tick/sched: Fix various kernel-doc warnings

Fix a slew of kernel-doc warnings in tick-sched.c:

  tick-sched.c:650: warning: Function parameter or struct member 'now' not described in 'tick_nohz_update_jiffies'
  tick-sched.c:741: warning: No description found for return value of 'get_cpu_idle_time_us'
  tick-sched.c:767: warning: No description found for return value of 'get_cpu_iowait_time_us'
  tick-sched.c:1210: warning: No description found for return value of 'tick_nohz_idle_got_tick'
  tick-sched.c:1228: warning: No description found for return value of 'tick_nohz_get_next_hrtimer'
  tick-sched.c:1243: warning: No description found for return value of 'tick_nohz_get_sleep_length'
  tick-sched.c:1282: warning: Function parameter or struct member 'cpu' not described in 'tick_nohz_get_idle_calls_cpu'
  tick-sched.c:1282: warning: No description found for return value of 'tick_nohz_get_idle_calls_cpu'
  tick-sched.c:1294: warning: No description found for return value of 'tick_nohz_get_idle_calls'
  tick-sched.c:1577: warning: Function parameter or struct member 'hrtimer' not described in 'tick_setup_sched_timer'
  tick-sched.c:1577: warning: Excess function parameter 'mode' description in 'tick_setup_sched_timer'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240331172652.14086-5-rdunlap@infradead.org

kernel/time/tick-sched.c

@@ -697,6 +697,7 @@ bool tick_nohz_tick_stopped_cpu(int cpu)
 
 /**
  * tick_nohz_update_jiffies - update jiffies when idle was interrupted
+ * @now: current ktime_t
  *
  * Called from interrupt entry when the CPU was idle
  *
@@ -794,7 +795,7 @@ static u64 get_cpu_sleep_time_us(struct tick_sched *ts, ktime_t *sleeptime,
  * This time is measured via accounting rather than sampling,
  * and is as accurate as ktime_get() is.
  *
- * This function returns -1 if NOHZ is not enabled.
+ * Return: -1 if NOHZ is not enabled, else total idle time of the @cpu
  */
 u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
@@ -820,7 +821,7 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
  * This time is measured via accounting rather than sampling,
  * and is as accurate as ktime_get() is.
  *
- * This function returns -1 if NOHZ is not enabled.
+ * Return: -1 if NOHZ is not enabled, else total iowait time of @cpu
  */
 u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
 {
@@ -1287,6 +1288,8 @@ void tick_nohz_irq_exit(void)
 
 /**
  * tick_nohz_idle_got_tick - Check whether or not the tick handler has run
+ *
+ * Return: %true if the tick handler has run, otherwise %false
  */
 bool tick_nohz_idle_got_tick(void)
 {
@@ -1305,6 +1308,8 @@ bool tick_nohz_idle_got_tick(void)
  * stopped, it returns the next hrtimer.
  *
  * Called from power state control code with interrupts disabled
+ *
+ * Return: the next expiration time
  */
 ktime_t tick_nohz_get_next_hrtimer(void)
 {
@@ -1320,6 +1325,8 @@ ktime_t tick_nohz_get_next_hrtimer(void)
  * The return value of this function and/or the value returned by it through the
  * @delta_next pointer can be negative which must be taken into account by its
  * callers.
+ *
+ * Return: the expected length of the current sleep
  */
 ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 {
@@ -1357,8 +1364,11 @@ ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 /**
  * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value
  * for a particular CPU.
+ * @cpu: target CPU number
  *
  * Called from the schedutil frequency scaling governor in scheduler context.
+ *
+ * Return: the current idle calls counter value for @cpu
  */
 unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
 {
@@ -1371,6 +1381,8 @@ unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
  * tick_nohz_get_idle_calls - return the current idle calls counter value
  *
  * Called from the schedutil frequency scaling governor in scheduler context.
+ *
+ * Return: the current idle calls counter value for the current CPU
  */
 unsigned long tick_nohz_get_idle_calls(void)
 {
@@ -1559,7 +1571,7 @@ early_param("skew_tick", skew_tick);
 
 /**
  * tick_setup_sched_timer - setup the tick emulation timer
- * @mode: tick_nohz_mode to setup for
+ * @hrtimer: whether to use the hrtimer or not
  */
 void tick_setup_sched_timer(bool hrtimer)
 {