From 38332cb98772f5ea757e6486bed7ed0381cb5f98 Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Tue, 4 Mar 2008 14:59:54 -0800 Subject: [PATCH] time: prevent the loop in timespec_add_ns() from being optimised away Since some architectures don't support __udivdi3(). Signed-off-by: Segher Boessenkool Cc: john stultz Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- include/linux/time.h | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/include/linux/time.h b/include/linux/time.h index 2091a19..d32ef0a 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns) { ns += a->tv_nsec; while(unlikely(ns >= NSEC_PER_SEC)) { + /* The following asm() prevents the compiler from + * optimising this loop into a modulo operation. */ + asm("" : "+r"(ns)); + ns -= NSEC_PER_SEC; a->tv_sec++; } -- 1.6.0.6