linux-kernel - [tip: timers/core] alarmtimer: Remove dead return value in clock2alarm()

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Message-ID: <174599774083.22196.5201101258841287355.tip-bot2@tip-bot2>
Date: Wed, 30 Apr 2025 07:22:20 -0000
From: "tip-bot2 for Su Hui" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Su Hui <suhui@...china.com>, Thomas Gleixner <tglx@...utronix.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject:
 [tip: timers/core] alarmtimer: Remove dead return value in clock2alarm()

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     d8ca84d48a2a2d4f6780980743c34b70c49f5844
Gitweb:        https://git.kernel.org/tip/d8ca84d48a2a2d4f6780980743c34b70c49f5844
Author:        Su Hui <suhui@...china.com>
AuthorDate:    Wed, 30 Apr 2025 11:27:33 +08:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 30 Apr 2025 09:06:23 +02:00

alarmtimer: Remove dead return value in clock2alarm()

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

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

Remove the impossible -1 return value, and add a warning to notify about any
future misuse of this function.

Signed-off-by: Su Hui <suhui@...china.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/all/20250430032734.2079290-3-suhui@nfschina.com

---
 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 0ddccdf..621d396 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;
 }
 
 /**