ntp: fix typo that makes sync_cmos_clock erratic

[sfrench/cifs-2.6.git] / kernel / time / ntp.c

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 87aa5ff931e0aa63aba54ed98be8b43c38cf411d..14a2ecf2b318f82bd87d22031da05738e3773fd4 100644 (file)
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -10,10 +10,11 @@
 
 #include <linux/mm.h>
 #include <linux/time.h>
+#include <linux/timer.h>
 #include <linux/timex.h>
 #include <linux/jiffies.h>
 #include <linux/hrtimer.h>
-
+#include <linux/capability.h>
 #include <asm/div64.h>
 #include <asm/timex.h>
 
@@ -116,13 +117,7 @@ void second_overflow(void)
                if (xtime.tv_sec % 86400 == 0) {
                        xtime.tv_sec--;
                        wall_to_monotonic.tv_sec++;
-                       /*
-                        * The timer interpolator will make time change
-                        * gradually instead of an immediate jump by one second
-                        */
-                       time_interpolator_update(-NSEC_PER_SEC);
                        time_state = TIME_OOP;
-                       clock_was_set();
                        printk(KERN_NOTICE "Clock: inserting leap second "
                                        "23:59:60 UTC\n");
                }
@@ -131,13 +126,7 @@ void second_overflow(void)
                if ((xtime.tv_sec + 1) % 86400 == 0) {
                        xtime.tv_sec++;
                        wall_to_monotonic.tv_sec--;
-                       /*
-                        * Use of time interpolator for a gradual change of
-                        * time
-                        */
-                       time_interpolator_update(NSEC_PER_SEC);
                        time_state = TIME_WAIT;
-                       clock_was_set();
                        printk(KERN_NOTICE "Clock: deleting leap second "
                                        "23:59:59 UTC\n");
                }
@@ -187,12 +176,64 @@ u64 current_tick_length(void)
        return tick_length;
 }
 
+#ifdef CONFIG_GENERIC_CMOS_UPDATE
+
+/* Disable the cmos update - used by virtualization and embedded */
+int no_sync_cmos_clock  __read_mostly;
+
+static void sync_cmos_clock(unsigned long dummy);
+
+static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
 
-void __attribute__ ((weak)) notify_arch_cmos_timer(void)
+static void sync_cmos_clock(unsigned long dummy)
 {
-       return;
+       struct timespec now, next;
+       int fail = 1;
+
+       /*
+        * If we have an externally synchronized Linux clock, then update
+        * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+        * called as close as possible to 500 ms before the new second starts.
+        * This code is run on a timer.  If the clock is set, that timer
+        * may not expire at the correct time.  Thus, we adjust...
+        */
+       if (!ntp_synced())
+               /*
+                * Not synced, exit, do not restart a timer (if one is
+                * running, let it run out).
+                */
+               return;
+
+       getnstimeofday(&now);
+       if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
+               fail = update_persistent_clock(now);
+
+       next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+       if (next.tv_nsec <= 0)
+               next.tv_nsec += NSEC_PER_SEC;
+
+       if (!fail)
+               next.tv_sec = 659;
+       else
+               next.tv_sec = 0;
+
+       if (next.tv_nsec >= NSEC_PER_SEC) {
+               next.tv_sec++;
+               next.tv_nsec -= NSEC_PER_SEC;
+       }
+       mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
 }
 
+static void notify_cmos_timer(void)
+{
+       if (!no_sync_cmos_clock)
+               mod_timer(&sync_cmos_timer, jiffies + 1);
+}
+
+#else
+static inline void notify_cmos_timer(void) { }
+#endif
+
 /* adjtimex mainly allows reading (and writing, if superuser) of
  * kernel time-keeping variables. used by xntpd.
  */
@@ -357,6 +398,6 @@ leave:      if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
        txc->stbcnt        = 0;
        write_sequnlock_irq(&xtime_lock);
        do_gettimeofday(&txc->time);
-       notify_arch_cmos_timer();
+       notify_cmos_timer();
        return(result);
 }