Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [RFC][PATCH] introduce ptr_diff() | Date | Thu, 19 Aug 2010 14:23:09 +0200 |
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Namhyung Kim <namhyung@gmail.com> writes:
> When I compiled allyesconfig'ed kernel with C=1, I got 1519 lines of > following message: > > include/linux/mm.h:599:16: warning: potentially expensive pointer subtraction > > which is around 10% of total warnings. this was caused by page_to_pfn() macro > so I think it's worth to remove it by calculating pointer subtraction > manually.
IMHO it would be better to simply disable the warning in sparse instead of uglying the code just to work around sparse bogosity. It doesnt' seem to make much sense. A subtraction followed by a shift is not expensive.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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