis_virt is "void __iomem" and addr is uint.
> 
> What cast does argument 2 need to silence the warning?

memcpy_fromio takes a (const volatile void __iomem *) for the 
src address.

Benny

> 
> Thanks,
> 
> Larry
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Re: Help with compiler warning

[Benny Halevy]

On Aug. 24, 2008, 18:29 +0300, Benny Halevy <bhalevy@panasas.com> wrote:
> On Aug. 22, 2008, 4:36 +0300, Larry Finger <Larry.Finger@lwfinger.net> wrote:
>> In drivers/pcmcia/cardbus.c, the following statement
>>
>>          memcpy_fromio(ptr, s->cb_cis_virt + addr, len);
>>
>> generates the warning
>>
>>    CC [M]  drivers/pcmcia/cardbus.o
>> include/asm/io_32.h: In function ‘memcpy_fromio’:
>> include/asm/io_32.h:151: warning: passing argument 2 of ‘__memcpy’ 
>> discards qualifiers from pointer target type
>>
>> s->cb_cis_virt is "void __iomem" and addr is uint.
>>
>> What cast does argument 2 need to silence the warning?
> 
> memcpy_fromio takes a (const volatile void __iomem *) for the 
> src address.

So the culprit could be the volatile qualifier...

> 
> Benny
> 
>> Thanks,
>>
>> Larry
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> 

Re: Help with compiler warning

[Larry Finger]

Benny Halevy wrote:
> On Aug. 24, 2008, 18:29 +0300, Benny Halevy <bhalevy@panasas.com> wrote:
>> On Aug. 22, 2008, 4:36 +0300, Larry Finger <Larry.Finger@lwfinger.net> wrote:
>>> In drivers/pcmcia/cardbus.c, the following statement
>>>
>>>          memcpy_fromio(ptr, s->cb_cis_virt + addr, len);
>>>
>>> generates the warning
>>>
>>>    CC [M]  drivers/pcmcia/cardbus.o
>>> include/asm/io_32.h: In function ‘memcpy_fromio’:
>>> include/asm/io_32.h:151: warning: passing argument 2 of ‘__memcpy’ 
>>> discards qualifiers from pointer target type
>>>
>>> s->cb_cis_virt is "void __iomem" and addr is uint.
>>>
>>> What cast does argument 2 need to silence the warning?
>> memcpy_fromio takes a (const volatile void __iomem *) for the 
>> src address.
> 
> So the culprit could be the volatile qualifier...

Changing it to

memcpy_fromio(ptr, (const volatile void __iomem *)(s->cb_cis_virt + 
addr), len);

memcpy_fromio(ptr, (const volatile void __iomem *)s->cb_cis_virt + 
addr, len);

memcpy_fromio(ptr, (volatile void __iomem *)(s->cb_cis_virt + addr), len);

or

memcpy_fromio(ptr, (volatile void __iomem *)s->cb_cis_virt + addr, len);

makes no difference.

Thanks,

Larry

Re: Help with compiler warning

[Andreas Schwab]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> Benny Halevy wrote:
>> On Aug. 24, 2008, 18:29 +0300, Benny Halevy <bhalevy@panasas.com> wrote:
>>> On Aug. 22, 2008, 4:36 +0300, Larry Finger <Larry.Finger@lwfinger.net> wrote:
>>>> In drivers/pcmcia/cardbus.c, the following statement
>>>>
>>>>          memcpy_fromio(ptr, s->cb_cis_virt + addr, len);
>>>>
>>>> generates the warning
>>>>
>>>>    CC [M]  drivers/pcmcia/cardbus.o
>>>> include/asm/io_32.h: In function ‘memcpy_fromio’:
>>>> include/asm/io_32.h:151: warning: passing argument 2 of ‘__memcpy’
>>>> discards qualifiers from pointer target type
>>>>
>>>> s->cb_cis_virt is "void __iomem" and addr is uint.
>>>>
>>>> What cast does argument 2 need to silence the warning?

The cast needs to be in memcpy_fromio, but there is already one, so why
do you get a warning in the first place?

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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