2021-05-11 01:46:29

by Alexandre Belloni

Subject: [PATCH v2] alarmtimer: check RTC features instead of ops

RTC drivers used to leave .set_alarm() NULL in order to signal the RTC
device doesn't support alarms. The drivers are now clearing the
RTC_FEATURE_ALARM bit for that purpose in order to keep the rtc_class_ops
structure const. So now, .set_alarm() is set unconditionally and this
possibly causes the alarmtimer code to select an RTC device that doesn't
support alarms.

Test RTC_FEATURE_ALARM instead of relying on ops->set_alarm to determine
whether alarms are available.

Fixes: 7ae41220ef58 ("rtc: introduce features bitfield")
Signed-off-by: Alexandre Belloni <[email protected]>
---
kernel/time/alarmtimer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index bea9d08b1698..5897828b9d7e 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -92,7 +92,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
if (rtcdev)
return -EBUSY;

- if (!rtc->ops->set_alarm)
+ if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
return -1;
if (!device_may_wakeup(rtc->dev.parent))
return -1;
--
2.31.1

2021-05-11 19:35:11

by tip-bot2 for Alexey Makhalov

Subject: [tip: timers/urgent] alarmtimer: Check RTC features instead of ops

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

Commit-ID: e09784a8a751e539dffc94d43bc917b0ac1e934a
Gitweb: https://git.kernel.org/tip/e09784a8a751e539dffc94d43bc917b0ac1e934a
Author: Alexandre Belloni <[email protected]>
AuthorDate: Tue, 11 May 2021 03:45:16 +02:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Tue, 11 May 2021 21:28:04 +02:00

alarmtimer: Check RTC features instead of ops

RTC drivers used to leave .set_alarm() NULL in order to signal the RTC
device doesn't support alarms. The drivers are now clearing the
RTC_FEATURE_ALARM bit for that purpose in order to keep the rtc_class_ops
structure const. So now, .set_alarm() is set unconditionally and this
possibly causes the alarmtimer code to select an RTC device that doesn't
support alarms.

Test RTC_FEATURE_ALARM instead of relying on ops->set_alarm to determine
whether alarms are available.

Fixes: 7ae41220ef58 ("rtc: introduce features bitfield")
Signed-off-by: Alexandre Belloni <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]

---
kernel/time/alarmtimer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index bea9d08..5897828 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -92,7 +92,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
if (rtcdev)
return -EBUSY;

- if (!rtc->ops->set_alarm)
+ if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
return -1;
if (!device_may_wakeup(rtc->dev.parent))
return -1;