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ACPI / hotplug: Add demand_offline hotplug profile flag 

Add a new ACPI hotplug profile flag, demand_offline, such that if
set for the given ACPI device object's scan handler, it will cause
acpi_scan_hot_remove() to check if that device object's physical
companions are offline upfront and fail the hot removal if that
is not the case.

That flag will be useful to overcome a problem with containers on
some system where they can only be hot-removed after some cleanup
operations carried out by user space, which needs to be notified
of the container hot-removal before the kernel attempts to offline
devices in the container.  In those cases the current implementation
of acpi_scan_hot_remove() is not sufficient, because it first tries
to offline the devices in the container and only if that is
suffcessful it tries to offline the container itself.  As a result,
the container hot-removal notification is not delivered to user space
at the right time.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2013-12-29 15:25:35 +01:00
parent bfecc2b3e3
commit d22ddcbc4f
2 changed files with 39 additions and 5 deletions
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41
drivers/acpi/scan.c
View File

@ -126,6 +126,24 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
}
static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
static bool acpi_scan_is_offline(struct acpi_device *adev)
{
struct acpi_device_physical_node *pn;
bool offline = true;
mutex_lock(&adev->physical_node_lock);
list_for_each_entry(pn, &adev->physical_node_list, node)
if (device_supports_offline(pn->dev) && !pn->dev->offline) {
kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE);
offline = false;
break;
}
mutex_unlock(&adev->physical_node_lock);
return offline;
}
static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
void **ret_p)
{
@ -196,12 +214,11 @@ static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,
return AE_OK;
}
static int acpi_scan_hot_remove(struct acpi_device *device)
static int acpi_scan_try_to_offline(struct acpi_device *device)
{
acpi_handle handle = device->handle;
struct device *errdev;
struct device *errdev = NULL;
acpi_status status;
unsigned long long sta;
/*
* Carry out two passes here and ignore errors in the first pass,
@ -212,7 +229,6 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
*
* If the first pass is successful, the second one isn't needed, though.
*/
errdev = NULL;
status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
NULL, acpi_bus_offline, (void *)false,
(void **)&errdev);
@ -241,6 +257,23 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
return -EBUSY;
}
}
return 0;
}
static int acpi_scan_hot_remove(struct acpi_device *device)
{
acpi_handle handle = device->handle;
unsigned long long sta;
acpi_status status;
if (device->handler->hotplug.demand_offline && !acpi_force_hot_remove) {
if (!acpi_scan_is_offline(device))
return -EBUSY;
} else {
int error = acpi_scan_try_to_offline(device);
if (error)
return error;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Hot-removing device %s...\n", dev_name(&device->dev)));

3
include/acpi/acpi_bus.h
View File

@ -91,8 +91,9 @@ struct acpi_device;
struct acpi_hotplug_profile {
struct kobject kobj;
bool enabled:1;
int (*scan_dependent)(struct acpi_device *adev);
bool enabled:1;
bool demand_offline:1;
};
static inline struct acpi_hotplug_profile *to_acpi_hotplug_profile(