#include <linux/timex.h>
#include <linux/capability.h>
#include <linux/errno.h>
-#include <linux/smp_lock.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/fs.h>
*/
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;
}
EXPORT_SYMBOL(current_fs_time);
+/*
+ * Convert jiffies to milliseconds and back.
+ *
+ * Avoid unnecessary multiplications/divisions in the
+ * two most common HZ cases:
+ */
+unsigned int inline jiffies_to_msecs(const unsigned long j)
+{
+#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
+ return (MSEC_PER_SEC / HZ) * j;
+#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
+ return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
+#else
+ return (j * MSEC_PER_SEC) / HZ;
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_msecs);
+
+unsigned int inline jiffies_to_usecs(const unsigned long j)
+{
+#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
+ return (USEC_PER_SEC / HZ) * j;
+#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
+ return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
+#else
+ return (j * USEC_PER_SEC) / HZ;
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_usecs);
+
/**
* timespec_trunc - Truncate timespec to a granularity
* @t: Timespec
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
}
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
}
EXPORT_SYMBOL(ns_to_timeval);
-/*
- * Convert jiffies to milliseconds and back.
- *
- * Avoid unnecessary multiplications/divisions in the
- * two most common HZ cases:
- */
-unsigned int jiffies_to_msecs(const unsigned long j)
-{
-#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
- return (MSEC_PER_SEC / HZ) * j;
-#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
- return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
-#else
- return (j * MSEC_PER_SEC) / HZ;
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_msecs);
-
-unsigned int jiffies_to_usecs(const unsigned long j)
-{
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
- return (USEC_PER_SEC / HZ) * j;
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
- return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
-#else
- return (j * USEC_PER_SEC) / HZ;
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_usecs);
-
/*
* When we convert to jiffies then we interpret incoming values
* the following way: