Re: [PATCH 1/1] unify DMA_..BIT_MASK definitions: v3.1

[Andreas Schwab]

"Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> writes:

> On Fri, 5 Oct 2007, Andrew Morton wrote:
>
>> -#define DMA_BIT_MASK(n)	((1ULL<<(n))-1)
>> +#define DMA_BIT_MASK(n)	(((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>
> or you could take advantage of the macros in kernel.h and write that
> as:
>
> +#define DMA_BIT_MASK(n)      (((n) == 64) ? ULLONG_MAX : ((1ULL<<(n))-1))

#define DMA_BIT_MASK(n)         ((u64)-1 >> (64 - (n)))

Andreas.

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