From a2026e44eff5d74a83d7ffee6325a007bef85385 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 4 Apr 2022 16:47:55 +0200 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/87h778j46c.ffs@tglx --- kernel/time/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 204d6cd..60aebf2 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -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); } -- 2.7.4