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Subject[PATCH 06/12] PM / OPP: Add 'struct kref' to struct dev_pm_opp
Date
Add kref to struct dev_pm_opp for easier accounting of the OPPs.

Note that the OPPs are freed under the opp_table->lock mutex only.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp/core.c | 27 ++++++++++++---------------
drivers/base/power/opp/opp.h | 3 +++
include/linux/pm_opp.h | 3 +++
3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index ec833a8f7aa5..12be0f29f2ad 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -949,20 +949,10 @@ static void _kfree_opp_rcu(struct rcu_head *head)
kfree_rcu(opp, rcu_head);
}

-/**
- * _opp_remove() - Remove an OPP from a table definition
- * @opp_table: points back to the opp_table struct this opp belongs to
- * @opp: pointer to the OPP to remove
- *
- * This function removes an opp definition from the opp table.
- *
- * Locking: The internal opp_table and opp structures are RCU protected.
- * It is assumed that the caller holds required mutex for an RCU updater
- * strategy.
- */
-static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp)
+static void _opp_kref_release(struct kref *kref)
{
- mutex_lock(&opp_table->lock);
+ struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
+ struct opp_table *opp_table = opp->opp_table;

/*
* Notify the changes in the availability of the operable
@@ -977,6 +967,12 @@ static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp)
dev_pm_opp_put_opp_table(opp_table);
}

+void dev_pm_opp_put(struct dev_pm_opp *opp)
+{
+ kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put);
+
/**
* dev_pm_opp_remove() - Remove an OPP from OPP table
* @dev: device for which we do this operation
@@ -1020,7 +1016,7 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
goto unlock;
}

- _opp_remove(opp_table, opp);
+ dev_pm_opp_put(opp);
unlock:
mutex_unlock(&opp_table_lock);
}
@@ -1125,6 +1121,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
mutex_unlock(&opp_table->lock);

new_opp->opp_table = opp_table;
+ kref_init(&new_opp->kref);

/* Get a reference to the OPP table */
_get_opp_table_kref(opp_table);
@@ -1820,7 +1817,7 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev,
/* Free static OPPs */
list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) {
if (remove_all || !opp->dynamic)
- _opp_remove(opp_table, opp);
+ dev_pm_opp_put(opp);
}
} else {
_remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table);
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 8435a0eb27be..bd929ba6efaf 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -16,6 +16,7 @@

#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/limits.h>
#include <linux/pm_opp.h>
@@ -56,6 +57,7 @@ extern struct list_head opp_tables;
* are protected by the opp_table_lock for integrity.
* IMPORTANT: the opp nodes should be maintained in increasing
* order.
+ * @kref: for reference count of the OPP.
* @available: true/false - marks if this OPP as available or not
* @dynamic: not-created from static DT entries.
* @turbo: true if turbo (boost) OPP
@@ -73,6 +75,7 @@ extern struct list_head opp_tables;
*/
struct dev_pm_opp {
struct list_head node;
+ struct kref kref;

bool available;
bool dynamic;
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 99787cbcaab2..731d548657aa 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -102,6 +102,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,

struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
unsigned long *freq);
+void dev_pm_opp_put(struct dev_pm_opp *opp);

int dev_pm_opp_add(struct device *dev, unsigned long freq,
unsigned long u_volt);
@@ -193,6 +194,8 @@ static inline struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
return ERR_PTR(-ENOTSUPP);
}

+static inline void dev_pm_opp_put(struct dev_pm_opp *opp) {}
+
static inline int dev_pm_opp_add(struct device *dev, unsigned long freq,
unsigned long u_volt)
{
--
2.7.1.410.g6faf27b
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