linux-kernel - [PATCH v2 3/3] alarmtimer: switch some spin_{lock,unlock}

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Message-Id: <20250427113529.1473800-4-suhui@nfschina.com>
Date: Sun, 27 Apr 2025 19:35:30 +0800
From: Su Hui <suhui@...china.com>
To: jstultz@...gle.com,
	tglx@...utronix.de,
	sboyd@...nel.org
Cc: Su Hui <suhui@...china.com>,
	dan.carpenter@...aro.org,
	linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH v2 3/3] alarmtimer: switch some spin_{lock,unlock}_irqsave() to guard()

Using guard/scoped_guard() to simplify code. Using guard() to remove
'goto unlock' label is neater especially.

Signed-off-by: Su Hui <suhui@...china.com>
---
v2:
 - Remove some guard() usages acrodding to john's suggestions.

 kernel/time/alarmtimer.c | 56 +++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index e5450a77ada9..90cb59a3e9c2 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -70,12 +70,10 @@ static DEFINE_SPINLOCK(rtcdev_lock);
  */
 struct rtc_device *alarmtimer_get_rtcdev(void)
 {
-	unsigned long flags;
 	struct rtc_device *ret;
 
-	spin_lock_irqsave(&rtcdev_lock, flags);
+	guard(spinlock_irqsave)(&rtcdev_lock);
 	ret = rtcdev;
-	spin_unlock_irqrestore(&rtcdev_lock, flags);
 
 	return ret;
 }
@@ -83,7 +81,6 @@ EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
 
 static int alarmtimer_rtc_add_device(struct device *dev)
 {
-	unsigned long flags;
 	struct rtc_device *rtc = to_rtc_device(dev);
 	struct platform_device *pdev;
 	int ret = 0;
@@ -101,22 +98,21 @@ static int alarmtimer_rtc_add_device(struct device *dev)
 	if (!IS_ERR(pdev))
 		device_init_wakeup(&pdev->dev, true);
 
-	spin_lock_irqsave(&rtcdev_lock, flags);
-	if (!IS_ERR(pdev) && !rtcdev) {
-		if (!try_module_get(rtc->owner)) {
+	scoped_guard(spinlock_irqsave, &rtcdev_lock) {
+		if (!IS_ERR(pdev) && !rtcdev) {
+			if (!try_module_get(rtc->owner)) {
+				ret = -1;
+				break;
+			}
+
+			rtcdev = rtc;
+			/* hold a reference so it doesn't go away */
+			get_device(dev);
+			pdev = NULL;
+		} else {
 			ret = -1;
-			goto unlock;
 		}
-
-		rtcdev = rtc;
-		/* hold a reference so it doesn't go away */
-		get_device(dev);
-		pdev = NULL;
-	} else {
-		ret = -1;
 	}
-unlock:
-	spin_unlock_irqrestore(&rtcdev_lock, flags);
 
 	platform_device_unregister(pdev);
 
@@ -198,7 +194,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 	struct alarm *alarm = container_of(timer, struct alarm, timer);
 	struct alarm_base *base = &alarm_bases[alarm->type];
 
-	scoped_guard (spinlock_irqsave, &base->lock)
+	scoped_guard(spinlock_irqsave, &base->lock)
 		alarmtimer_dequeue(base, alarm);
 
 	if (alarm->function)
@@ -251,9 +247,8 @@ static int alarmtimer_suspend(struct device *dev)
 		struct timerqueue_node *next;
 		ktime_t delta;
 
-		spin_lock_irqsave(&base->lock, flags);
-		next = timerqueue_getnext(&base->timerqueue);
-		spin_unlock_irqrestore(&base->lock, flags);
+		scoped_guard(spinlock_irqsave, &base->lock)
+			next = timerqueue_getnext(&base->timerqueue);
 		if (!next)
 			continue;
 		delta = ktime_sub(next->expires, base->get_ktime());
@@ -381,13 +376,11 @@ EXPORT_SYMBOL_GPL(alarm_start_relative);
 void alarm_restart(struct alarm *alarm)
 {
 	struct alarm_base *base = &alarm_bases[alarm->type];
-	unsigned long flags;
 
-	spin_lock_irqsave(&base->lock, flags);
+	guard(spinlock_irqsave)(&base->lock);
 	hrtimer_set_expires(&alarm->timer, alarm->node.expires);
 	hrtimer_restart(&alarm->timer);
 	alarmtimer_enqueue(base, alarm);
-	spin_unlock_irqrestore(&base->lock, flags);
 }
 EXPORT_SYMBOL_GPL(alarm_restart);
 
@@ -401,14 +394,13 @@ EXPORT_SYMBOL_GPL(alarm_restart);
 int alarm_try_to_cancel(struct alarm *alarm)
 {
 	struct alarm_base *base = &alarm_bases[alarm->type];
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&base->lock, flags);
-	ret = hrtimer_try_to_cancel(&alarm->timer);
-	if (ret >= 0)
-		alarmtimer_dequeue(base, alarm);
-	spin_unlock_irqrestore(&base->lock, flags);
+	scoped_guard(spinlock_irqsave, &base->lock) {
+		ret = hrtimer_try_to_cancel(&alarm->timer);
+		if (ret >= 0)
+			alarmtimer_dequeue(base, alarm);
+	}
 
 	trace_alarmtimer_cancel(alarm, base->get_ktime());
 	return ret;
@@ -479,7 +471,6 @@ EXPORT_SYMBOL_GPL(alarm_forward_now);
 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 {
 	struct alarm_base *base;
-	unsigned long flags;
 	ktime_t delta;
 
 	switch(type) {
@@ -498,13 +489,12 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 
 	delta = ktime_sub(absexp, base->get_ktime());
 
-	spin_lock_irqsave(&freezer_delta_lock, flags);
+	guard(spinlock_irqsave)(&freezer_delta_lock);
 	if (!freezer_delta || (delta < freezer_delta)) {
 		freezer_delta = delta;
 		freezer_expires = absexp;
 		freezer_alarmtype = type;
 	}
-	spin_unlock_irqrestore(&freezer_delta_lock, flags);
 }
 
 /**
-- 
2.30.2