drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal

Fixes the deadlock when inserting and removing the ds2780.

Signed-off-by: Clifton Barnes <cabarnes@indesign-llc.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/power/ds2780_battery.c b/drivers/power/ds2780_battery.c
index 2571b4143784..91a783d72360 100644
--- 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_power_supply(struct device *dev)
 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_probe(struct platform_device *pdev)
         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_probe(struct platform_device *pdev)
                 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_remove(struct platform_device *pdev)
 {
         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);