[PATCH 4.4 87/99] alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP

[Greg Kroah-Hartman]

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>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/time/alarmtimer.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -530,7 +530,7 @@ 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;
@@ -759,7 +759,7 @@ 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;