Commit a2026e44 authored Apr 04, 2022 by Thomas Gleixner

timers: Simplify calc_index()



The level granularity round up of calc_index() does:

   (x + (1 << n)) >> n

which is obviously equivalent to

   (x >> n) + 1

but compilers can't figure that out despite the fact that the input range
is known to not cause an overflow. It's neither intuitive to read.

Just write out the obvious.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/87h778j46c.ffs@tglx

parent 2731aa7d

kernel/time/timer.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -502,7 +502,7 @@ static inline unsigned calc_index(unsigned long expires, unsigned lvl,
		*
		* Round up with level granularity to prevent this.
		*/
		expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl);
		expires = (expires >> LVL_SHIFT(lvl)) + 1;
		*bucket_expiry = expires << LVL_SHIFT(lvl);
		return LVL_OFFS(lvl) + (expires & LVL_MASK);
		}