posix-timers: Split release_posix_timers()

release_posix_timers() is called for cleaning up both hashed and unhashed
timers. The cases are differentiated by an argument and the usage is
hideous.

Seperate the actual free path out and use it for unhashed timers. Provide a
function for hashed timers.

No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230425183313.301432503@linutronix.de

kernel/time/posix-timers.c

@@ -466,20 +466,21 @@ static void k_itimer_rcu_free(struct rcu_head *head)
 	kmem_cache_free(posix_timers_cache, tmr);
 }
 
-#define IT_ID_SET	1
-#define IT_ID_NOT_SET	0
-static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
-{
-	if (it_id_set) {
-		spin_lock(&hash_lock, flags);
-		hlist_del_rcu(&tmr->t_hash);
-		spin_unlock(&hash_lock, flags);
-	}
+static void posix_timer_free(struct k_itimer *tmr)
+{
 	put_pid(tmr->it_pid);
 	sigqueue_free(tmr->sigq);
 	call_rcu(&tmr->rcu, k_itimer_rcu_free);
 }
 
+static void posix_timer_unhash_and_free(struct k_itimer *tmr)
+{
+	spin_lock(&hash_lock);
+	hlist_del_rcu(&tmr->t_hash);
+	spin_unlock(&hash_lock);
+	posix_timer_free(tmr);
+}
+
 static int common_timer_create(struct k_itimer *new_timer)
 {
 	hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
@@ -493,7 +494,6 @@ static int do_timer_create(clockid_t which_clock, struct sigevent *event,
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct k_itimer *new_timer;
 	int error, new_timer_id;
-	int it_id_set = IT_ID_NOT_SET;
 
 	if (!kc)
 		return -EINVAL;
@@ -513,11 +513,10 @@ static int do_timer_create(clockid_t which_clock, struct sigevent *event,
 	 */
 	new_timer_id = posix_timer_add(new_timer);
 	if (new_timer_id < 0) {
-		error = new_timer_id;
-		goto out;
+		posix_timer_free(new_timer);
+		return new_timer_id;
 	}
 
-	it_id_set = IT_ID_SET;
 	new_timer->it_id = (timer_t) new_timer_id;
 	new_timer->it_clock = which_clock;
 	new_timer->kclock = kc;
@@ -569,7 +568,7 @@ static int do_timer_create(clockid_t which_clock, struct sigevent *event,
 	 * new_timer after the unlock call.
 	 */
 out:
-	release_posix_timer(new_timer, it_id_set);
+	posix_timer_unhash_and_free(new_timer);
 	return error;
 }
 
@@ -1057,7 +1056,7 @@ SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
 	WRITE_ONCE(timer->it_signal, NULL);
 
 	unlock_timer(timer, flags);
-	release_posix_timer(timer, IT_ID_SET);
+	posix_timer_unhash_and_free(timer);
 	return 0;
 }
 
@@ -1109,7 +1108,7 @@ static void itimer_delete(struct k_itimer *timer)
 	WRITE_ONCE(timer->it_signal, NULL);
 
 	spin_unlock_irqrestore(&timer->it_lock, flags);
-	release_posix_timer(timer, IT_ID_SET);
+	posix_timer_unhash_and_free(timer);
 }
 
 /*