posix-clocks: Remove interval timer facility and mmap/fasync callbacks

The only user of this facility is ptp_clock, which does not implement any of
those functions.

Remove them to prevent accidental users. Especially the interval timer
interfaces are now more or less impossible to implement because the
necessary infrastructure has been confined to the core code. Aside of that
it's really complex to make these callbacks implemented according to spec
as the alarm timer implementation demonstrates. If at all then a nanosleep
callback might be a reasonable extension. For now keep just what ptp_clock
needs.

Signed-off-by: Thomas Gleixner <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: John Stultz <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]

include/linux/posix-clock.h

···
  * @clock_gettime:  Read the current time
  * @clock_getres:   Get the clock resolution
  * @clock_settime:  Set the current time value
- * @timer_create:   Create a new timer
- * @timer_delete:   Remove a previously created timer
- * @timer_gettime:  Get remaining time and interval of a timer
- * @timer_settime: Set a timer's initial expiration and interval
- * @fasync:         Optional character device fasync method
- * @mmap:           Optional character device mmap method
  * @open:           Optional character device open method
  * @release:        Optional character device release method
  * @ioctl:          Optional character device ioctl method
···
 	int  (*clock_settime)(struct posix_clock *pc,
 			      const struct timespec64 *ts);
 
-	int  (*timer_create) (struct posix_clock *pc, struct k_itimer *kit);
-
-	int  (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit);
-
-	void (*timer_gettime)(struct posix_clock *pc,
-			      struct k_itimer *kit, struct itimerspec64 *tsp);
-
-	int  (*timer_settime)(struct posix_clock *pc,
-			      struct k_itimer *kit, int flags,
-			      struct itimerspec64 *tsp, struct itimerspec64 *old);
 	/*
 	 * Optional character device methods:
 	 */
-	int     (*fasync)  (struct posix_clock *pc,
-			    int fd, struct file *file, int on);
-
 	long    (*ioctl)   (struct posix_clock *pc,
 			    unsigned int cmd, unsigned long arg);
-
-	int     (*mmap)    (struct posix_clock *pc,
-			    struct vm_area_struct *vma);
 
 	int     (*open)    (struct posix_clock *pc, fmode_t f_mode);
 

kernel/time/posix-clock.c

···
 	return result;
 }
 
-static int posix_clock_fasync(int fd, struct file *fp, int on)
-{
-	struct posix_clock *clk = get_posix_clock(fp);
-	int err = 0;
-
-	if (!clk)
-		return -ENODEV;
-
-	if (clk->ops.fasync)
-		err = clk->ops.fasync(clk, fd, fp, on);
-
-	put_posix_clock(clk);
-
-	return err;
-}
-
-static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
-{
-	struct posix_clock *clk = get_posix_clock(fp);
-	int err = -ENODEV;
-
-	if (!clk)
-		return -ENODEV;
-
-	if (clk->ops.mmap)
-		err = clk->ops.mmap(clk, vma);
-
-	put_posix_clock(clk);
-
-	return err;
-}
-
 static long posix_clock_ioctl(struct file *fp,
 			      unsigned int cmd, unsigned long arg)
 {
···
 	.unlocked_ioctl	= posix_clock_ioctl,
 	.open		= posix_clock_open,
 	.release	= posix_clock_release,
-	.fasync		= posix_clock_fasync,
-	.mmap		= posix_clock_mmap,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= posix_clock_compat_ioctl,
 #endif
···
 	return err;
 }
 
-static int pc_timer_create(struct k_itimer *kit)
-{
-	clockid_t id = kit->it_clock;
-	struct posix_clock_desc cd;
-	int err;
-
-	err = get_clock_desc(id, &cd);
-	if (err)
-		return err;
-
-	if (cd.clk->ops.timer_create)
-		err = cd.clk->ops.timer_create(cd.clk, kit);
-	else
-		err = -EOPNOTSUPP;
-
-	put_clock_desc(&cd);
-
-	return err;
-}
-
-static int pc_timer_delete(struct k_itimer *kit)
-{
-	clockid_t id = kit->it_clock;
-	struct posix_clock_desc cd;
-	int err;
-
-	err = get_clock_desc(id, &cd);
-	if (err)
-		return err;
-
-	if (cd.clk->ops.timer_delete)
-		err = cd.clk->ops.timer_delete(cd.clk, kit);
-	else
-		err = -EOPNOTSUPP;
-
-	put_clock_desc(&cd);
-
-	return err;
-}
-
-static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec64 *ts)
-{
-	clockid_t id = kit->it_clock;
-	struct posix_clock_desc cd;
-
-	if (get_clock_desc(id, &cd))
-		return;
-
-	if (cd.clk->ops.timer_gettime)
-		cd.clk->ops.timer_gettime(cd.clk, kit, ts);
-
-	put_clock_desc(&cd);
-}
-
-static int pc_timer_settime(struct k_itimer *kit, int flags,
-			    struct itimerspec64 *ts, struct itimerspec64 *old)
-{
-	clockid_t id = kit->it_clock;
-	struct posix_clock_desc cd;
-	int err;
-
-	err = get_clock_desc(id, &cd);
-	if (err)
-		return err;
-
-	if (cd.clk->ops.timer_settime)
-		err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
-	else
-		err = -EOPNOTSUPP;
-
-	put_clock_desc(&cd);
-
-	return err;
-}
-
 const struct k_clock clock_posix_dynamic = {
 	.clock_getres	= pc_clock_getres,
 	.clock_set	= pc_clock_settime,
 	.clock_get	= pc_clock_gettime,
 	.clock_adj	= pc_clock_adjtime,
-	.timer_create	= pc_timer_create,
-	.timer_set	= pc_timer_settime,
-	.timer_del	= pc_timer_delete,
-	.timer_get	= pc_timer_gettime,
 };