On Fri, Oct 10, 2008 at 09:46:33AM -0700, Yinghai Lu wrote: > Matthew Wilcox wrote: > > > > By the way, commit 8f286c33f1e838d631f4a3260b33efce4bc5973c is a really > > bad idea. It is very helpful to see which bitmasks are used by real > > devices, and which ones aren't. It should be reverted, IMO. > > why? did you point to wrong commit? No, that's the commit I meant. > commit 8f286c33f1e838d631f4a3260b33efce4bc5973c > Author: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Date: Thu Oct 18 03:05:07 2007 -0700 > > -#define DMA_BIT_MASK(n) ((1ULL<<(n))-1) > +#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) > > -#define DMA_64BIT_MASK (~0ULL) > +/* > + * 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 Open-coding DMA_BIT_MASK() within your driver means that we no longer have a canonical list of DMA masks in one place. Instead we have to grep the entire tree and come up with more-or-less complex scripts to figure out which bit masks are actually in use. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
