From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1428445AbeCBOBE (ORCPT ); Fri, 2 Mar 2018 09:01:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:55475 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424382AbeCBOBC (ORCPT ); Fri, 2 Mar 2018 09:01:02 -0500 Date: Fri, 2 Mar 2018 15:00:59 +0100 From: Michal Hocko To: "Lee, Chun-Yi" Cc: "Rafael J . Wysocki" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" , Len Brown Subject: Re: [PATCH] ACPI / scan: Send the change uevent with offine environmental data Message-ID: <20180302140059.GA12772@dhcp22.suse.cz> References: <20180302063508.15818-1-jlee@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180302063508.15818-1-jlee@suse.com> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 02-03-18 14:35:08, Lee, Chun-Yi wrote: > In current design of ACPI container offline, Kernel emits > KOBJ_CHANGE uevent to user space to indidate that the ejection of > the container was triggered by platform. (caa73ea15 patch) > > A pure KOBJ_CHANGE uevent is not enough for user space to identify > the purpose. For example, a "udevadm trigger" command can also > be used to emit change event to all udev rules. A udev rule can not > identify that the event is from kernel for offline or from udevadm > for other purpose. Then the offline action in udev rule may also be > triggered by udevadm tool. > > So, similar to the change uevent of dock, kernel sends the > KOBJ_CHANGE uevent with a offline environmental data to indicate > purpose. It's useful by udev rule for using ENV{EVENT} filter. Looks reasonable to me. I have also tested this on Huawei Kunlun server which hits the offline & online storm as a result of udevadm triggered and a container udev rule which hooks into change event and offlines all devices attached to the container. This patch allowed the udev rule to be more targeted at the offline event. > Cc: Michal Hocko > Cc: "Rafael J. Wysocki" > Cc: Len Brown > Signed-off-by: "Lee, Chun-Yi" Acked-by: Michal Hocko Tested-by: Michal Hocko > --- > drivers/acpi/scan.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 8e63d93..f6dca9b 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -116,6 +116,7 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent) > { > struct acpi_device_physical_node *pn; > bool offline = true; > + static const char *envp[] = { "EVENT=offline", NULL }; > > /* > * acpi_container_offline() calls this for all of the container's > @@ -126,7 +127,7 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent) > list_for_each_entry(pn, &adev->physical_node_list, node) > if (device_supports_offline(pn->dev) && !pn->dev->offline) { > if (uevent) > - kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE); > + kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp); > > offline = false; > break; > -- > 2.10.2 -- Michal Hocko SUSE Labs