alarmtimer: return EINVAL instead of ENOTSUPP if rtcdev doesn't exist
authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Mon, 14 Oct 2013 21:33:16 +0000 (17:33 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 4 Dec 2013 18:55:49 +0000 (10:55 -0800)
commit4501cfd0e3a1c06e5539c9f806866f8408232393
tree77ec888365af95de5db67d17d88e2e4ec6d5f882
parent9dfd005a3f4e1c648cb4aa1dc70604bb370c5e7b
alarmtimer: return EINVAL instead of ENOTSUPP if rtcdev doesn't exist

commit 98d6f4dd84a134d942827584a3c5f67ffd8ec35f upstream.

Fedora Ruby maintainer reported latest Ruby doesn't work on Fedora Rawhide
on ARM. (http://bugs.ruby-lang.org/issues/9008)

Because of, commit 1c6b39ad3f (alarmtimers: Return -ENOTSUPP if no
RTC device is present) intruduced to return ENOTSUPP when
clock_get{time,res} can't find a RTC device. However this is incorrect.

First, ENOTSUPP isn't exported to userland (ENOTSUP or EOPNOTSUP are the
closest userland equivlents).

Second, Posix and Linux man pages agree that clock_gettime and
clock_getres should return EINVAL if clk_id argument is invalid.
While the arugment that the clockid is valid, but just not supported
on this hardware could be made, this is just a technicality that
doesn't help userspace applicaitons, and only complicates error
handling.

Thus, this patch changes the code to use EINVAL.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: Vit Ondruch <v.ondruch@tiscali.cz>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
[jstultz: Tweaks to commit message to include full rational]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/time/alarmtimer.c