Messages in this thread Patch in this message | | | Date | Wed, 16 Apr 2008 18:01:23 -0700 | From | Chris Wright <> | Subject | time: prevent the loop in timespec_add_ns() from being optimised away |
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-stable review patch. If anyone has any objections, please let us know. ---------------------
From: Segher Boessenkool <segher@kernel.crashing.org>
upstream commit: 38332cb98772f5ea757e6486bed7ed0381cb5f98
Since some architectures don't support __udivdi3().
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sedat Dilek <sedat.dilek@googlemail.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- include/linux/time.h | 4 ++++ 1 file changed, 4 insertions(+)
--- a/include/linux/time.h +++ b/include/linux/time.h @@ -173,6 +173,10 @@ static inline void timespec_add_ns(struc { 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++; } --
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