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Subjecttime: prevent the loop in timespec_add_ns() from being optimised away
-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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