cpu/hotplug: Eliminate all kernel-doc warnings

kernel/cpu.c:57: warning: cannot understand function prototype: 'struct cpuhp_cpu_state '
kernel/cpu.c:115: warning: cannot understand function prototype: 'struct cpuhp_step '
kernel/cpu.c:146: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * cpuhp_invoke_callback _ Invoke the callbacks for a given state
kernel/cpu.c:75: warning: Function parameter or member 'fail' not described in 'cpuhp_cpu_state'
kernel/cpu.c:75: warning: Function parameter or member 'cpu' not described in 'cpuhp_cpu_state'
kernel/cpu.c:75: warning: Function parameter or member 'node' not described in 'cpuhp_cpu_state'
kernel/cpu.c:75: warning: Function parameter or member 'last' not described in 'cpuhp_cpu_state'
kernel/cpu.c:130: warning: Function parameter or member 'list' not described in 'cpuhp_step'
kernel/cpu.c:130: warning: Function parameter or member 'multi_instance' not described in 'cpuhp_step'
kernel/cpu.c:158: warning: No description found for return value of 'cpuhp_invoke_callback'
kernel/cpu.c:1188: warning: No description found for return value of 'cpu_device_down'
kernel/cpu.c:1400: warning: No description found for return value of 'cpu_device_up'
kernel/cpu.c:1425: warning: No description found for return value of 'bringup_hibernate_cpu'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210809223825.24512-1-rdunlap@infradead.org

kernel/cpu.c

@@ -41,14 +41,19 @@
 #include "smpboot.h"
 
 /**
- * cpuhp_cpu_state - Per cpu hotplug state storage
+ * struct cpuhp_cpu_state - Per cpu hotplug state storage
  * @state:	The current cpu state
  * @target:	The target state
+ * @fail:	Current CPU hotplug callback state
  * @thread:	Pointer to the hotplug thread
  * @should_run:	Thread should execute
  * @rollback:	Perform a rollback
  * @single:	Single callback invocation
  * @bringup:	Single callback bringup or teardown selector
+ * @cpu:	CPU number
+ * @node:	Remote CPU node; for multi-instance, do a
+ *		single entry callback for install/remove
+ * @last:	For multi-instance rollback, remember how far we got
  * @cb_state:	The state for a single callback (install/uninstall)
  * @result:	Result of the operation
  * @done_up:	Signal completion to the issuer of the task for cpu-up
@@ -106,11 +111,12 @@ static inline void cpuhp_lock_release(bool bringup) { }
 #endif
 
 /**
- * cpuhp_step - Hotplug state machine step
+ * struct cpuhp_step - Hotplug state machine step
  * @name:	Name of the step
  * @startup:	Startup function of the step
  * @teardown:	Teardown function of the step
  * @cant_stop:	Bringup/teardown can't be stopped at this step
+ * @multi_instance:	State has multiple instances which get added afterwards
  */
 struct cpuhp_step {
 	const char		*name;
@@ -124,7 +130,9 @@ struct cpuhp_step {
 		int		(*multi)(unsigned int cpu,
 					 struct hlist_node *node);
 	} teardown;
+	/* private: */
 	struct hlist_head	list;
+	/* public: */
 	bool			cant_stop;
 	bool			multi_instance;
 };
@@ -143,7 +151,7 @@ static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step)
 }
 
 /**
- * cpuhp_invoke_callback _ Invoke the callbacks for a given state
+ * cpuhp_invoke_callback - Invoke the callbacks for a given state
  * @cpu:	The cpu for which the callback should be invoked
  * @state:	The state to do callbacks for
  * @bringup:	True if the bringup callback should be invoked
@@ -151,6 +159,8 @@ static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step)
  * @lastp:	For multi-instance rollback, remember how far we got
  *
  * Called from cpu hotplug and from the state register machinery.
+ *
+ * Return: %0 on success or a negative errno code
  */
 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
 				 bool bringup, struct hlist_node *node,
@@ -1183,6 +1193,8 @@ static int cpu_down(unsigned int cpu, enum cpuhp_state target)
  * This function is meant to be used by device core cpu subsystem only.
  *
  * Other subsystems should use remove_cpu() instead.
+ *
+ * Return: %0 on success or a negative errno code
  */
 int cpu_device_down(struct device *dev)
 {
@@ -1395,6 +1407,8 @@ out:
  * This function is meant to be used by device core cpu subsystem only.
  *
  * Other subsystems should use add_cpu() instead.
+ *
+ * Return: %0 on success or a negative errno code
  */
 int cpu_device_up(struct device *dev)
 {
@@ -1420,6 +1434,8 @@ EXPORT_SYMBOL_GPL(add_cpu);
  * On some architectures like arm64, we can hibernate on any CPU, but on
  * wake up the CPU we hibernated on might be offline as a side effect of
  * using maxcpus= for example.
+ *
+ * Return: %0 on success or a negative errno code
  */
 int bringup_hibernate_cpu(unsigned int sleep_cpu)
 {
@@ -1985,9 +2001,9 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
  *			added afterwards.
  *
  * The caller needs to hold cpus read locked while calling this function.
- * Returns:
+ * Return:
  *   On success:
- *      Positive state number if @state is CPUHP_AP_ONLINE_DYN
+ *      Positive state number if @state is CPUHP_AP_ONLINE_DYN;
  *      0 for all other states
  *   On failure: proper (negative) error code
  */