3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lin Ming <ming.m....@intel.com>
commit 40bf66ec9791f1452b90b82aadc3b6e6aee201f5 upstream.
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....@intel.com>
Signed-off-by: Aaron Lu <aaron...@intel.com>
Signed-off-by: Rafael J. Wysocki <r...@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/acpi/power.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -103,6 +103,7 @@ 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;
@@ -221,7 +222,6 @@ static void acpi_power_on_device(struct
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);
@@ -234,19 +234,15 @@ static int __acpi_power_on(struct acpi_p
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)
@@ -262,10 +258,25 @@ static int acpi_power_on(acpi_handle han
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;
}
@@ -351,7 +362,7 @@ static void __acpi_power_resource_unregi
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) {
@@ -368,7 +379,7 @@ static void __acpi_power_resource_unregi
prev = curr;
curr = curr->next;
}
- mutex_unlock(&resource->resource_lock);
+ mutex_unlock(&resource->devices_lock);
}
/* Unlink dev from all power resources in _PR0 */
@@ -409,10 +420,10 @@ static int __acpi_power_resource_registe
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;
}
@@ -715,6 +726,7 @@ static int acpi_power_add(struct acpi_de
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);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
