linux-kernel - [156/262] drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal

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Date:	Wed, 09 Nov 2011 13:27:58 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Clifton Barnes <cabarnes@...esign-llc.com>,
	Evgeniy Polyakov <zbr@...emap.net>
Subject: [156/262] drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Clifton Barnes <cabarnes@...esign-llc.com>

commit 0e053fcbbbc4d945247cb32cad2767b483cb65f8 upstream.

Fixes the deadlock when inserting and removing the ds2780.

Signed-off-by: Clifton Barnes <cabarnes@...esign-llc.com>
Cc: Evgeniy Polyakov <zbr@...emap.net>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/power/ds2780_battery.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/power/ds2780_battery.c
+++ b/drivers/power/ds2780_battery.c
@@ -39,6 +39,7 @@ struct ds2780_device_info {
 	struct device *dev;
 	struct power_supply bat;
 	struct device *w1_dev;
+	struct task_struct *mutex_holder;
 };
 
 enum current_types {
@@ -63,6 +64,9 @@ static inline struct power_supply *to_po
 static inline int ds2780_battery_io(struct ds2780_device_info *dev_info,
 	char *buf, int addr, size_t count, int io)
 {
+	if (dev_info->mutex_holder == current)
+		return w1_ds2780_io_nolock(dev_info->w1_dev, buf, addr, count, io);
+	else
 		return w1_ds2780_io(dev_info->w1_dev, buf, addr, count, io);
 }
 
@@ -775,6 +779,7 @@ static int __devinit ds2780_battery_prob
 	dev_info->bat.properties	= ds2780_battery_props;
 	dev_info->bat.num_properties	= ARRAY_SIZE(ds2780_battery_props);
 	dev_info->bat.get_property	= ds2780_battery_get_property;
+	dev_info->mutex_holder		= current;
 
 	ret = power_supply_register(&pdev->dev, &dev_info->bat);
 	if (ret) {
@@ -804,6 +809,8 @@ static int __devinit ds2780_battery_prob
 		goto fail_remove_bin_file;
 	}
 
+	dev_info->mutex_holder = NULL;
+
 	return 0;
 
 fail_remove_bin_file:
@@ -823,6 +830,8 @@ static int __devexit ds2780_battery_remo
 {
 	struct ds2780_device_info *dev_info = platform_get_drvdata(pdev);
 
+	dev_info->mutex_holder = current;
+
 	/* remove attributes */
 	sysfs_remove_group(&dev_info->bat.dev->kobj, &ds2780_attr_group);
 


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