alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP

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@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@canonical.com
[ 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@suse.cz>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 8c65c236f26a37c75f02b1116a1245249e1381ee..c3fc699868504314e453c223b8e3102ec8237fa8 100644 (file)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -533,7 +533,7 @@ static int alarm_timer_create(struct k_itimer *new_timer)
        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_itimer *timr,
 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_itimer *timr, int flags,
        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 clockid_t which_clock, int flags,
        struct restart_block *restart;
 
        if (!alarmtimer_get_rtcdev())
-               return -ENOTSUPP;
+               return -EOPNOTSUPP;
 
        if (flags & ~TIMER_ABSTIME)
                return -EINVAL;