ACPI / scan: Make acpi_bus_hot_remove_device() acquire the scan lock
The ACPI scan lock has been introduced to prevent acpi_bus_scan()
and acpi_bus_trim() from running in parallel with each other for
overlapping ACPI namespace scopes. However, it is not sufficient
to do that, because if acpi_bus_scan() is run (for an overlapping
namespace scope) right after the acpi_bus_trim() in
acpi_bus_hot_remove_device(), the subsequent eject will remove
devices without removing the corresponding struct acpi_device
objects (and possibly companion "physical" device objects).
Therefore acpi_bus_hot_remove_device() has to acquire the scan
lock before carrying out the bus trimming and hold it through
the evaluation of _EJ0, so make that happen.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index a48b6e9..75fb14f 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -95,6 +95,8 @@
}
static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
+static void __acpi_bus_trim(struct acpi_device *start);
+
/**
* acpi_bus_hot_remove_device: hot-remove a device and its children
* @context: struct acpi_eject_event pointer (freed in this func)
@@ -114,10 +116,12 @@
acpi_status status = AE_OK;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
+ mutex_lock(&acpi_scan_lock);
+
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Hot-removing device %s...\n", dev_name(&device->dev)));
- acpi_bus_trim(device);
+ __acpi_bus_trim(device);
/* Device node has been released. */
device = NULL;
@@ -146,18 +150,14 @@
status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND)
- printk(KERN_WARNING PREFIX
- "Eject device failed\n");
- goto err_out;
+ acpi_handle_warn(handle, "Eject failed\n");
+
+ /* Tell the firmware the hot-remove operation has failed. */
+ acpi_evaluate_hotplug_ost(handle, ej_event->event,
+ ost_code, NULL);
}
- kfree(context);
- return;
-
-err_out:
- /* Inform firmware the hot-remove operation has completed w/ error */
- (void) acpi_evaluate_hotplug_ost(handle,
- ej_event->event, ost_code, NULL);
+ mutex_unlock(&acpi_scan_lock);
kfree(context);
return;
}
@@ -1683,10 +1683,8 @@
return AE_OK;
}
-void acpi_bus_trim(struct acpi_device *start)
+static 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.
@@ -1701,7 +1699,12 @@
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);
+}
+void acpi_bus_trim(struct acpi_device *start)
+{
+ mutex_lock(&acpi_scan_lock);
+ __acpi_bus_trim(start);
mutex_unlock(&acpi_scan_lock);
}
EXPORT_SYMBOL_GPL(acpi_bus_trim);