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From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
To: Sebastian Reichel <sre@kernel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Jiri Kosina <jkosina@suse.cz>,
	David Herrmann <dh.herrmann@googlemail.com>,
	Cezary Jackiewicz <cezary.jackiewicz@gmail.com>,
	Darren Hart <dvhart@infradead.org>,
	Support Opensource <support.opensource@diasemi.com>,
	Milo Kim <milo.kim@ti.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Samuel Ortiz <sameo@linux.intel.com>,
	Lee Jones <lee.jones@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org, linux-input@vger.kernel.org,
	platform-driver-x86@vger.kernel.org,
	patches@opensource.wolfsonmicro.com, ac100@lists.launchpad.net,
	linux-tegra@vger.kernel.org, devel@driverdev.osuosl.org
Cc: Thomas Gleixner <tglx@linutronix.de>, Pavel Machek <pavel@ucw.cz>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>
Subject: [PATCH v6 14/22] power_supply: Add power_supply_put for decrementing device reference counter
Date: Tue, 10 Mar 2015 09:27:18 +0100	[thread overview]
Message-ID: <1425976046-20973-15-git-send-email-k.kozlowski@samsung.com> (raw)
In-Reply-To: <1425976046-20973-1-git-send-email-k.kozlowski@samsung.com>

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>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
---
 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 e51405b176c8..b4ec14683b7f 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -336,6 +336,17 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat
 	return strcmp(psy->desc->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,
@@ -345,12 +356,39 @@ 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 ea15eb68f609..75a1dd8dc56e 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -282,6 +282,7 @@ 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


  parent reply	other threads:[~2015-03-10  8:34 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-10  8:27 [PATCH v6 00/22] power_supply: Allow safe usage of power supply Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 01/22] compal-laptop: Fix leaking hwmon device Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 02/22] compal-laptop: Check return value of power_supply_register Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 03/22] power_supply: Add driver private data Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 04/22] power_supply: Move run-time configuration to separate structure Krzysztof Kozlowski
2015-03-11 16:06   ` Jiri Kosina
2015-03-10  8:27 ` [PATCH v6 05/22] power_supply: Add API for safe access of power supply function attrs Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 06/22] power_supply: sysfs: Use power_supply_*() API for accessing " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 07/22] power_supply: 88pm860x_charger: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 08/22] power_supply: ab8500: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 09/22] mfd: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 10/22] power_supply: apm_power: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 11/22] power_supply: bq2415x_charger: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 12/22] power_supply: charger-manager: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 13/22] power_supply: Change ownership from driver to core Krzysztof Kozlowski
2015-03-12 23:11   ` Rafael J. Wysocki
2015-03-10  8:27 ` Krzysztof Kozlowski [this message]
2015-03-10  8:27 ` [PATCH v6 15/22] power_supply: Increment power supply use counter when obtaining references Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 16/22] power_supply: charger-manager: Decrement the power supply's device reference counter Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 17/22] x86/olpc/xo1/sci: Use newly added power_supply_put API Krzysztof Kozlowski
2015-03-12 11:20   ` Ingo Molnar
2015-03-10  8:27 ` [PATCH v6 18/22] x86/olpc/xo15/sci: " Krzysztof Kozlowski
2015-03-12 11:21   ` Ingo Molnar
2015-03-10  8:27 ` [PATCH v6 19/22] power_supply: 88pm860x_charger: Decrement the power supply's device reference counter Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 20/22] power_supply: bq2415x_charger: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 21/22] mfd: ab8500: " Krzysztof Kozlowski
2015-03-10  8:27 ` [PATCH v6 22/22] arm: mach-pxa: " Krzysztof Kozlowski
2015-03-11  7:51 ` [PATCH v6 00/22] power_supply: Allow safe usage of power supply Krzysztof Kozlowski
2015-03-11  7:52 ` Krzysztof Kozlowski

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