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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d37f290..4375465 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -52,6 +52,7 @@
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 @@
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 @@
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 @@
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);