From 38332cb98772f5ea757e6486bed7ed0381cb5f98 Mon Sep 17 00:00:00 2001
From: Segher Boessenkool <segher@kernel.crashing.org>
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 <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>
---
 include/linux/time.h | 4 ++++
 1 file changed, 4 insertions(+)

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++;
 	}
-- 
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