From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761381Ab3EAO5v (ORCPT ); Wed, 1 May 2013 10:57:51 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:53385 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755320Ab3EAO5o (ORCPT ); Wed, 1 May 2013 10:57:44 -0400 From: "Rafael J. Wysocki" To: Toshi Kani Cc: Greg Kroah-Hartman , ACPI Devel Maling List , LKML , isimatu.yasuaki@jp.fujitsu.com, vasilis.liaskovitis@profitbricks.com Subject: Re: [PATCH 3/3 RFC] ACPI / hotplug: Use device offline/online for graceful hot-removal Date: Wed, 01 May 2013 17:05:59 +0200 Message-ID: <1513537.Pdbg9h7lkq@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.9.0+; KDE/4.9.5; x86_64; ; ) In-Reply-To: <1367365778.16154.144.camel@misato.fc.hp.com> References: <1576321.HU0tZ4cGWk@vostro.rjw.lan> <2740694.MNypEzdXxd@vostro.rjw.lan> <1367365778.16154.144.camel@misato.fc.hp.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, April 30, 2013 05:49:38 PM Toshi Kani wrote: > On Mon, 2013-04-29 at 14:29 +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > Modify the generic ACPI hotplug code to be able to check if devices > > scheduled for hot-removal may be gracefully removed from the system > > using the device offline/online mechanism introduced previously. > > > > Namely, make acpi_scan_hot_remove() which handles device hot-removal > > call device_offline() for all physical companions of the ACPI device > > nodes involved in the operation and check the results. If any of > > the device_offline() calls fails, the function will not progress to > > the removal phase (which cannot be aborted), unless its (new) force > > argument is set (in case of a failing offline it will put the devices > > offlined by it back online). > > > > In support of the 'forced' hot-removal, add a new sysfs attribute > > 'force_remove' that will reside in every ACPI hotplug profile > > present under /sys/firmware/acpi/hotplug/. > > > > Signed-off-by: Rafael J. Wysocki > > --- > > Documentation/ABI/testing/sysfs-firmware-acpi | 9 +- > > drivers/acpi/internal.h | 2 > > drivers/acpi/scan.c | 97 ++++++++++++++++++++++++-- > > drivers/acpi/sysfs.c | 27 +++++++ > > include/acpi/acpi_bus.h | 3 > > 5 files changed, 131 insertions(+), 7 deletions(-) > > > : > > Index: linux-pm/drivers/acpi/scan.c > > =================================================================== > > --- linux-pm.orig/drivers/acpi/scan.c > > +++ linux-pm/drivers/acpi/scan.c > > @@ -120,7 +120,61 @@ acpi_device_modalias_show(struct device > > } > > static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL); > > > > -static int acpi_scan_hot_remove(struct acpi_device *device) > > +static acpi_status acpi_bus_offline_companions(acpi_handle handle, u32 lvl, > > + void *data, void **ret_p) > > +{ > > + struct acpi_device *device = NULL; > > + struct acpi_device_physical_node *pn; > > + bool force = *((bool *)data); > > + acpi_status status = AE_OK; > > + > > + if (acpi_bus_get_device(handle, &device)) > > + return AE_OK; > > + > > + mutex_lock(&device->physical_node_lock); > > + > > + list_for_each_entry(pn, &device->physical_node_list, node) { > > I do not think physical_node_list is set for ACPI processor devices, so > this code is NOP at this point. I think properly initializing > physical_node_list for CPU and memblk is one of the key items in this > approach. It surely is. :-) I've almost done that for CPUs, but that still requires some more work. Hopefully, it'll be mostly done later this week. Memory will take some more time I guess, though. > > + int ret; > > + > > + ret = device_offline(pn->dev); > > + if (force) > > + continue; > > + > > + if (ret < 0) { > > + status = AE_ERROR; > > + break; > > + } > > + pn->put_online = !ret; > > + } > > + > > + mutex_unlock(&device->physical_node_lock); > > + > > + return status; > > +} > > + > > +static acpi_status acpi_bus_online_companions(acpi_handle handle, u32 lvl, > > + void *data, void **ret_p) > > +{ > > + struct acpi_device *device = NULL; > > + struct acpi_device_physical_node *pn; > > + > > + if (acpi_bus_get_device(handle, &device)) > > + return AE_OK; > > + > > + mutex_lock(&device->physical_node_lock); > > + > > + list_for_each_entry(pn, &device->physical_node_list, node) > > + if (pn->put_online) { > > + device_online(pn->dev); > > + pn->put_online = false; > > + } > > + > > + mutex_unlock(&device->physical_node_lock); > > + > > + return AE_OK; > > +} > > + > > +static int acpi_scan_hot_remove(struct acpi_device *device, bool force) > > { > > acpi_handle handle = device->handle; > > acpi_handle not_used; > > @@ -136,10 +190,30 @@ static int acpi_scan_hot_remove(struct a > > return -EINVAL; > > } > > > > + lock_device_offline(); > > + > > + status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, > > + NULL, acpi_bus_offline_companions, &force, > > + NULL); > > + if (ACPI_SUCCESS(status) || force) > > + status = acpi_bus_offline_companions(handle, 0, &force, NULL); > > + > > + if (ACPI_FAILURE(status) && !force) { > > + acpi_bus_online_companions(handle, 0, NULL, NULL); > > + acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, > > + acpi_bus_online_companions, NULL, NULL, > > + NULL); > > + unlock_device_offline(); > > Don't we need put_device(&device->dev) here? Yes, we do. Thanks for spotting that! Thanks for the comments. I'll reply to your other messages later today or tomorrow. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.