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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 15/22] power_supply: Increment power supply use counter when obtaining references
Date: Tue, 10 Mar 2015 09:27:19 +0100	[thread overview]
Message-ID: <1425976046-20973-16-git-send-email-k.kozlowski@samsung.com> (raw)
In-Reply-To: <1425976046-20973-1-git-send-email-k.kozlowski@samsung.com>

Increment the power_supply.use_cnt usage counter on:
 - power_supply_get_by_phandle()
 - power_supply_get_by_name()
and decrement it on power_supply_put() call.

This helps tracking of valid usage of power supply instance by
consumers. The usage counter itself also allows safe calling of
power_supply_get_property-like functions even when driver unregisters
this power supply.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
---
 drivers/power/power_supply_core.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index b4ec14683b7f..2ed4a4a6b3c5 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -349,10 +349,16 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat
  */
 struct power_supply *power_supply_get_by_name(const char *name)
 {
+	struct power_supply *psy = NULL;
 	struct device *dev = class_find_device(power_supply_class, NULL, name,
 					power_supply_match_device_by_name);
 
-	return dev ? dev_get_drvdata(dev) : NULL;
+	if (dev) {
+		psy = dev_get_drvdata(dev);
+		atomic_inc(&psy->use_cnt);
+	}
+
+	return psy;
 }
 EXPORT_SYMBOL_GPL(power_supply_get_by_name);
 
@@ -367,6 +373,7 @@ void power_supply_put(struct power_supply *psy)
 {
 	might_sleep();
 
+	atomic_dec(&psy->use_cnt);
 	put_device(&psy->dev);
 }
 EXPORT_SYMBOL_GPL(power_supply_put);
@@ -393,6 +400,7 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
 							const char *property)
 {
 	struct device_node *power_supply_np;
+	struct power_supply *psy = NULL;
 	struct device *dev;
 
 	power_supply_np = of_parse_phandle(np, property, 0);
@@ -404,7 +412,12 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
 
 	of_node_put(power_supply_np);
 
-	return dev ? dev_get_drvdata(dev) : NULL;
+	if (dev) {
+		psy = dev_get_drvdata(dev);
+		atomic_inc(&psy->use_cnt);
+	}
+
+	return psy;
 }
 EXPORT_SYMBOL_GPL(power_supply_get_by_phandle);
 #endif /* CONFIG_OF */
-- 
1.9.1


  parent reply	other threads:[~2015-03-10  8:28 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 ` [PATCH v6 14/22] power_supply: Add power_supply_put for decrementing device reference counter Krzysztof Kozlowski
2015-03-10  8:27 ` Krzysztof Kozlowski [this message]
2015-03-10  8:27 ` [PATCH v6 16/22] power_supply: charger-manager: Decrement the power supply's " 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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