From d22ddcbc4fb7a483d0721eddfda3f0558821d372 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 29 Dec 2013 15:25:35 +0100 Subject: 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 --- drivers/acpi/scan.c | 41 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 4 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 5383c81..65243b9 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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))); -- cgit v1.1