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posix-clocks: Introduce clock_get_ktime() callback

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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: 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/20191112012724.250792-10-dima@arista.com
This commit is contained in:
Andrei Vagin 2019-11-12 01:26:58 +00:00 committed by Thomas Gleixner
parent 2f58bf909a
commit 9c71a2e8a7
3 changed files with 46 additions and 2 deletions
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19
kernel/time/alarmtimer.c
View File

@ -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,

26
kernel/time/posix-timers.c
View File

@ -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,

3
kernel/time/posix-timers.h
View File

@ -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,