[PATCH] x86_64: Fix get_cmos_time()

Due to a broken condition, the body of the loop that is intended to wait for
the Update-In-Progress bit to get set and then cleared again was never
entered; in fact, the entire loop was optimized out by the compiler. Here is
a change to fix the condition (and to also move the initialization of locals
out of the spin lock protected region).

Signed-Off-By: Jan Beulich <jbeulich@novell.com>

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 7 deletions

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 966d1376b592..f8c47c688443 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -504,8 +504,8 @@ unsigned long long sched_clock(void)
 
 static unsigned long get_cmos_time(void)
 {
-        unsigned int timeout, year, mon, day, hour, min, sec;
-        unsigned char last, this;
+        unsigned int timeout = 1000000, year, mon, day, hour, min, sec;
+        unsigned char uip = 0, this = 0;
         unsigned long flags;
 
 /*
@@ -518,11 +518,8 @@ static unsigned long get_cmos_time(void)
 
         spin_lock_irqsave(&rtc_lock, flags);
 
-        timeout = 1000000;
-        last = this = 0;
-
-        while (timeout && last && !this) {
-                last = this;
+        while (timeout && (!uip || this)) {
+                uip |= this;
                 this = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP;
                 timeout--;
         }