posix-timers: Make nanosleep timespec argument const

No nanosleep implementation modifies the rqtp argument. Mark is const.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>

include/linux/hrtimer.h

@@ -454,7 +454,7 @@ static inline u64 hrtimer_forward_now(struct hrtimer *timer,
 /* Precise sleep: */
 
 extern int nanosleep_copyout(struct restart_block *, struct timespec *);
-extern long hrtimer_nanosleep(struct timespec64 *rqtp,
+extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
 			      const enum hrtimer_mode mode,
 			      const clockid_t clockid);
 

kernel/time/alarmtimer.c

@@ -753,7 +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)
+			      const struct timespec64 *tsreq)
 {
 	enum  alarmtimer_type type = clock2alarm(which_clock);
 	struct restart_block *restart = &current->restart_block;

kernel/time/hrtimer.c

@@ -1510,7 +1510,7 @@ static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	return ret;
 }
 
-long hrtimer_nanosleep(struct timespec64 *rqtp,
+long hrtimer_nanosleep(const struct timespec64 *rqtp,
 		       const enum hrtimer_mode mode, const clockid_t clockid)
 {
 	struct restart_block *restart;

kernel/time/posix-cpu-timers.c

@@ -1328,7 +1328,7 @@ 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)
+			    const struct timespec64 *rqtp)
 {
 	struct restart_block *restart_block = &current->restart_block;
 	int error;
@@ -1383,7 +1383,7 @@ 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)
+			      const struct timespec64 *rqtp)
 {
 	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
 }

kernel/time/posix-timers.c

@@ -1214,9 +1214,9 @@ COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
  * nanosleep for monotonic and realtime clocks
  */
 static int common_nsleep(const clockid_t which_clock, int flags,
-			 struct timespec64 *tsave)
+			 const struct timespec64 *rqtp)
 {
-	return hrtimer_nanosleep(tsave, flags & TIMER_ABSTIME ?
+	return hrtimer_nanosleep(rqtp, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
 }

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 *);
+			  const struct timespec64 *);
 	int	(*timer_set)(struct k_itimer *timr, int flags,
 			     struct itimerspec64 *new_setting,
 			     struct itimerspec64 *old_setting);