linux-kernel - [patch V3 17/51] posix-timers: Retrieve interval in common timer

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Message-ID: <20240610164026.552899255@linutronix.de>
Date: Mon, 10 Jun 2024 18:42:26 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@...utronix.de>,
 Frederic Weisbecker <frederic@...nel.org>,
 John Stultz <jstultz@...gle.com>,
 Peter Zijlstra <peterz@...radead.org>,
 Ingo Molnar <mingo@...nel.org>,
 Stephen Boyd <sboyd@...nel.org>,
 Eric Biederman <ebiederm@...ssion.com>,
 Oleg Nesterov <oleg@...hat.com>
Subject: [patch V3 17/51] posix-timers: Retrieve interval in common
 timer_settime() code

No point in doing this all over the place.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
V2: Removed the timer_gettime() part - Frederic
---
 kernel/time/posix-cpu-timers.c |   10 ++--------
 kernel/time/posix-timers.c     |    5 ++++-
 2 files changed, 6 insertions(+), 9 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -622,8 +622,8 @@ static int posix_cpu_timer_set(struct k_
 {
 	bool sigev_none = timer->it_sigev_notify == SIGEV_NONE;
 	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
-	u64 old_expires, new_expires, old_incr, now;
 	struct cpu_timer *ctmr = &timer->it.cpu;
+	u64 old_expires, new_expires, now;
 	struct sighand_struct *sighand;
 	struct task_struct *p;
 	unsigned long flags;
@@ -660,10 +660,7 @@ static int posix_cpu_timer_set(struct k_
 		return -ESRCH;
 	}
 
-	/*
-	 * Disarm any old timer after extracting its expiry time.
-	 */
-	old_incr = timer->it_interval;
+	/* Retrieve the current expiry time before disarming the timer */
 	old_expires = cpu_timer_getexpires(ctmr);
 
 	if (unlikely(timer->it.cpu.firing)) {
@@ -742,9 +739,6 @@ static int posix_cpu_timer_set(struct k_
 		cpu_timer_fire(timer);
 out:
 	rcu_read_unlock();
-	if (old)
-		old->it_interval = ns_to_timespec64(old_incr);
-
 	return ret;
 }
 
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -904,7 +904,7 @@ static int do_timer_settime(timer_t time
 	const struct k_clock *kc;
 	struct k_itimer *timr;
 	unsigned long flags;
-	int error = 0;
+	int error;
 
 	if (!timespec64_valid(&new_spec64->it_interval) ||
 	    !timespec64_valid(&new_spec64->it_value))
@@ -918,6 +918,9 @@ static int do_timer_settime(timer_t time
 	if (!timr)
 		return -EINVAL;
 
+	if (old_spec64)
+		old_spec64->it_interval = ktime_to_timespec64(timr->it_interval);
+
 	kc = timr->kclock;
 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
 		error = -EINVAL;