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ACPI / scan: Make namespace scanning and trimming mutually exclusive

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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>
This commit is contained in:
Rafael J. Wysocki 2013-01-27 21:17:29 +01:00
parent bfee26dba0
commit c511cc1990
1 changed files with 12 additions and 4 deletions
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16
drivers/acpi/scan.c
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@ -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);