posix-timers: Store rmtp into restart_block in sys_clock_nanosleep()

... instead of doing that in every ->nsleep() instance
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-5-viro@ZenIV.linux.org.uk

kernel/time/alarmtimer.c

@@ -753,8 +753,7 @@ static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
  * Handles clock_nanosleep calls against _ALARM clockids
  */
 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
-			      struct timespec64 *tsreq,
-			      struct timespec __user *rmtp)
+			      struct timespec64 *tsreq)
 {
 	enum  alarmtimer_type type = clock2alarm(which_clock);
 	struct restart_block *restart = &current->restart_block;
@@ -762,11 +761,6 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 	ktime_t exp;
 	int ret = 0;
 
-	if (flags & TIMER_ABSTIME)
-		rmtp = NULL;
-
-	restart->nanosleep.rmtp = rmtp;
-
 	if (!alarmtimer_get_rtcdev())
 		return -ENOTSUPP;
 

kernel/time/posix-cpu-timers.c

@@ -1328,16 +1328,11 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
 
 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
-			    struct timespec64 *rqtp, struct timespec __user *rmtp)
+			    struct timespec64 *rqtp)
 {
 	struct restart_block *restart_block = &current->restart_block;
 	int error;
 
-	if (flags & TIMER_ABSTIME)
-		rmtp = NULL;
-
-	restart_block->nanosleep.rmtp = rmtp;
-
 	/*
 	 * Diagnose required errors first.
 	 */
@@ -1388,10 +1383,9 @@ static int process_cpu_timer_create(struct k_itimer *timer)
 	return posix_cpu_timer_create(timer);
 }
 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
-			      struct timespec64 *rqtp,
-			      struct timespec __user *rmtp)
+			      struct timespec64 *rqtp)
 {
-	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
+	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
 }
 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
 {

kernel/time/posix-timers.c

@@ -1041,11 +1041,8 @@ SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
  * nanosleep for monotonic and realtime clocks
  */
 static int common_nsleep(const clockid_t which_clock, int flags,
-			 struct timespec64 *tsave, struct timespec __user *rmtp)
+			 struct timespec64 *tsave)
 {
-	if (flags & TIMER_ABSTIME)
-		rmtp = NULL;
-	current->restart_block.nanosleep.rmtp = rmtp;
 	return hrtimer_nanosleep(tsave, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
@@ -1070,8 +1067,11 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 	t64 = timespec_to_timespec64(t);
 	if (!timespec64_valid(&t64))
 		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.nanosleep.rmtp = rmtp;
 
-	return kc->nsleep(which_clock, flags, &t64, rmtp);
+	return kc->nsleep(which_clock, flags, &t64);
 }
 
 /*

kernel/time/posix-timers.h

@@ -10,7 +10,7 @@ struct k_clock {
 	int	(*clock_adj)(const clockid_t which_clock, struct timex *tx);
 	int	(*timer_create)(struct k_itimer *timer);
 	int	(*nsleep)(const clockid_t which_clock, int flags,
-			  struct timespec64 *, struct timespec __user *);
+			  struct timespec64 *);
 	long	(*nsleep_restart)(struct restart_block *restart_block);
 	int	(*timer_set)(struct k_itimer *timr, int flags,
 			     struct itimerspec64 *new_setting,