Messages in this thread Patch in this message | | | From | Thomas Gleixner <> | Subject | [patch V2 31/50] posix-timers: Add proper state tracking | Date | Thu, 11 Apr 2024 00:47:06 +0200 (CEST) |
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Right now the state tracking is done by two struct members:
- it_active: A boolean which tracks armed/disarmed state
- it_signal_seq: A sequence counter which is used to invalidate settings and prevent rearming
Replace it_active with it_status and keep properly track about the states in one place.
This allows to reuse it_signal_seq to track reprogramming, disarm and delete operations in order to drop signals which are related to the state previous of those operations.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- include/linux/posix-timers.h | 4 ++-- kernel/time/alarmtimer.c | 2 +- kernel/time/posix-cpu-timers.c | 15 ++++++++------- kernel/time/posix-timers.c | 22 +++++++++++++--------- kernel/time/posix-timers.h | 6 ++++++ 5 files changed, 30 insertions(+), 19 deletions(-)
--- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -147,7 +147,7 @@ static inline void posix_cputimers_init_ * @kclock: Pointer to the k_clock struct handling this timer * @it_clock: The posix timer clock id * @it_id: The posix timer id for identifying the timer - * @it_active: Marker that timer is active + * @it_status: The status of the timer * @it_overrun: The overrun counter for pending signals * @it_overrun_last: The overrun at the time of the last delivered signal * @it_signal_seq: Sequence count to control signal delivery @@ -168,7 +168,7 @@ struct k_itimer { const struct k_clock *kclock; clockid_t it_clock; timer_t it_id; - int it_active; + int it_status; s64 it_overrun; s64 it_overrun_last; unsigned int it_signal_seq; --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -585,7 +585,7 @@ static enum alarmtimer_restart alarm_han */ ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true); ++ptr->it_signal_seq; - ptr->it_active = 1; + ptr->it_status = POSIX_TIMER_ARMED; result = ALARMTIMER_RESTART; } spin_unlock_irqrestore(&ptr->it_lock, flags); --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -453,7 +453,6 @@ static void disarm_timer(struct k_itimer struct cpu_timer *ctmr = &timer->it.cpu; struct posix_cputimer_base *base; - timer->it_active = 0; if (!cpu_timer_dequeue(ctmr)) return; @@ -494,11 +493,12 @@ static int posix_cpu_timer_del(struct k_ */ WARN_ON_ONCE(ctmr->head || timerqueue_node_queued(&ctmr->node)); } else { - if (timer->it.cpu.firing) + if (timer->it.cpu.firing) { ret = TIMER_RETRY; - else + } else { disarm_timer(timer, p); - + timer->it_status = POSIX_TIMER_DISARMED; + } unlock_task_sighand(p, &flags); } @@ -560,7 +560,7 @@ static void arm_timer(struct k_itimer *t struct cpu_timer *ctmr = &timer->it.cpu; u64 newexp = cpu_timer_getexpires(ctmr); - timer->it_active = 1; + timer->it_status = POSIX_TIMER_ARMED; if (!cpu_timer_enqueue(&base->tqhead, ctmr)) return; @@ -586,7 +586,8 @@ static void cpu_timer_fire(struct k_itim { struct cpu_timer *ctmr = &timer->it.cpu; - timer->it_active = 0; + timer->it_status = POSIX_TIMER_DISARMED; + if (unlikely(timer->sigq == NULL)) { /* * This a special case for clock_nanosleep, @@ -671,7 +672,7 @@ static int posix_cpu_timer_set(struct k_ ret = TIMER_RETRY; } else { cpu_timer_dequeue(ctmr); - timer->it_active = 0; + timer->it_status = POSIX_TIMER_DISARMED; } /* --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -272,7 +272,7 @@ bool posixtimer_deliver_signal(struct ke if (timr->it_interval && timr->it_signal_seq == info->si_sys_private) { timr->kclock->timer_rearm(timr); - timr->it_active = 1; + timr->it_status = POSIX_TIMER_ARMED; timr->it_overrun_last = timr->it_overrun; timr->it_overrun = -1LL; ++timr->it_signal_seq; @@ -292,14 +292,17 @@ bool posixtimer_deliver_signal(struct ke int posix_timer_queue_signal(struct k_itimer *timr) { + enum posix_timer_state state = POSIX_TIMER_DISARMED; int ret, si_private = 0; enum pid_type type; lockdep_assert_held(&timr->it_lock); - timr->it_active = 0; - if (timr->it_interval) + if (timr->it_interval) { + state = POSIX_TIMER_REQUEUE_PENDING; si_private = ++timr->it_signal_seq; + } + timr->it_status = state; type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID; ret = send_sigqueue(timr->sigq, timr->it_pid, type, si_private); @@ -367,7 +370,7 @@ static enum hrtimer_restart posix_timer_ timr->it_overrun += hrtimer_forward(timer, now, timr->it_interval); ret = HRTIMER_RESTART; ++timr->it_signal_seq; - timr->it_active = 1; + timr->it_status = POSIX_TIMER_ARMED; } } @@ -647,10 +650,10 @@ void common_timer_get(struct k_itimer *t /* interval timer ? */ if (iv) { cur_setting->it_interval = ktime_to_timespec64(iv); - } else if (!timr->it_active) { + } else if (timr->it_status == POSIX_TIMER_DISARMED) { /* * SIGEV_NONE oneshot timers are never queued and therefore - * timr->it_active is always false. The check below + * timr->it_status is always DISARMED. The check below * vs. remaining time will handle this case. * * For all other timers there is nothing to update here, so @@ -895,7 +898,7 @@ int common_timer_set(struct k_itimer *ti if (kc->timer_try_to_cancel(timr) < 0) return TIMER_RETRY; - timr->it_active = 0; + timr->it_status = POSIX_TIMER_DISARMED; posix_timer_set_common(timr, new_setting); /* Keep timer disarmed when it_value is zero */ @@ -908,7 +911,8 @@ int common_timer_set(struct k_itimer *ti sigev_none = timr->it_sigev_notify == SIGEV_NONE; kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none); - timr->it_active = !sigev_none; + if (!sigev_none) + timr->it_status = POSIX_TIMER_ARMED; return 0; } @@ -1007,7 +1011,7 @@ int common_timer_del(struct k_itimer *ti timer->it_interval = 0; if (kc->timer_try_to_cancel(timer) < 0) return TIMER_RETRY; - timer->it_active = 0; + timer->it_status = POSIX_TIMER_DISARMED; return 0; } --- a/kernel/time/posix-timers.h +++ b/kernel/time/posix-timers.h @@ -1,6 +1,12 @@ /* SPDX-License-Identifier: GPL-2.0 */ #define TIMER_RETRY 1 +enum posix_timer_state { + POSIX_TIMER_DISARMED, + POSIX_TIMER_ARMED, + POSIX_TIMER_REQUEUE_PENDING, +}; + struct k_clock { int (*clock_getres)(const clockid_t which_clock, struct timespec64 *tp);
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