Re: [PATCH 01/10] staging: slicoss: slic.h: add a macro IOMEM_GET_FIELDADDR to fix sparse warnings

[zerons]

these marcos are used to get the value or address of a member of a `__iomem` structure.
GET_FIELDADDR is like &iomem_obj->field, and
GET_FIELD32 is iomem_obj->u32val, GET_FIELD64 is iomem_obj->u64val.

If patch the .c file directly, the source gets into a mess.


On 09/16/2016 03:52 PM, Greg KH wrote:
> On Tue, Sep 13, 2016 at 07:59:50PM -0700, Peng Sun wrote:
>> Signed-off-by: Peng Sun <sironhide0null@xxxxxxxxx>
>> ---
>>  drivers/staging/slicoss/slic.h | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/staging/slicoss/slic.h b/drivers/staging/slicoss/slic.h
>> index fe1d2ce..7c23190 100644
>> --- a/drivers/staging/slicoss/slic.h
>> +++ b/drivers/staging/slicoss/slic.h
>> @@ -539,6 +539,13 @@ static inline void slic_flush_write(struct adapter *adapter)
>>  	ioread32(adapter->regs + SLIC_REG_HOSTID);
>>  }
>>  
>> +#define IOMEM_GET_FIELDADDR(base, member)				\
>> +({									\
>> +	char __iomem *_base = (char __iomem *)base;			\
>> +	_base += offsetof(typeof(*base), member);			\
>> +	(void __iomem *)_base;						\
>> +})
>> +
>>  #define UPDATE_STATS(largestat, newstat, oldstat)                        \
>>  {                                                                        \
>>  	if ((newstat) < (oldstat))                                       \
>> -- 
>> 2.7.4
> 
> Wait, what does this patch on its own do?  Why create this macro?
> 
> greg k-h
>