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| author | Segher Boessenkool <segher@kernel.crashing.org> | 2008-03-04 23:59:54 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-03-09 08:42:57 +0100 |
| commit | 38332cb98772f5ea757e6486bed7ed0381cb5f98 (patch) | |
| tree | 5690b915ed9e9a64e67520df70329081900dca85 | |
| parent | ntp: use unsigned input for do_div() (diff) | |
| download | linux-38332cb98772f5ea757e6486bed7ed0381cb5f98.tar.xz linux-38332cb98772f5ea757e6486bed7ed0381cb5f98.zip | |
time: prevent the loop in timespec_add_ns() from being optimised away
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>
| -rw-r--r-- | 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 2091a19f1655..d32ef0ad4c0a 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++; } |