ACPI / scan: Change ordering of locks for device hotplug
Change the ordering of device hotplug locks in scan.c so that
acpi_scan_lock is always acquired after device_hotplug_lock.
This will make it possible to use device_hotplug_lock around some
code paths that acquire acpi_scan_lock safely (most importantly
system suspend and hibernation). Apart from that, acpi_scan_lock
is platform-specific and device_hotplug_lock is general, so the
new ordering appears to be more appropriate from the overall
design viewpoint.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e2f6d9d..42982b5 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -207,8 +207,6 @@
return -EINVAL;
}
- lock_device_hotplug();
-
/*
* Carry out two passes here and ignore errors in the first pass,
* because if the devices in question are memory blocks and
@@ -239,9 +237,6 @@
ACPI_UINT32_MAX,
acpi_bus_online_companions, NULL,
NULL, NULL);
-
- unlock_device_hotplug();
-
put_device(&device->dev);
return -EBUSY;
}
@@ -252,8 +247,6 @@
acpi_bus_trim(device);
- unlock_device_hotplug();
-
/* Device node has been unregistered. */
put_device(&device->dev);
device = NULL;
@@ -309,6 +302,7 @@
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
int error;
+ lock_device_hotplug();
mutex_lock(&acpi_scan_lock);
acpi_bus_get_device(handle, &device);
@@ -332,6 +326,7 @@
out:
mutex_unlock(&acpi_scan_lock);
+ unlock_device_hotplug();
return;
err_out:
@@ -346,8 +341,8 @@
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
int error;
- mutex_lock(&acpi_scan_lock);
lock_device_hotplug();
+ mutex_lock(&acpi_scan_lock);
if (ost_source != ACPI_NOTIFY_BUS_CHECK) {
acpi_bus_get_device(handle, &device);
@@ -373,9 +368,9 @@
kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
out:
- unlock_device_hotplug();
acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
mutex_unlock(&acpi_scan_lock);
+ unlock_device_hotplug();
}
static void acpi_scan_bus_check(void *context)
@@ -466,6 +461,7 @@
acpi_handle handle = device->handle;
int error;
+ lock_device_hotplug();
mutex_lock(&acpi_scan_lock);
error = acpi_scan_hot_remove(device);
@@ -475,6 +471,7 @@
NULL);
mutex_unlock(&acpi_scan_lock);
+ unlock_device_hotplug();
kfree(context);
}
EXPORT_SYMBOL(acpi_bus_hot_remove_device);
