[PATCH v1 06/10] devfreq: Add module owner to devfreq governor

[Jie Zhan]

Add an 'owner' member to struct devfreq_governor, such that we can find
the module that holds the governor code when it's compiled as a kernel
module.  This allows the devfreq core to properly manage the lifecycle
of governors.

Update devfreq_add_governor() and devm_devfreq_add_governor() to
automatically set 'owner' to THIS_MODULE via helper macros.

This is a prerequisite for implementing governor reference counting
to prevent module unloading while a governor is in use.

Signed-off-by: Jie Zhan <zhanjie9 at hisilicon.com>
---
 drivers/devfreq/devfreq.c        | 26 +++++++++-----------------
 include/linux/devfreq-governor.h | 26 +++++++++++++++++++++++---
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 7e71e8c76303..9b078458d129 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1293,11 +1293,8 @@ void devfreq_resume(void)
 	mutex_unlock(&devfreq_list_lock);
 }
 
-/**
- * devfreq_add_governor() - Add devfreq governor
- * @governor:	the devfreq governor to be added
- */
-int devfreq_add_governor(struct devfreq_governor *governor)
+int __devfreq_add_governor(struct devfreq_governor *governor,
+			   struct module *mod)
 {
 	struct devfreq_governor *g;
 
@@ -1313,38 +1310,33 @@ int devfreq_add_governor(struct devfreq_governor *governor)
 		return -EINVAL;
 	}
 
+	governor->owner = mod;
 	scoped_guard(mutex, &devfreq_gov_lock)
 		list_add(&governor->node, &devfreq_governor_list);
 
 	return 0;
 }
-EXPORT_SYMBOL(devfreq_add_governor);
+EXPORT_SYMBOL(__devfreq_add_governor);
 
 static void devm_devfreq_remove_governor(void *governor)
 {
 	WARN_ON(devfreq_remove_governor(governor));
 }
 
-/**
- * devm_devfreq_add_governor() - Add devfreq governor
- * @dev:	device which adds devfreq governor
- * @governor:	the devfreq governor to be added
- *
- * This is a resource-managed variant of devfreq_add_governor().
- */
-int devm_devfreq_add_governor(struct device *dev,
-			      struct devfreq_governor *governor)
+int __devm_devfreq_add_governor(struct device *dev,
+				struct devfreq_governor *governor,
+				struct module *mod)
 {
 	int err;
 
-	err = devfreq_add_governor(governor);
+	err = __devfreq_add_governor(governor, mod);
 	if (err)
 		return err;
 
 	return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
 					governor);
 }
-EXPORT_SYMBOL(devm_devfreq_add_governor);
+EXPORT_SYMBOL(__devm_devfreq_add_governor);
 
 /**
  * devfreq_remove_governor() - Remove devfreq feature from a device.
diff --git a/include/linux/devfreq-governor.h b/include/linux/devfreq-governor.h
index dfdd0160a29f..1c4ff57e24de 100644
--- a/include/linux/devfreq-governor.h
+++ b/include/linux/devfreq-governor.h
@@ -12,6 +12,7 @@
 #define __LINUX_DEVFREQ_DEVFREQ_H__
 
 #include <linux/devfreq.h>
+struct module;
 
 #define DEVFREQ_NAME_LEN			16
 
@@ -50,6 +51,7 @@
 /**
  * struct devfreq_governor - Devfreq policy governor
  * @node:		list node - contains registered devfreq governors
+ * @owner:		Module that this governor belongs to
  * @name:		Governor's name
  * @attrs:		Governor's sysfs attribute flags
  * @flags:		Governor's feature flags
@@ -67,6 +69,7 @@
 struct devfreq_governor {
 	struct list_head node;
 
+	struct module *owner;
 	const char name[DEVFREQ_NAME_LEN];
 	const u64 attrs;
 	const u64 flags;
@@ -81,11 +84,28 @@ void devfreq_monitor_suspend(struct devfreq *devfreq);
 void devfreq_monitor_resume(struct devfreq *devfreq);
 void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay);
 
-int devfreq_add_governor(struct devfreq_governor *governor);
+/**
+ * devfreq_add_governor() - Add devfreq governor
+ * @governor:	The devfreq governor to be added
+ */
+#define devfreq_add_governor(governor) \
+	__devfreq_add_governor((governor), THIS_MODULE)
+int __devfreq_add_governor(struct devfreq_governor *governor,
+			   struct module *mod);
 int devfreq_remove_governor(struct devfreq_governor *governor);
 
-int devm_devfreq_add_governor(struct device *dev,
-			      struct devfreq_governor *governor);
+/**
+ * devm_devfreq_add_governor() - Add devfreq governor
+ * @dev:	device which adds devfreq governor
+ * @governor:	the devfreq governor to be added
+ *
+ * This is a resource-managed variant of devfreq_add_governor().
+ */
+#define devm_devfreq_add_governor(dev, governor) \
+	__devm_devfreq_add_governor((dev), (governor), THIS_MODULE)
+int __devm_devfreq_add_governor(struct device *dev,
+				struct devfreq_governor *governor,
+				struct module *mod);
 
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq);
 int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
-- 
2.43.0