posix-timers: Rename k_itimer:: It_requeue_pending

Prepare for using this struct member to do a proper reprogramming and
deletion accounting so that stale signals can be dropped.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241001083835.611997737@linutronix.de

include/linux/posix-timers.h

@@ -150,8 +150,7 @@ static inline void posix_cputimers_init_work(void) { }
  * @it_active:		Marker that timer is active
  * @it_overrun:		The overrun counter for pending signals
  * @it_overrun_last:	The overrun at the time of the last delivered signal
- * @it_requeue_pending:	Indicator that timer waits for being requeued on
- *			signal delivery
+ * @it_signal_seq:	Sequence count to control signal delivery
  * @it_sigev_notify:	The notify word of sigevent struct for signal delivery
  * @it_interval:	The interval for periodic timers
  * @it_signal:		Pointer to the creators signal struct
@@ -172,7 +171,7 @@ struct k_itimer {
 	int			it_active;
 	s64			it_overrun;
 	s64			it_overrun_last;
-	int			it_requeue_pending;
+	unsigned int		it_signal_seq;
 	int			it_sigev_notify;
 	ktime_t			it_interval;
 	struct signal_struct	*it_signal;

kernel/time/alarmtimer.c

@@ -584,7 +584,7 @@ static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 		 * small intervals cannot starve the system.
 		 */
 		ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
-		++ptr->it_requeue_pending;
+		++ptr->it_signal_seq;
 		ptr->it_active = 1;
 		result = ALARMTIMER_RESTART;
 	}

kernel/time/posix-cpu-timers.c

@@ -608,7 +608,7 @@ static void cpu_timer_fire(struct k_itimer *timer)
 		 * ticking in case the signal is deliverable next time.
 		 */
 		posix_cpu_timer_rearm(timer);
-		++timer->it_requeue_pending;
+		++timer->it_signal_seq;
 	}
 }
 
@@ -745,7 +745,7 @@ static void __posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *i
 	 *  - Timers which expired, but the signal has not yet been
 	 *    delivered
 	 */
-	if (iv && ((timer->it_requeue_pending & REQUEUE_PENDING) || sigev_none))
+	if (iv && ((timer->it_signal_seq & REQUEUE_PENDING) || sigev_none))
 		expires = bump_cpu_timer(timer, now);
 	else
 		expires = cpu_timer_getexpires(&timer->it.cpu);

kernel/time/posix-timers.c

@@ -269,13 +269,13 @@ bool posixtimer_deliver_signal(struct kernel_siginfo *info)
 	if (!timr)
 		goto out;
 
-	if (timr->it_interval && timr->it_requeue_pending == info->si_sys_private) {
+	if (timr->it_interval && timr->it_signal_seq == info->si_sys_private) {
 		timr->kclock->timer_rearm(timr);
 
 		timr->it_active = 1;
 		timr->it_overrun_last = timr->it_overrun;
 		timr->it_overrun = -1LL;
-		++timr->it_requeue_pending;
+		++timr->it_signal_seq;
 
 		info->si_overrun = timer_overrun_to_int(timr, info->si_overrun);
 	}
@@ -299,7 +299,7 @@ int posix_timer_queue_signal(struct k_itimer *timr)
 
 	timr->it_active = 0;
 	if (timr->it_interval)
-		si_private = ++timr->it_requeue_pending;
+		si_private = ++timr->it_signal_seq;
 
 	type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID;
 	ret = send_sigqueue(timr->sigq, timr->it_pid, type, si_private);
@@ -366,7 +366,7 @@ static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
 
 			timr->it_overrun += hrtimer_forward(timer, now, timr->it_interval);
 			ret = HRTIMER_RESTART;
-			++timr->it_requeue_pending;
+			++timr->it_signal_seq;
 			timr->it_active = 1;
 		}
 	}
@@ -660,7 +660,7 @@ void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
 	 * is a SIGEV_NONE timer move the expiry time forward by intervals,
 	 * so expiry is > now.
 	 */
-	if (iv && (timr->it_requeue_pending & REQUEUE_PENDING || sig_none))
+	if (iv && (timr->it_signal_seq & REQUEUE_PENDING || sig_none))
 		timr->it_overrun += kc->timer_forward(timr, now);
 
 	remaining = kc->timer_remaining(timr, now);
@@ -861,7 +861,7 @@ void posix_timer_set_common(struct k_itimer *timer, struct itimerspec64 *new_set
 		timer->it_interval = 0;
 
 	/* Prevent reloading in case there is a signal pending */
-	timer->it_requeue_pending = (timer->it_requeue_pending + 2) & ~REQUEUE_PENDING;
+	timer->it_signal_seq = (timer->it_signal_seq + 2) & ~REQUEUE_PENDING;
 	/* Reset overrun accounting */
 	timer->it_overrun_last = 0;
 	timer->it_overrun = -1LL;