Commit 9c71a2e8 authored by Andrei Vagin's avatar Andrei Vagin Committed by Thomas Gleixner
Browse files

posix-clocks: Introduce clock_get_ktime() callback 



The callsite in common_timer_get() has already a comment:
    /*
     * The timespec64 based conversion is suboptimal, but it's not
     * worth to implement yet another callback.
     */
    kc->clock_get(timr->it_clock, &ts64);
    now = timespec64_to_ktime(ts64);

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()

That adds a valid reason to finally implement a separate callback which
returns the time in ktime_t format.

Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Co-developed-by: default avatarDmitry Safonov <dima@arista.com>
Signed-off-by: default avatarAndrei Vagin <avagin@gmail.com>
Signed-off-by: default avatarDmitry Safonov <dima@arista.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-10-dima@arista.com
parent 2f58bf90

kernel/time/alarmtimer.c

+18 −1
Original line number Diff line number Diff line
@@ -663,7 +663,7 @@ static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp 
 * @which_clock: clockid

 * @tp: timespec to fill.

 *

 * Provides the underlying alarm base time.

 * Provides the underlying alarm base time in a tasks time namespace.

 */

static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)

{
@@ -677,6 +677,22 @@ static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp 
	return 0;

}



/**

 * alarm_clock_get_ktime - posix clock_get_ktime interface

 * @which_clock: clockid

 *

 * Provides the underlying alarm base time in the root namespace.

 */

static ktime_t alarm_clock_get_ktime(clockid_t which_clock)

{

	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];



	if (!alarmtimer_get_rtcdev())

		return -EINVAL;



	return base->get_ktime();

}



/**

 * alarm_timer_create - posix timer_create interface

 * @new_timer: k_itimer pointer to manage
@@ -840,6 +856,7 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags, 


const struct k_clock alarm_clock = {

	.clock_getres		= alarm_clock_getres,

	.clock_get_ktime	= alarm_clock_get_ktime,

	.clock_get_timespec	= alarm_clock_get_timespec,

	.timer_create		= alarm_timer_create,

	.timer_set		= common_timer_set,

kernel/time/posix-timers.c

+25 −1
Original line number Diff line number Diff line
@@ -171,6 +171,11 @@ static int posix_get_realtime_timespec(clockid_t which_clock, struct timespec64 
	return 0;

}



static ktime_t posix_get_realtime_ktime(clockid_t which_clock)

{

	return ktime_get_real();

}



/* Set clock_realtime */

static int posix_clock_realtime_set(const clockid_t which_clock,

				    const struct timespec64 *tp)
@@ -193,6 +198,11 @@ static int posix_get_monotonic_timespec(clockid_t which_clock, struct timespec64 
	return 0;

}



static ktime_t posix_get_monotonic_ktime(clockid_t which_clock)

{

	return ktime_get();

}



/*

 * Get monotonic-raw time for posix timers

 */
@@ -228,12 +238,22 @@ static int posix_get_boottime_timespec(const clockid_t which_clock, struct times 
	return 0;

}



static ktime_t posix_get_boottime_ktime(const clockid_t which_clock)

{

	return ktime_get_boottime();

}



static int posix_get_tai_timespec(clockid_t which_clock, struct timespec64 *tp)

{

	ktime_get_clocktai_ts64(tp);

	return 0;

}



static ktime_t posix_get_tai_ktime(clockid_t which_clock)

{

	return ktime_get_clocktai();

}



static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)

{

	tp->tv_sec = 0;
@@ -781,7 +801,7 @@ static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires, 
	 * Posix magic: Relative CLOCK_REALTIME timers are not affected by

	 * clock modifications, so they become CLOCK_MONOTONIC based under the

	 * hood. See hrtimer_init(). Update timr->kclock, so the generic

	 * functions which use timr->kclock->clock_get_timespec() work.

	 * functions which use timr->kclock->clock_get_*() work.

	 *

	 * Note: it_clock stays unmodified, because the next timer_set() might

	 * use ABSTIME, so it needs to switch back.
@@ -1262,6 +1282,7 @@ SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags, 
static const struct k_clock clock_realtime = {

	.clock_getres		= posix_get_hrtimer_res,

	.clock_get_timespec	= posix_get_realtime_timespec,

	.clock_get_ktime	= posix_get_realtime_ktime,

	.clock_set		= posix_clock_realtime_set,

	.clock_adj		= posix_clock_realtime_adj,

	.nsleep			= common_nsleep,
@@ -1280,6 +1301,7 @@ static const struct k_clock clock_realtime = { 
static const struct k_clock clock_monotonic = {

	.clock_getres		= posix_get_hrtimer_res,

	.clock_get_timespec	= posix_get_monotonic_timespec,

	.clock_get_ktime	= posix_get_monotonic_ktime,

	.nsleep			= common_nsleep,

	.timer_create		= common_timer_create,

	.timer_set		= common_timer_set,
@@ -1310,6 +1332,7 @@ static const struct k_clock clock_monotonic_coarse = { 


static const struct k_clock clock_tai = {

	.clock_getres		= posix_get_hrtimer_res,

	.clock_get_ktime	= posix_get_tai_ktime,

	.clock_get_timespec	= posix_get_tai_timespec,

	.nsleep			= common_nsleep,

	.timer_create		= common_timer_create,
@@ -1326,6 +1349,7 @@ static const struct k_clock clock_tai = { 


static const struct k_clock clock_boottime = {

	.clock_getres		= posix_get_hrtimer_res,

	.clock_get_ktime	= posix_get_boottime_ktime,

	.clock_get_timespec	= posix_get_boottime_timespec,

	.nsleep			= common_nsleep,

	.timer_create		= common_timer_create,

kernel/time/posix-timers.h

+3 −0
Original line number Diff line number Diff line
@@ -6,8 +6,11 @@ struct k_clock { 
				struct timespec64 *tp);

	int	(*clock_set)(const clockid_t which_clock,

			     const struct timespec64 *tp);

	/* Returns the clock value in the current time namespace. */

	int	(*clock_get_timespec)(const clockid_t which_clock,

				      struct timespec64 *tp);

	/* Returns the clock value in the root time namespace. */

	ktime_t	(*clock_get_ktime)(const clockid_t which_clock);

	int	(*clock_adj)(const clockid_t which_clock, struct __kernel_timex *tx);

	int	(*timer_create)(struct k_itimer *timer);

	int	(*nsleep)(const clockid_t which_clock, int flags,

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