alarmtimer: Provide get_timespec() callback

The upcoming support for time namespaces requires to have access to:

  - The time in a task's time namespace for sys_clock_gettime()
  - The time in the root name space for common_timer_get()

Wire up alarm bases with get_timespec().

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-9-dima@arista.com

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 22b6f9b..357be1f 100644 (file)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -37,12 +37,14 @@
  * @lock:              Lock for syncrhonized access to the base
  * @timerqueue:                Timerqueue head managing the list of events
  * @get_ktime:         Function to read the time correlating to the base
+ * @get_timespec:      Function to read the namespace time correlating to the base
  * @base_clockid:      clockid for the base
  */
 static struct alarm_base {
        spinlock_t              lock;
        struct timerqueue_head  timerqueue;
        ktime_t                 (*get_ktime)(void);
+       void                    (*get_timespec)(struct timespec64 *tp);
        clockid_t               base_clockid;
 } alarm_bases[ALARM_NUMTYPE];
 
@@ -670,7 +672,8 @@ static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp
        if (!alarmtimer_get_rtcdev())
                return -EINVAL;
 
-       *tp = ktime_to_timespec64(base->get_ktime());
+       base->get_timespec(tp);
+
        return 0;
 }
 
@@ -883,8 +886,10 @@ static int __init alarmtimer_init(void)
        /* Initialize alarm bases */
        alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
        alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
+       alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64,
        alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
        alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
+       alarm_bases[ALARM_BOOTTIME].get_timespec = ktime_get_boottime_ts64;
        for (i = 0; i < ALARM_NUMTYPE; i++) {
                timerqueue_init_head(&alarm_bases[i].timerqueue);
                spin_lock_init(&alarm_bases[i].lock);