posix-stubs: Use get_timespec64() and put_timespec64()

This is a follow-up to commit 5c499410 ("posix-timers: Use
get_timespec64() and put_timespec64()"), which left two system call using
copy_from_user()/copy_to_user().

Change them as well for consistency.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: y2038@lists.linaro.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Link: https://lkml.kernel.org/r/20171013183009.3442318-1-arnd@arndb.de

kernel/time/posix-stubs.c

@@ -117,8 +117,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 		const struct timespec __user *, rqtp,
 		struct timespec __user *, rmtp)
 {
-	struct timespec64 t64;
-	struct timespec t;
+	struct timespec64 t;
 
 	switch (which_clock) {
 	case CLOCK_REALTIME:
@@ -129,16 +128,15 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 		return -EINVAL;
 	}
 
-	if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
+	if (get_timespec64(&t, rqtp))
 		return -EFAULT;
-	t64 = timespec_to_timespec64(t);
-	if (!timespec64_valid(&t64))
+	if (!timespec64_valid(&t))
 		return -EINVAL;
 	if (flags & TIMER_ABSTIME)
 		rmtp = NULL;
 	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
 	current->restart_block.nanosleep.rmtp = rmtp;
-	return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
+	return hrtimer_nanosleep(&t, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
 }
@@ -203,8 +201,7 @@ COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
 		       struct compat_timespec __user *, rqtp,
 		       struct compat_timespec __user *, rmtp)
 {
-	struct timespec64 t64;
-	struct timespec t;
+	struct timespec64 t;
 
 	switch (which_clock) {
 	case CLOCK_REALTIME:
@@ -215,16 +212,15 @@ COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
 		return -EINVAL;
 	}
 
-	if (compat_get_timespec(&t, rqtp))
+	if (compat_get_timespec64(&t, rqtp))
 		return -EFAULT;
-	t64 = timespec_to_timespec64(t);
-	if (!timespec64_valid(&t64))
+	if (!timespec64_valid(&t))
 		return -EINVAL;
 	if (flags & TIMER_ABSTIME)
 		rmtp = NULL;
 	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
 	current->restart_block.nanosleep.compat_rmtp = rmtp;
-	return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
+	return hrtimer_nanosleep(&t, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
 }