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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>
This commit is contained in:
Rafael J. Wysocki 2013-02-09 15:29:11 +01:00
parent 87d4a4da73
commit f058cdf4cf
1 changed files with 17 additions and 14 deletions
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31
drivers/acpi/scan.c
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@ -95,6 +95,8 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
}
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 @@ void acpi_bus_hot_remove_device(void *context)
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 @@ void acpi_bus_hot_remove_device(void *context)
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 @@ static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used,
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 @@ 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);
}
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);