code.ossystems Code Review - openembedded-core.git/blob

   1 commit 38332cb98772f5ea757e6486bed7ed0381cb5f98
   2 Author: Segher Boessenkool <segher@kernel.crashing.org>
   3 Date:   Tue Mar 4 14:59:54 2008 -0800
   4
   5     time: prevent the loop in timespec_add_ns() from being optimised away
   6
   7     Since some architectures don't support __udivdi3().
   8
   9     Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
  10     Cc: john stultz <johnstul@us.ibm.com>
  11     Cc: Ingo Molnar <mingo@elte.hu>
  12     Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  13     Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  14
  15 diff --git a/include/linux/time.h b/include/linux/time.h
  16 index 2091a19..d32ef0a 100644
  17 --- a/include/linux/time.h
  18 +++ b/include/linux/time.h
  19 @@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns)
  20  {
  21         ns += a->tv_nsec;
  22         while(unlikely(ns >= NSEC_PER_SEC)) {
  23 +               /* The following asm() prevents the compiler from
  24 +                * optimising this loop into a modulo operation.  */
  25 +               asm("" : "+r"(ns));
  26 +
  27                 ns -= NSEC_PER_SEC;
  28                 a->tv_sec++;
  29         }