Commit 9ca908f4 authored Jul 23, 2008 by Milton Miller Committed by Linus Torvalds Jul 24, 2008

kcalloc: remove runtime division



While in all cases in the kernel we know the size of the elements to be
created, we don't always know the count of elements.  By commuting the size
and count in the overflow check, the compiler can reduce the runtime division
of size_t with a compare to a (unique) constant in these cases.

Signed-off-by: Milton Miller <miltonm@bga.com>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5c755e9f

include/linux/slab.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -180,7 +180,7 @@ size_t ksize(const void *);
		*/
		static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
		{
		if (n != 0 && size > ULONG_MAX / n)
		if (size != 0 && n > ULONG_MAX / size)
		return NULL;
		return __kmalloc(n * size, flags \| __GFP_ZERO);
		}

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