Subject: Re: [PATCH 11/12]Remove defines of DMA_XXBIT_MASK micro

From: Yang Hongyang <[email-masked]>
Date: Thu, 19 Feb 2009 16:56:57 +0800

Ingo Molnar wrote:
> * Yang Hongyang <[email-masked]> wrote:
> 
>> Remove defines of DMA_XXBIT_MASK micro
>>
>> Signed-off-by: Yang Hongyang<[email-masked]>
>>
>> ---
>>  include/linux/dma-mapping.h |   20 +-------------------
>>  1 files changed, 1 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
>> index f238c7e..70f9c63 100644
>> --- a/include/linux/dma-mapping.h
>> +++ b/include/linux/dma-mapping.h
>> @@ -13,27 +13,9 @@ enum dma_data_direction {
>>  	DMA_NONE = 3,
>>  };
>>  
>> +/*use DMA_BIT_MASK(n) within your driver instead of DMA_xxBIT_MASK*/
>>  #define DMA_BIT_MASK(n)	(((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>>  
>> -/*
>> - * NOTE: do not use the below macros in new code and do not add new definitions
>> - * here.
>> - *
>> - * Instead, just open-code DMA_BIT_MASK(n) within your driver
>> - */
>> -#define DMA_64BIT_MASK	DMA_BIT_MASK(64)
>> -#define DMA_48BIT_MASK	DMA_BIT_MASK(48)
>> -#define DMA_47BIT_MASK	DMA_BIT_MASK(47)
>> -#define DMA_40BIT_MASK	DMA_BIT_MASK(40)
>> -#define DMA_39BIT_MASK	DMA_BIT_MASK(39)
>> -#define DMA_35BIT_MASK	DMA_BIT_MASK(35)
>> -#define DMA_32BIT_MASK	DMA_BIT_MASK(32)
>> -#define DMA_31BIT_MASK	DMA_BIT_MASK(31)
>> -#define DMA_30BIT_MASK	DMA_BIT_MASK(30)
>> -#define DMA_29BIT_MASK	DMA_BIT_MASK(29)
>> -#define DMA_28BIT_MASK	DMA_BIT_MASK(28)
>> -#define DMA_24BIT_MASK	DMA_BIT_MASK(24)
> 
> Looks good beyond the s/micro/macro typo fix, but i'd suggest to 
> keep these old defines for one more kernel cycle, then do a 
> final removal of all remaining uses, in a single patch.
> 
> That way we'll save ourselves from quite a bit of unnecessary 
> build breakages (as your patchset shows there's still a lot of 
> users of the old macros), as these definitions get moved around, 
> reintroduced, etc.
> 
> Conflict resolution becomes easier as well - if such a patch 
> conflicts with some ongoing work then we can by avoid the 
> conflict by just dropping that hunk and delaying that particular 
> conversion to the 'final' stage.
> 
> 	Ingo

That's a good idea,Seems it's nessary to keep these old
defines.
I will resend the patch with s/micro/macro typo fix and keep
these old defines,Thanks Ingo!~

-- 
Regards
Yang Hongyang