[PATCH RESEND v2 0/7] power_supply: Decrement the device reference counter

[PATCH RESEND v2 0/7] power_supply: Decrement the device reference counter

[Krzysztof Kozlowski]

Hi,


Resending with some new acks.
Whole patchset should be taken at once (everything depends on patch 1).
Depends on [1].


Changes since v1:
=================
1. Remove check for non-NULL in power_supply_put (suggested by
   Pavel Machek).
2. Add Pavel Machek's ack.


Description:
============
The reference counter of device allocated for power supply was
incremented with each call to power_supply_get_by_name() and
power_supply_get_by_phandle().

Add a symmetric 'put' operation so the device could be released after
final put_device() call during supply unregistering.


Rebased on next-20141104 + mine [1] patchset.
Tested on Trats2 board (max77693 + charger manager).

Kindly asking for reviewing and testing other drivers.

Best regards,
Krzysztof


[1] power_supply: Add API for safe access of get_property-like function attrs
https://lkml.org/lkml/2014/11/4/527


Krzysztof Kozlowski (7):
  power_supply: Add power_supply_put for decrementing device reference
    counter
  power: charger-manager: Decrement the power supply's device reference
    counter
  x86/olpc/xo1/sci: Use newly added power_supply_put API
  x86/olpc/xo15/sci: Use newly added power_supply_put API
  power: 88pm860x_charger: Decrement the power supply's device reference
    counter
  power: bq2415x_charger: Decrement the power supply's device reference
    counter
  mfd: ab8500: Decrement the power supply's device reference counter

 arch/x86/platform/olpc/olpc-xo1-sci.c  |  4 +-
 arch/x86/platform/olpc/olpc-xo15-sci.c |  4 +-
 drivers/mfd/ab8500-sysctrl.c           |  2 +
 drivers/power/88pm860x_charger.c       | 11 +++++-
 drivers/power/bq2415x_charger.c        |  6 ++-
 drivers/power/charger-manager.c        | 70 +++++++++++++++++++++++-----------
 drivers/power/power_supply_core.c      | 38 ++++++++++++++++++
 include/linux/power_supply.h           |  1 +
 8 files changed, 106 insertions(+), 30 deletions(-)

-- 
1.9.1

[PATCH RESEND v2 1/7] power_supply: Add power_supply_put for decrementing device reference counter

[Krzysztof Kozlowski]

The power_supply_get_by_phandle() and power_supply_get_by_name() use
function class_find_device() for obtaining the reference to power
supply. Each use of class_find_device() increases the power supply's
device reference counter.

However the reference counter was not decreased by users of this API.
Thus final device_unregister() call from power_supply_unregister() could
not release the device and clean up its resources. This lead to memory
leak if at least once power_supply_get_by_*() was called between
registering and unregistering the power supply.

Add and document new API power_supply_put() for decrementing the
reference counter.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 drivers/power/power_supply_core.c | 38 ++++++++++++++++++++++++++++++++++++++
 include/linux/power_supply.h      |  1 +
 2 files changed, 39 insertions(+)

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index bd8f5be0d976..cf860d2fd8c9 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -331,6 +331,17 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat
 	return strcmp(psy->name, name) == 0;
 }
 
+/**
+ * power_supply_get_by_name() - Search for a power supply and returns its ref
+ * @name: Power supply name to fetch
+ *
+ * If power supply was found, it increases reference count for the
+ * internal power supply's device. The user should power_supply_put()
+ * after usage.
+ *
+ * Return: On success returns a reference to a power supply with
+ * matching name equals to @name, a NULL otherwise.
+ */
 struct power_supply *power_supply_get_by_name(const char *name)
 {
 	struct device *dev = class_find_device(power_supply_class, NULL, name,
@@ -340,12 +351,39 @@ struct power_supply *power_supply_get_by_name(const char *name)
 }
 EXPORT_SYMBOL_GPL(power_supply_get_by_name);
 
+/**
+ * power_supply_put() - Drop reference obtained with power_supply_get_by_name
+ * @psy: Reference to put
+ *
+ * The reference to power supply should be put before unregistering
+ * the power supply.
+ */
+void power_supply_put(struct power_supply *psy)
+{
+	might_sleep();
+
+	put_device(psy->dev);
+}
+EXPORT_SYMBOL_GPL(power_supply_put);
+
 #ifdef CONFIG_OF
 static int power_supply_match_device_node(struct device *dev, const void *data)
 {
 	return dev->parent && dev->parent->of_node == data;
 }
 
+/**
+ * power_supply_get_by_phandle() - Search for a power supply and returns its ref
+ * @np: Pointer to device node holding phandle property
+ * @phandle_name: Name of property holding a power supply name
+ *
+ * If power supply was found, it increases reference count for the
+ * internal power supply's device. The user should power_supply_put()
+ * after usage.
+ *
+ * Return: On success returns a reference to a power supply with
+ * matching name equals to value under @property, NULL or ERR_PTR otherwise.
+ */
 struct power_supply *power_supply_get_by_phandle(struct device_node *np,
 							const char *property)
 {
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 0ef515301aaf..9abb2aef55eb 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -262,6 +262,7 @@ extern struct atomic_notifier_head power_supply_notifier;
 extern int power_supply_reg_notifier(struct notifier_block *nb);
 extern void power_supply_unreg_notifier(struct notifier_block *nb);
 extern struct power_supply *power_supply_get_by_name(const char *name);
+extern void power_supply_put(struct power_supply *psy);
 #ifdef CONFIG_OF
 extern struct power_supply *power_supply_get_by_phandle(struct device_node *np,
 							const char *property);
-- 
1.9.1

[PATCH RESEND v2 2/7] power: charger-manager: Decrement the power supply's device reference counter

[Krzysztof Kozlowski]

Use power_supply_put() to decrement the power supply's device reference
counter.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 drivers/power/charger-manager.c | 70 +++++++++++++++++++++++++++--------------
 1 file changed, 47 insertions(+), 23 deletions(-)

diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
index c4ca346dcd50..7455ac95ecbc 100644
--- a/drivers/power/charger-manager.c
+++ b/drivers/power/charger-manager.c
@@ -116,6 +116,7 @@ static bool is_batt_present(struct charger_manager *cm)
 				&val);
 		if (ret == 0 && val.intval)
 			present = true;
+		power_supply_put(psy);
 		break;
 	case CM_CHARGER_STAT:
 		for (i = 0; cm->desc->psy_charger_stat[i]; i++) {
@@ -129,6 +130,7 @@ static bool is_batt_present(struct charger_manager *cm)
 
 			ret = power_supply_get_property(psy,
 				POWER_SUPPLY_PROP_PRESENT, &val);
+			power_supply_put(psy);
 			if (ret == 0 && val.intval) {
 				present = true;
 				break;
@@ -166,6 +168,7 @@ static bool is_ext_pwr_online(struct charger_manager *cm)
 
 		ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE,
 				&val);
+		power_supply_put(psy);
 		if (ret == 0 && val.intval) {
 			online = true;
 			break;
@@ -195,6 +198,7 @@ static int get_batt_uV(struct charger_manager *cm, int *uV)
 
 	ret = power_supply_get_property(fuel_gauge,
 				POWER_SUPPLY_PROP_VOLTAGE_NOW, &val);
+	power_supply_put(fuel_gauge);
 	if (ret)
 		return ret;
 
@@ -238,10 +242,13 @@ static bool is_charging(struct charger_manager *cm)
 		if (ret) {
 			dev_warn(cm->dev, "Cannot read ONLINE value from %s\n",
 				 cm->desc->psy_charger_stat[i]);
+			power_supply_put(psy);
 			continue;
 		}
-		if (val.intval == 0)
+		if (val.intval == 0) {
+			power_supply_put(psy);
 			continue;
+		}
 
 		/*
 		 * 3. The charger should not be FULL, DISCHARGING,
@@ -249,6 +256,7 @@ static bool is_charging(struct charger_manager *cm)
 		 */
 		ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS,
 				&val);
+		power_supply_put(psy);
 		if (ret) {
 			dev_warn(cm->dev, "Cannot read STATUS value from %s\n",
 				 cm->desc->psy_charger_stat[i]);
@@ -276,6 +284,7 @@ static bool is_full_charged(struct charger_manager *cm)
 	struct charger_desc *desc = cm->desc;
 	union power_supply_propval val;
 	struct power_supply *fuel_gauge;
+	bool is_full = false;
 	int ret = 0;
 	int uV;
 
@@ -293,15 +302,19 @@ static bool is_full_charged(struct charger_manager *cm)
 		/* Not full if capacity of fuel gauge isn't full */
 		ret = power_supply_get_property(fuel_gauge,
 				POWER_SUPPLY_PROP_CHARGE_FULL, &val);
-		if (!ret && val.intval > desc->fullbatt_full_capacity)
-			return true;
+		if (!ret && val.intval > desc->fullbatt_full_capacity) {
+			is_full = true;
+			goto out;
+		}
 	}
 
 	/* Full, if it's over the fullbatt voltage */
 	if (desc->fullbatt_uV > 0) {
 		ret = get_batt_uV(cm, &uV);
-		if (!ret && uV >= desc->fullbatt_uV)
-			return true;
+		if (!ret && uV >= desc->fullbatt_uV) {
+			is_full = true;
+			goto out;
+		}
 	}
 
 	/* Full, if the capacity is more than fullbatt_soc */
@@ -310,11 +323,15 @@ static bool is_full_charged(struct charger_manager *cm)
 
 		ret = power_supply_get_property(fuel_gauge,
 				POWER_SUPPLY_PROP_CAPACITY, &val);
-		if (!ret && val.intval >= desc->fullbatt_soc)
-			return true;
+		if (!ret && val.intval >= desc->fullbatt_soc) {
+			is_full = true;
+			goto out;
+		}
 	}
 
-	return false;
+out:
+	power_supply_put(fuel_gauge);
+	return is_full;
 }
 
 /**
@@ -587,14 +604,18 @@ static int cm_get_battery_temperature_by_psy(struct charger_manager *cm,
 					int *temp)
 {
 	struct power_supply *fuel_gauge;
+	int ret;
 
 	fuel_gauge = power_supply_get_by_name(cm->desc->psy_fuel_gauge);
 	if (!fuel_gauge)
 		return -ENODEV;
 
-	return power_supply_get_property(fuel_gauge,
+	ret = power_supply_get_property(fuel_gauge,
 				POWER_SUPPLY_PROP_TEMP,
 				(union power_supply_propval *)temp);
+	power_supply_put(fuel_gauge);
+
+	return ret;
 }
 
 static int cm_get_battery_temperature(struct charger_manager *cm,
@@ -876,7 +897,7 @@ static int charger_get_property(struct power_supply *psy,
 	struct charger_manager *cm = container_of(psy,
 			struct charger_manager, charger_psy);
 	struct charger_desc *desc = cm->desc;
-	struct power_supply *fuel_gauge;
+	struct power_supply *fuel_gauge = NULL;
 	int ret = 0;
 	int uV;
 
@@ -919,18 +940,18 @@ static int charger_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
 		return cm_get_battery_temperature(cm, &val->intval);
 	case POWER_SUPPLY_PROP_CAPACITY:
-		fuel_gauge = power_supply_get_by_name(cm->desc->psy_fuel_gauge);
-		if (!fuel_gauge) {
-			ret = -ENODEV;
-			break;
-		}
-
 		if (!is_batt_present(cm)) {
 			/* There is no battery. Assume 100% */
 			val->intval = 100;
 			break;
 		}
 
+		fuel_gauge = power_supply_get_by_name(cm->desc->psy_fuel_gauge);
+		if (!fuel_gauge) {
+			ret = -ENODEV;
+			break;
+		}
+
 		ret = power_supply_get_property(fuel_gauge,
 					POWER_SUPPLY_PROP_CAPACITY, val);
 		if (ret)
@@ -1005,6 +1026,8 @@ static int charger_get_property(struct power_supply *psy,
 	default:
 		return -EINVAL;
 	}
+	if (fuel_gauge)
+		power_supply_put(fuel_gauge);
 	return ret;
 }
 
@@ -1803,13 +1826,7 @@ static int charger_manager_probe(struct platform_device *pdev)
 				desc->psy_charger_stat[i]);
 			return -ENODEV;
 		}
-	}
-
-	fuel_gauge = power_supply_get_by_name(desc->psy_fuel_gauge);
-	if (!fuel_gauge) {
-		dev_err(&pdev->dev, "Cannot find power supply \"%s\"\n",
-			desc->psy_fuel_gauge);
-		return -ENODEV;
+		power_supply_put(psy);
 	}
 
 	if (desc->polling_interval_ms == 0 ||
@@ -1849,6 +1866,12 @@ static int charger_manager_probe(struct platform_device *pdev)
 	cm->charger_psy.num_properties = psy_default.num_properties;
 
 	/* Find which optional psy-properties are available */
+	fuel_gauge = power_supply_get_by_name(desc->psy_fuel_gauge);
+	if (!fuel_gauge) {
+		dev_err(&pdev->dev, "Cannot find power supply \"%s\"\n",
+			desc->psy_fuel_gauge);
+		return -ENODEV;
+	}
 	if (!power_supply_get_property(fuel_gauge,
 					  POWER_SUPPLY_PROP_CHARGE_NOW, &val)) {
 		cm->charger_psy.properties[cm->charger_psy.num_properties] =
@@ -1868,6 +1891,7 @@ static int charger_manager_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Failed to initialize thermal data\n");
 		cm->desc->measure_battery_temp = false;
 	}
+	power_supply_put(fuel_gauge);
 
 	INIT_DELAYED_WORK(&cm->fullbatt_vchk_work, fullbatt_vchk);
 
-- 
1.9.1

[PATCH RESEND v2 3/7] x86/olpc/xo1/sci: Use newly added power_supply_put API

[Krzysztof Kozlowski]

Replace direct usage of put_device() with new API: power_supply_put().

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 arch/x86/platform/olpc/olpc-xo1-sci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/olpc/olpc-xo1-sci.c b/arch/x86/platform/olpc/olpc-xo1-sci.c
index 9a2e590dd202..7fa8b3b53bc0 100644
--- a/arch/x86/platform/olpc/olpc-xo1-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo1-sci.c
@@ -61,7 +61,7 @@ static void battery_status_changed(void)
 
 	if (psy) {
 		power_supply_changed(psy);
-		put_device(psy->dev);
+		power_supply_put(psy);
 	}
 }
 
@@ -71,7 +71,7 @@ static void ac_status_changed(void)
 
 	if (psy) {
 		power_supply_changed(psy);
-		put_device(psy->dev);
+		power_supply_put(psy);
 	}
 }
 
-- 
1.9.1

[PATCH RESEND v2 4/7] x86/olpc/xo15/sci: Use newly added power_supply_put API

[Krzysztof Kozlowski]

Replace direct usage of put_device() with new API: power_supply_put().

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 arch/x86/platform/olpc/olpc-xo15-sci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/olpc/olpc-xo15-sci.c b/arch/x86/platform/olpc/olpc-xo15-sci.c
index 08e350e757dc..55130846ac87 100644
--- a/arch/x86/platform/olpc/olpc-xo15-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo15-sci.c
@@ -83,7 +83,7 @@ static void battery_status_changed(void)
 
 	if (psy) {
 		power_supply_changed(psy);
-		put_device(psy->dev);
+		power_supply_put(psy);
 	}
 }
 
@@ -93,7 +93,7 @@ static void ac_status_changed(void)
 
 	if (psy) {
 		power_supply_changed(psy);
-		put_device(psy->dev);
+		power_supply_put(psy);
 	}
 }
 
-- 
1.9.1

[PATCH RESEND v2 5/7] power: 88pm860x_charger: Decrement the power supply's device reference counter

[Krzysztof Kozlowski]

Use power_supply_put() to decrement the power supply's device reference
counter.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 drivers/power/88pm860x_charger.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/power/88pm860x_charger.c b/drivers/power/88pm860x_charger.c
index 534b3e2e3487..48aa0d829cb0 100644
--- a/drivers/power/88pm860x_charger.c
+++ b/drivers/power/88pm860x_charger.c
@@ -298,13 +298,18 @@ static int set_charging_fsm(struct pm860x_charger_info *info)
 		return -EINVAL;
 	ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_VOLTAGE_NOW,
 			&data);
-	if (ret)
+	if (ret) {
+		power_supply_put(psy);
 		return ret;
+	}
 	vbatt = data.intval / 1000;
 
 	ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_PRESENT, &data);
-	if (ret)
+	if (ret) {
+		power_supply_put(psy);
 		return ret;
+	}
+	power_supply_put(psy);
 
 	mutex_lock(&info->lock);
 	info->present = data.intval;
@@ -447,6 +452,7 @@ static irqreturn_t pm860x_temp_handler(int irq, void *data)
 
 	set_charging_fsm(info);
 out:
+	power_supply_put(psy);
 	return IRQ_HANDLED;
 }
 
@@ -507,6 +513,7 @@ static irqreturn_t pm860x_done_handler(int irq, void *data)
 
 out:
 	mutex_unlock(&info->lock);
+	power_supply_put(psy);
 	dev_dbg(info->dev, "%s, Allowed: %d\n", __func__, info->allowed);
 	set_charging_fsm(info);
 
-- 
1.9.1

[PATCH RESEND v2 6/7] power: bq2415x_charger: Decrement the power supply's device reference counter

[Krzysztof Kozlowski]

Use power_supply_put() to decrement the power supply's device reference
counter (increased by power_supply_get_by_name() or
power_supply_get_by_phandle()).

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 drivers/power/bq2415x_charger.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c
index 2f80de0410d9..00809dcdd34e 100644
--- a/drivers/power/bq2415x_charger.c
+++ b/drivers/power/bq2415x_charger.c
@@ -1686,6 +1686,8 @@ error_4:
 error_3:
 	bq2415x_power_supply_exit(bq);
 error_2:
+	if (!IS_ERR(bq->notify_psy))
+		power_supply_put(bq->notify_psy);
 	kfree(name);
 error_1:
 	mutex_lock(&bq2415x_id_mutex);
@@ -1701,8 +1703,10 @@ static int bq2415x_remove(struct i2c_client *client)
 {
 	struct bq2415x_device *bq = i2c_get_clientdata(client);
 
-	if (bq->notify_psy)
+	if (bq->notify_psy) {
 		power_supply_unreg_notifier(&bq->nb);
+		power_supply_put(bq->notify_psy);
+	}
 
 	bq2415x_sysfs_exit(bq);
 	bq2415x_power_supply_exit(bq);
-- 
1.9.1

[PATCH RESEND v2 7/7] mfd: ab8500: Decrement the power supply's device reference counter

[Krzysztof Kozlowski]

Use power_supply_put() to decrement the power supply's device reference
counter.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/mfd/ab8500-sysctrl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mfd/ab8500-sysctrl.c b/drivers/mfd/ab8500-sysctrl.c
index f7f44b34896a..962f32492647 100644
--- a/drivers/mfd/ab8500-sysctrl.c
+++ b/drivers/mfd/ab8500-sysctrl.c
@@ -51,6 +51,7 @@ static void ab8500_power_off(void)
 
 		ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE,
 				&val);
+		power_supply_put(psy);
 
 		if (!ret && val.intval) {
 			charger_present = true;
@@ -73,6 +74,7 @@ static void ab8500_power_off(void)
 			       pss[i]);
 			machine_restart("charging");
 		}
+		power_supply_put(psy);
 	}
 
 shutdown:
-- 
1.9.1