From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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@xxxxxxxxx>
---
drivers/acpi/scan.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_
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);
@@ -1612,19 +1613,22 @@ static acpi_status acpi_bus_device_attac
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);
@@ -1653,6 +1657,8 @@ static acpi_status acpi_bus_remove(acpi_
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.
@@ -1667,6 +1673,8 @@ void acpi_bus_trim(struct acpi_device *s
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);
--
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