Commit de9330d1 authored Feb 06, 2008 by Robert P. J. Day Committed by Linus Torvalds Feb 06, 2008

log2.h: Define order_base_2() macro for convenience.



Given a number of places in the tree that need to calculate this value
explicitly, might as well just create a macro for it.

(akpm: must be implemented as a macro for callee typeof() usage)

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 582539e5

include/linux/log2.h

+16 −0

Original line number	Diff line number	Diff line
		@@ -190,4 +190,20 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
		__rounddown_pow_of_two(n) \
		)

		/**
		* order_base_2 - calculate the (rounded up) base 2 order of the argument
		* @n: parameter
		*
		* The first few values calculated by this routine:
		* ob2(0) = 0
		* ob2(1) = 0
		* ob2(2) = 1
		* ob2(3) = 2
		* ob2(4) = 2
		* ob2(5) = 3
		* ... and so on.
		*/

		#define order_base_2(n) ilog2(roundup_pow_of_two(n))

		#endif /* _LINUX_LOG2_H */