Messages in this thread Patch in this message | | | Date | Thu, 26 Dec 2013 12:10:04 +0900 | From | Yasuaki Ishimatsu <> | Subject | Re: [PATCH 1/2][Untested] ACPI / hotplug: Add demand_offline hotplug profile flag |
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(2013/12/23 23:00), Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > 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> > --- > drivers/acpi/scan.c | 41 +++++++++++++++++++++++++++++++++++++---- > include/acpi/acpi_bus.h | 3 ++- > 2 files changed, 39 insertions(+), 5 deletions(-) > > Index: linux-pm/drivers/acpi/scan.c > =================================================================== > --- linux-pm.orig/drivers/acpi/scan.c > +++ linux-pm/drivers/acpi/scan.c > @@ -126,6 +126,24 @@ acpi_device_modalias_show(struct device > } > 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 (!pn->dev->offline) {
Please check pn->dev->bus and pn->dev->bus->offline too as follow:
if (pn->dev->bus && pn->dev->bus->offline && !pn->dev->offline) {
My container has CPU and Memory and PCI root bridge. PCI root bridge does not has offline function (pn->dev->bus->offline). So I cannot offline the device and pn->dev->offline of the device is always 0. Therefore, following operation always returns -EBUSY even if I offline CPUs and all memory sections on a container device.
echo 0 > /sys/bus/container/devices/ACPI0004:01/online
Thanks, Yasuaki Ishimatsu
> + 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_ > 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 a > * > * 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 a > 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))); > Index: linux-pm/include/acpi/acpi_bus.h > =================================================================== > --- linux-pm.orig/include/acpi/acpi_bus.h > +++ linux-pm/include/acpi/acpi_bus.h > @@ -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( >
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