Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/mchehab...

[pandora-kernel.git] / kernel / time.c

diff --git a/kernel/time.c b/kernel/time.c
index f04791f..ffe1914 100644 (file)
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -57,14 +57,17 @@ EXPORT_SYMBOL(sys_tz);
  */
 asmlinkage long sys_time(time_t __user * tloc)
 {
-       time_t i;
-       struct timeval tv;
+       /*
+        * We read xtime.tv_sec atomically - it's updated
+        * atomically by update_wall_time(), so no need to
+        * even read-lock the xtime seqlock:
+        */
+       time_t i = xtime.tv_sec;
 
-       do_gettimeofday(&tv);
-       i = tv.tv_sec;
+       smp_rmb(); /* sys_time() results are coherent */
 
        if (tloc) {
-               if (put_user(i,tloc))
+               if (put_user(i, tloc))
                        i = -EFAULT;
        }
        return i;
@@ -373,12 +376,25 @@ void do_gettimeofday (struct timeval *tv)
 
        tv->tv_sec = sec;
        tv->tv_usec = usec;
-}
 
+       /*
+        * Make sure xtime.tv_sec [returned by sys_time()] always
+        * follows the gettimeofday() result precisely. This
+        * condition is extremely unlikely, it can hit at most
+        * once per second:
+        */
+       if (unlikely(xtime.tv_sec != tv->tv_sec)) {
+               unsigned long flags;
+
+               write_seqlock_irqsave(&xtime_lock, flags);
+               update_wall_time();
+               write_sequnlock_irqrestore(&xtime_lock, flags);
+       }
+}
 EXPORT_SYMBOL(do_gettimeofday);
 
+#else  /* CONFIG_TIME_INTERPOLATION */
 
-#else
 #ifndef CONFIG_GENERIC_TIME
 /*
  * Simulate gettimeofday using do_gettimeofday which only allows a timeval
@@ -394,7 +410,7 @@ void getnstimeofday(struct timespec *tv)
 }
 EXPORT_SYMBOL_GPL(getnstimeofday);
 #endif
-#endif
+#endif /* CONFIG_TIME_INTERPOLATION */
 
 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
  * Assumes input in normal date format, i.e. 1980-12-31 23:59:59