linux-kernel - [PATCH v3 2/3] alarmtimer: remove dead return value in clock2alarm()

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Message-Id: <20250430032734.2079290-3-suhui@nfschina.com>
Date: Wed, 30 Apr 2025 11:27:33 +0800
From: Su Hui <suhui@...china.com>
To: jstultz@...gle.com,
	tglx@...utronix.de,
	sboyd@...nel.org
Cc: Su Hui <suhui@...china.com>,
	linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH v3 2/3] alarmtimer: remove dead return value in clock2alarm()

'clockid' only can be ALARM_REALTIME and ALARM_BOOTTIME. It's impossible
to return -1 and callers never check the value of -1.

Only alarm_clock_get_timespec(), alarm_clock_get_ktime(),
alarm_timer_create() and alarm_timer_nsleep() call clock2alarm(). These
callers using clockid_to_kclock() to get 'struct k_clock', this ensures
clock2alarm() never returns -1.

Remove the impossible -1 return value, and add a warn to be aware of any
misuse of this function.

Signed-off-by: Su Hui <suhui@...china.com>
---
v3:
 - Add WARN_ON_ONCE to notice any misuse of this function.

v2:
 - No Change.

 kernel/time/alarmtimer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 0ddccdff119a..621d39666e29 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -515,9 +515,9 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
 {
 	if (clockid == CLOCK_REALTIME_ALARM)
 		return ALARM_REALTIME;
-	if (clockid == CLOCK_BOOTTIME_ALARM)
-		return ALARM_BOOTTIME;
-	return -1;
+
+	WARN_ON_ONCE(clockid != CLOCK_BOOTTIME_ALARM);
+	return ALARM_BOOTTIME;
 }
 
 /**
-- 
2.30.2