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authorLin Ming <ming.m.lin@intel.com>2012-09-14 00:26:33 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-09-14 00:26:33 +0200
commit40bf66ec9791f1452b90b82aadc3b6e6aee201f5 (patch)
tree677ca8a83277992ed9b8ad2ac75239fccc7f9e2d /drivers/acpi
parent8f7412a792bc989d1bddd3c802282eec09456d57 (diff)
downloadlinux-linaro-stable-40bf66ec9791f1452b90b82aadc3b6e6aee201f5.tar.gz
ACPI / PM: Fix resource_lock dead lock in acpi_power_on_device
Commit 0090def("ACPI: Add interface to register/unregister device to/from power resources") used resource_lock to protect the devices list that relies on power resource. It caused a mutex dead lock, as below acpi_power_on ---> lock resource_lock __acpi_power_on acpi_power_on_device acpi_power_get_inferred_state acpi_power_get_list_state ---> lock resource_lock This patch adds a new mutex "devices_lock" to protect the devices list and calls acpi_power_on_device in acpi_power_on, instead of __acpi_power_on, after the resource_lock is released. [rjw: Changed data type of a boolean variable to bool.] Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/power.c34
1 files changed, 23 insertions, 11 deletions
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index fc1803414629..cc2a2dcff336 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -107,6 +107,7 @@ struct acpi_power_resource {
/* List of devices relying on this power resource */
struct acpi_power_resource_device *devices;
+ struct mutex devices_lock;
};
static struct list_head acpi_power_resource_list;
@@ -225,7 +226,6 @@ static void acpi_power_on_device(struct acpi_power_managed_device *device)
static int __acpi_power_on(struct acpi_power_resource *resource)
{
- struct acpi_power_resource_device *device_list = resource->devices;
acpi_status status = AE_OK;
status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
@@ -238,19 +238,15 @@ static int __acpi_power_on(struct acpi_power_resource *resource)
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
resource->name));
- while (device_list) {
- acpi_power_on_device(device_list->device);
-
- device_list = device_list->next;
- }
-
return 0;
}
static int acpi_power_on(acpi_handle handle)
{
int result = 0;
+ bool resume_device = false;
struct acpi_power_resource *resource = NULL;
+ struct acpi_power_resource_device *device_list;
result = acpi_power_get_context(handle, &resource);
if (result)
@@ -266,10 +262,25 @@ static int acpi_power_on(acpi_handle handle)
result = __acpi_power_on(resource);
if (result)
resource->ref_count--;
+ else
+ resume_device = true;
}
mutex_unlock(&resource->resource_lock);
+ if (!resume_device)
+ return result;
+
+ mutex_lock(&resource->devices_lock);
+
+ device_list = resource->devices;
+ while (device_list) {
+ acpi_power_on_device(device_list->device);
+ device_list = device_list->next;
+ }
+
+ mutex_unlock(&resource->devices_lock);
+
return result;
}
@@ -355,7 +366,7 @@ static void __acpi_power_resource_unregister_device(struct device *dev,
if (acpi_power_get_context(res_handle, &resource))
return;
- mutex_lock(&resource->resource_lock);
+ mutex_lock(&resource->devices_lock);
prev = NULL;
curr = resource->devices;
while (curr) {
@@ -372,7 +383,7 @@ static void __acpi_power_resource_unregister_device(struct device *dev,
prev = curr;
curr = curr->next;
}
- mutex_unlock(&resource->resource_lock);
+ mutex_unlock(&resource->devices_lock);
}
/* Unlink dev from all power resources in _PR0 */
@@ -414,10 +425,10 @@ static int __acpi_power_resource_register_device(
power_resource_device->device = powered_device;
- mutex_lock(&resource->resource_lock);
+ mutex_lock(&resource->devices_lock);
power_resource_device->next = resource->devices;
resource->devices = power_resource_device;
- mutex_unlock(&resource->resource_lock);
+ mutex_unlock(&resource->devices_lock);
return 0;
}
@@ -721,6 +732,7 @@ static int acpi_power_add(struct acpi_device *device)
resource->device = device;
mutex_init(&resource->resource_lock);
+ mutex_init(&resource->devices_lock);
strcpy(resource->name, device->pnp.bus_id);
strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_POWER_CLASS);