Commit e0ae8fee authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
parent f943db40

drivers/acpi/scan.c

+6 −9
Original line number Diff line number Diff line
@@ -207,8 +207,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 
		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 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 
					    ACPI_UINT32_MAX,

					    acpi_bus_online_companions, NULL,

					    NULL, NULL);



			unlock_device_hotplug();



			put_device(&device->dev);

			return -EBUSY;

		}
@@ -252,8 +247,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 


	acpi_bus_trim(device);



	unlock_device_hotplug();



	/* Device node has been unregistered. */

	put_device(&device->dev);

	device = NULL;
@@ -309,6 +302,7 @@ static void acpi_bus_device_eject(void *context) 
	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 @@ static void acpi_bus_device_eject(void *context) 


 out:

	mutex_unlock(&acpi_scan_lock);

	unlock_device_hotplug();

	return;



 err_out:
@@ -346,8 +341,8 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source) 
	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 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source) 
		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 @@ void acpi_bus_hot_remove_device(void *context) 
	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 @@ void acpi_bus_hot_remove_device(void *context) 
					  NULL);



	mutex_unlock(&acpi_scan_lock);

	unlock_device_hotplug();

	kfree(context);

}

EXPORT_SYMBOL(acpi_bus_hot_remove_device);

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