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Commit c511cc19 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / scan: Make namespace scanning and trimming mutually exclusive 



There is no guarantee that acpi_bus_scan() and acpi_bus_trim() will
not be run in parallel for the same scope of the ACPI namespace,
which may lead to a great deal of confusion, so introduce a new mutex
to prevent that from happening.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarYinghai Lu <yinghai@kernel.org>
parent bfee26db

drivers/acpi/scan.c

+12 −4
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_platform_device_ids[] = { 


static LIST_HEAD(acpi_device_list);

static LIST_HEAD(acpi_bus_id_list);

static DEFINE_MUTEX(acpi_scan_lock);

DEFINE_MUTEX(acpi_device_lock);

LIST_HEAD(acpi_wakeup_device_list);
@@ -1587,19 +1588,22 @@ static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used, 
int acpi_bus_scan(acpi_handle handle)

{

	void *device = NULL;

	int error = 0;



	mutex_lock(&acpi_scan_lock);



	if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device)))

		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,

				    acpi_bus_check_add, NULL, NULL, &device);



	if (!device)

		return -ENODEV;



	if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))

		error = -ENODEV;

	else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))

		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,

				    acpi_bus_device_attach, NULL, NULL, NULL);



	return 0;

	mutex_unlock(&acpi_scan_lock);

	return error;

}

EXPORT_SYMBOL(acpi_bus_scan);
@@ -1628,6 +1632,8 @@ static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used, 


void acpi_bus_trim(struct acpi_device *start)

{

	mutex_lock(&acpi_scan_lock);



	/*

	 * Execute acpi_bus_device_detach() as a post-order callback to detach

	 * all ACPI drivers from the device nodes being removed.
@@ -1642,6 +1648,8 @@ void acpi_bus_trim(struct acpi_device *start) 
	acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL,

			    acpi_bus_remove, NULL, NULL);

	acpi_bus_remove(start->handle, 0, NULL, NULL);



	mutex_unlock(&acpi_scan_lock);

}

EXPORT_SYMBOL_GPL(acpi_bus_trim);