Commit 686a0f3d authored Oct 13, 2010 by Eric Paris Committed by James Morris Oct 21, 2010

kernel: rounddown helper function



The roundup() helper function will round a given value up to a multiple of
another given value.  aka  roundup(11, 7) would give 14 = 7 * 2.  This new
function does the opposite.  It will round a given number down to the
nearest multiple of the second number: rounddown(11, 7) would give 7.

I need this in some future SELinux code and can carry the macro myself, but
figured I would put it in the core kernel so others might find and use it
if need be.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

parent 1ae4de0c

include/linux/kernel.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -59,6 +59,12 @@ extern const char linux_proc_banner[];
		#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
		#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
		#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
		#define rounddown(x, y) ( \
		{ \
		typeof(x) __x = (x); \
		__x - (__x % (y)); \
		} \
		)
		#define DIV_ROUND_CLOSEST(x, divisor)( \
		{ \
		typeof(divisor) __divisor = divisor; \