[PATCH 04/28] PM: QoS: Clean up pm_qos_update_target() and pm_qos_update_flags()

Rafael J. Wysocki
2020-02-11T23:39:43Z

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

Clean up the pm_qos_update_target() function:
* Update its kerneldoc comment.
* Drop the redundant ret local variable from it.
* Reorder definitions of local variables in it.
* Update a comment in it.

Also update the kerneldoc comment of pm_qos_update_flags() (e.g.
notifiers are not called by it any more) and add one emtpy line
to its body (for more visual clarity).

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
kernel/power/qos.c | 56 ++++++++++++++++++++++++++++--------------------------
1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index a6be7faa1974..6a36809d6160 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -129,24 +129,30 @@ static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
}

/**
- * pm_qos_update_target - manages the constraints list and calls the notifiers
- * if needed
- * @c: constraints data struct
- * @node: request to add to the list, to update or to remove
- * @action: action to take on the constraints list
- * @value: value of the request to add or update
+ * pm_qos_update_target - Update a list of PM QoS constraint requests.
+ * @c: List of PM QoS requests.
+ * @node: Target list entry.
+ * @action: Action to carry out (add, update or remove).
+ * @value: New request value for the target list entry.
*
- * This function returns 1 if the aggregated constraint value has changed, 0
- * otherwise.
+ * Update the given list of PM QoS constraint requests, @c, by carrying an
+ * @action involving the @node list entry and @value on it.
+ *
+ * The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node
+ * and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store
+ * @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove
+ * @node from the list, ignore @value).
+ *
+ * Return: 1 if the aggregate constraint value has changed, 0 otherwise.
*/
int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
enum pm_qos_req_action action, int value)
{
- unsigned long flags;
int prev_value, curr_value, new_value;
- int ret;
+ unsigned long flags;

spin_lock_irqsave(&pm_qos_lock, flags);
+
prev_value = pm_qos_get_value(c);
if (value == PM_QOS_DEFAULT_VALUE)
new_value = c->default_value;
@@ -159,9 +165,8 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
break;
case PM_QOS_UPDATE_REQ:
/*
- * to change the list, we atomically remove, reinit
- * with new value and add, then see if the extremal
- * changed
+ * To change the list, atomically remove, reinit with new value
+ * and add, then see if the aggregate has changed.
*/
plist_del(node, &c->list);
/* fall through */
@@ -180,16 +185,14 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
spin_unlock_irqrestore(&pm_qos_lock, flags);

trace_pm_qos_update_target(action, prev_value, curr_value);
- if (prev_value != curr_value) {
- ret = 1;
- if (c->notifiers)
- blocking_notifier_call_chain(c->notifiers,
- (unsigned long)curr_value,
- NULL);
- } else {
- ret = 0;
- }
- return ret;
+
+ if (prev_value == curr_value)
+ return 0;
+
+ if (c->notifiers)
+ blocking_notifier_call_chain(c->notifiers, curr_value, NULL);
+
+ return 1;
}

/**
@@ -211,14 +214,12 @@ static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf,

/**
* pm_qos_update_flags - Update a set of PM QoS flags.
- * @pqf: Set of flags to update.
+ * @pqf: Set of PM QoS flags to update.
* @req: Request to add to the set, to modify, or to remove from the set.
* @action: Action to take on the set.
* @val: Value of the request to add or modify.
*
- * Update the given set of PM QoS flags and call notifiers if the aggregate
- * value has changed. Returns 1 if the aggregate constraint value has changed,
- * 0 otherwise.
+ * Return: 1 if the aggregate constraint value has changed, 0 otherwise.
*/
bool pm_qos_update_flags(struct pm_qos_flags *pqf,
struct pm_qos_flags_request *req,
@@ -254,6 +255,7 @@ bool pm_qos_update_flags(struct pm_qos_flags *pqf,
spin_unlock_irqrestore(&pm_qos_lock, irqflags);

trace_pm_qos_update_flags(action, prev_value, curr_value);
+
return prev_value != curr_value;
}

--
2.16.4