[PATCH 3.16 77/83] alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP

[Ben Hutchings]

3.16.78-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>

commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.

ENOTSUPP is not supposed to be returned to userspace. This was found on an
OpenPower machine, where the RTC does not support set_alarm.

On that system, a clock_nanosleep(CLOCK_REALTIME_ALARM, ...) results in
"524 Unknown error 524"

Replace it with EOPNOTSUPP which results in the expected "95 Operation not
supported" error.

Fixes: 1c6b39ad3f01 (alarmtimers: Return -ENOTSUPP if no RTC device is present)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@xxxxxxxxxxxxx
[ pvorel: backport for v3.16, changes also in alarm_timer_{del,set}(), which
were removed in f2c45807d3992fe0f173f34af9c347d907c31686 in v4.13-rc1 ]
Signed-off-by: Petr Vorel <pvorel@xxxxxxx>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 kernel/time/alarmtimer.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -533,7 +533,7 @@ static int alarm_timer_create(struct k_i
 	struct alarm_base *base;
 
 	if (!alarmtimer_get_rtcdev())
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 
 	if (!capable(CAP_WAKE_ALARM))
 		return -EPERM;
@@ -576,7 +576,7 @@ static void alarm_timer_get(struct k_iti
 static int alarm_timer_del(struct k_itimer *timr)
 {
 	if (!rtcdev)
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 
 	if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 		return TIMER_RETRY;
@@ -600,7 +600,7 @@ static int alarm_timer_set(struct k_itim
 	ktime_t exp;
 
 	if (!rtcdev)
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 
 	if (flags & ~TIMER_ABSTIME)
 		return -EINVAL;
@@ -761,7 +761,7 @@ static int alarm_timer_nsleep(const cloc
 	struct restart_block *restart;
 
 	if (!alarmtimer_get_rtcdev())
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 
 	if (flags & ~TIMER_ABSTIME)
 		return -EINVAL;