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

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 <>
Acked-by: default avatarYinghai Lu <>
parent bfee26db
......@@ -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);
......@@ -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;
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;
return error;
......@@ -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)
* 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);
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