Re: [PATCH 1/2][Untested] ACPI / hotplug: Add demand_offline hotplug profile flag

[Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>]

(2013/12/27 9:58), Rafael J. Wysocki wrote:
> On Thursday, December 26, 2013 01:10:30 PM Yasuaki Ishimatsu wrote:
>> (2013/12/26 12:10), Yasuaki Ishimatsu wrote:
>>> (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) {
>>>
>>
>> Adding above check, I could remove container device by using eject sysfs.
>> But following messages were shown:
>
> Well, it looks like I have overlooked that error during my testing.
>
>> [ 1017.543000] ------------[ cut here ]------------
>> [ 1017.543000] WARNING: CPU: 0 PID: 6 at drivers/base/core.c:251 device_release+0x92/0xa0()
>> [ 1017.543000] Device 'ACPI0004:01' does not have a release() function, it is broken and must be fixed.
>> [ 1017.653000] Modules linked in: xt_CHECKSUM nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT ipmi_devintf ipt_REJECT cfg80211 xt_conntrack rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6
>> ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter sg ip_tables vfat fat x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support kvm_intel
>> kvm crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd dm_mirror dm_region_hash dm_log dm_mod microcode lpc_ich igb sb_edac e1000e pcspkr i2c_i801
>> [ 1017.653000]  edac_core mfd_core dca ptp pps_core shpchp ipmi_si ipmi_msghandler tpm_infineon nfsd auth_rpcgss nfs_acl lockd sunrpc xfs libcrc32c sd_mod mgag200 syscopyarea sysfillrect sysimgblt lpfc i2c_algo_bit drm_kms_helper ttm drm crc_t10dif crct10dif_common scsi_transport_fc megaraid_sas
>> i2c_core scsi_tgt
>> [ 1017.653000] CPU: 0 PID: 6 Comm: kworker/u512:0 Tainted: G        W    3.13.0-rc5+ #5
>> [ 1017.653000] Hardware name:
>> [ 1017.653000] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
>> [ 1017.653000]  0000000000000009 ffff880873a6dc68 ffffffff815d85ca ffff880873a6dcb0
>> [ 1017.653000]  ffff880873a6dca0 ffffffff8106594d ffff8a07d221c010 ffff8a07d221c000
>> [ 1017.653000]  ffff8808715472c0 ffff880871e91018 0000000000000103 ffff880873a6dd00
>> [ 1017.653000] Call Trace:
>> [ 1017.653000]  [<ffffffff815d85ca>] dump_stack+0x45/0x56
>> [ 1017.653000]  [<ffffffff8106594d>] warn_slowpath_common+0x7d/0xa0
>> [ 1017.653000]  [<ffffffff810659bc>] warn_slowpath_fmt+0x4c/0x50
>> [ 1017.653000]  [<ffffffff813ad892>] device_release+0x92/0xa0
>> [ 1017.653000]  [<ffffffff812b7197>] kobject_cleanup+0x77/0x1b0
>> [ 1017.653000]  [<ffffffff812b7045>] kobject_put+0x35/0x70
>> [ 1017.653000]  [<ffffffff813ae38c>] device_unregister+0x2c/0x60
>> [ 1017.653000]  [<ffffffff8134c87c>] container_device_detach+0x28/0x2a
>> [ 1017.653000]  [<ffffffff81323096>] acpi_bus_trim+0x56/0x89
>> [ 1017.653000]  [<ffffffff813246ae>] acpi_device_hotplug+0x168/0x383
>> [ 1017.653000]  [<ffffffff8131efba>] acpi_hotplug_work_fn+0x1c/0x27
>> [ 1017.653000]  [<ffffffff81080f1b>] process_one_work+0x17b/0x460
>> [ 1017.653000]  [<ffffffff81081ccb>] worker_thread+0x11b/0x400
>> [ 1017.653000]  [<ffffffff81081bb0>] ? rescuer_thread+0x3e0/0x3e0
>> [ 1017.653000]  [<ffffffff81088a12>] kthread+0xd2/0xf0
>> [ 1017.653000]  [<ffffffff81088940>] ? kthread_create_on_node+0x180/0x180
>> [ 1017.653000]  [<ffffffff815e82fc>] ret_from_fork+0x7c/0xb0
>> [ 1017.653000]  [<ffffffff81088940>] ? kthread_create_on_node+0x180/0x180
>> [ 1017.653000] ---[ end trace 41394323eb4b690a ]---
>
> Below is an updated version of patch [2/2] that should fix this problem (and
> the other one with the PCI host bridge not supporting offline too).

By updated patch, I can offline the container device and the above messages
disappeared.

BTW, when I hot remove PCI root bridge, following messages were shown:

...
[  116.758000] ------------[ cut here ]------------
[  116.758000] WARNING: CPU: 0 PID: 6 at fs/sysfs/group.c:214 sysfs_remove_group+0xc6/0xd0()
[  116.758000] sysfs group ffffffff819ac5c0 not found for kobject '0001:ff:10.2'
[  116.758000] Modules linked in: xt_CHECKSUM nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT ipmi_devintf ipt_REJECT xt_conntrack cfg80211 rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 
ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter ip_tables sg vfat fat x86_pkg_temp_thermal coretemp kvm_intel kvm crct10dif_pclmul 
crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd dm_mirror dm_region_hash e1000e dm_log dm_mod iTCO_wdt iTCO_vendor_support microcode sb_edac igb pcspkr edac_core i2c_i801
[  116.758000]  ptp lpc_ich pps_core dca mfd_core shpchp ipmi_si tpm_infineon ipmi_msghandler nfsd auth_rpcgss nfs_acl lockd sunrpc xfs libcrc32c sd_mod mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit drm_kms_helper lpfc ttm drm crc_t10dif crct10dif_common scsi_transport_fc megaraid_sas 
i2c_core scsi_tgt
[  116.758000] CPU: 0 PID: 6 Comm: kworker/u512:0 Tainted: G        W    3.13.0-rc5+ #11
[  116.758000] Hardware name:
[  116.758000] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
[  116.758000]  0000000000000009 ffff8808738d3bd8 ffffffff815d84ea ffff8808738d3c20
[  116.758000]  ffff8808738d3c10 ffffffff8106594d 0000000000000000 ffffffff819ac5c0
[  116.758000]  ffff880871b9d0a8 ffff8a07d1895000 0000000000000103 ffff8808738d3c70
[  116.758000] Call Trace:
[  116.758000]  [<ffffffff815d84ea>] dump_stack+0x45/0x56
[  116.758000]  [<ffffffff8106594d>] warn_slowpath_common+0x7d/0xa0
[  116.758000]  [<ffffffff810659bc>] warn_slowpath_fmt+0x4c/0x50
[  116.758000]  [<ffffffff8122b52e>] ? sysfs_get_dirent_ns+0x4e/0x70
[  116.758000]  [<ffffffff8122c806>] sysfs_remove_group+0xc6/0xd0
[  116.758000]  [<ffffffff813b83f3>] dpm_sysfs_remove+0x43/0x50
[  116.758000]  [<ffffffff813ae105>] device_del+0x45/0x1c0
[  116.758000]  [<ffffffff812e51f6>] pci_remove_bus_device+0x66/0xd0
[  116.758000]  [<ffffffff812e5363>] pci_remove_root_bus+0x73/0x80
[  116.758000]  [<ffffffff813276ab>] acpi_pci_root_remove+0x42/0x4f
[  116.758000]  [<ffffffff81323070>] acpi_bus_trim+0x56/0x89
[  116.758000]  [<ffffffff81323052>] acpi_bus_trim+0x38/0x89
[  116.758000]  [<ffffffff813245df>] acpi_device_hotplug+0x137/0x33b
[  116.758000]  [<ffffffff8131efba>] acpi_hotplug_work_fn+0x1c/0x27
[  116.758000]  [<ffffffff81080f1b>] process_one_work+0x17b/0x460
[  116.758000]  [<ffffffff81081ccb>] worker_thread+0x11b/0x400
[  116.758000]  [<ffffffff81081bb0>] ? rescuer_thread+0x3e0/0x3e0
[  116.758000]  [<ffffffff81088a12>] kthread+0xd2/0xf0
[  116.758000]  [<ffffffff81088940>] ? kthread_create_on_node+0x180/0x180
[  116.758000]  [<ffffffff815e823c>] ret_from_fork+0x7c/0xb0
[  116.758000]  [<ffffffff81088940>] ? kthread_create_on_node+0x180/0x180
[  116.758000] ---[ end trace b403db9d0ec9fc9e ]---
...

It is a know issue? The message are shown when we use latest bleeding-edge.

Thanks,
Yasuaki Ishimatsu




> Thanks,
> Rafael
>
>
> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Subject: ACPI / hotplug / driver core: Handle containers in a special way
>
> ACPI container devices require special hotplug handling, at least
> on some systems, since generally user space needs to carry out
> system-specific cleanup before it makes sense to offline devices in
> the container.  However, the current ACPI hotplug code for containers
> first attempts to offline devices in the container and only then it
> notifies user space of the container offline.
>
> Moreover, after commit 202317a573b2 (ACPI / scan: Add acpi_device
> objects for all device nodes in the namespace), ACPI device objects
> representing containers are present as long as the ACPI namespace
> nodes corresponding to them are present, which may be forever, even
> if the container devices are physically detached from the system (the
> return values of the corresponding _STA methods change in those
> cases, but generally the namespace nodes themselves are still there).
> Thus it is useful to introduce entities representing containers that
> will go away during container hot-unplug.
>
> The goal of this change is to address both the above issues.
>
> The idea is to create a "companion" container system device for each
> of the ACPI container device objects during the initial namespace
> scan or on a hotplug event making the container present.  That system
> device will be unregistered on container removal.  A new bus type
> for container devices is added for this purpose, because device
> offline and online operations need to be defined for them.  The
> online operation is a trivial function that is always successful
> and the offline uses a callback pointed to by the container device's
> offline member.
>
> For ACPI containers that callback simply walks the list of ACPI
> device objects right below the container object (its children) and
> checks if all of their physical companion devices are offline.  If
> that's not the case, it returns -EBUSY and the container system
> devivce cannot be put offline.  Consequently, to put the container
> system device offline, it is necessary to put all of the physical
> devices depending on its ACPI companion object offline beforehand.
>
> Container system devices created for ACPI container objects are
> initially online.  They are created by the container ACPI scan
> handler whose hotplug.demand_offline flag is set.  That causes
> acpi_scan_hot_remove() to check if the companion container system
> device is offline before attempting to remove an ACPI container or
> any devices below it.  If the check fails, a KOBJ_CHANGE uevent is
> emitted for the container system device in question and user space
> is expected to offline all devices below the container and the
> container itself in response to it.  Then, user space can finalize
> the removal of the container with the help of its ACPI device
> object's eject attribute in sysfs.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>   drivers/acpi/container.c  |   48 ++++++++++++++++++++++++++++++++++++++++++----
>   drivers/acpi/internal.h   |    1
>   drivers/acpi/scan.c       |   10 +++++----
>   drivers/base/Makefile     |    2 -
>   drivers/base/base.h       |    1
>   drivers/base/container.c  |   44 ++++++++++++++++++++++++++++++++++++++++++
>   drivers/base/init.c       |    1
>   include/linux/container.h |   25 +++++++++++++++++++++++
>   8 files changed, 123 insertions(+), 9 deletions(-)
>
> Index: linux-pm/include/linux/container.h
> ===================================================================
> --- /dev/null
> +++ linux-pm/include/linux/container.h
> @@ -0,0 +1,25 @@
> +/*
> + * Definitions for container bus type.
> + *
> + * Copyright (C) 2013, Intel Corporation
> + * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/device.h>
> +
> +/* drivers/base/power/container.c */
> +extern struct bus_type container_subsys;
> +
> +struct container_dev {
> +	struct device dev;
> +	int (*offline)(struct container_dev *cdev);
> +};
> +
> +static inline struct container_dev *to_container_dev(struct device *dev)
> +{
> +	return container_of(dev, struct container_dev, dev);
> +}
> Index: linux-pm/drivers/base/container.c
> ===================================================================
> --- /dev/null
> +++ linux-pm/drivers/base/container.c
> @@ -0,0 +1,44 @@
> +/*
> + * System bus type for containers.
> + *
> + * Copyright (C) 2013, Intel Corporation
> + * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/container.h>
> +
> +#include "base.h"
> +
> +#define CONTAINER_BUS_NAME	"container"
> +
> +static int trivial_online(struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static int container_offline(struct device *dev)
> +{
> +	struct container_dev *cdev = to_container_dev(dev);
> +
> +	return cdev->offline ? cdev->offline(cdev) : 0;
> +}
> +
> +struct bus_type container_subsys = {
> +	.name = CONTAINER_BUS_NAME,
> +	.dev_name = CONTAINER_BUS_NAME,
> +	.online = trivial_online,
> +	.offline = container_offline,
> +};
> +
> +void __init container_dev_init(void)
> +{
> +	int ret;
> +
> +	ret = subsys_system_register(&container_subsys, NULL);
> +	if (ret)
> +		pr_err("%s() failed: %d\n", __func__, ret);
> +}
> Index: linux-pm/drivers/base/base.h
> ===================================================================
> --- linux-pm.orig/drivers/base/base.h
> +++ linux-pm/drivers/base/base.h
> @@ -100,6 +100,7 @@ static inline int hypervisor_init(void)
>   #endif
>   extern int platform_bus_init(void);
>   extern void cpu_dev_init(void);
> +extern void container_dev_init(void);
>
>   struct kobject *virtual_device_parent(struct device *dev);
>
> Index: linux-pm/drivers/base/init.c
> ===================================================================
> --- linux-pm.orig/drivers/base/init.c
> +++ linux-pm/drivers/base/init.c
> @@ -33,4 +33,5 @@ void __init driver_init(void)
>   	platform_bus_init();
>   	cpu_dev_init();
>   	memory_dev_init();
> +	container_dev_init();
>   }
> Index: linux-pm/drivers/base/Makefile
> ===================================================================
> --- linux-pm.orig/drivers/base/Makefile
> +++ linux-pm/drivers/base/Makefile
> @@ -4,7 +4,7 @@ obj-y			:= core.o bus.o dd.o syscore.o \
>   			   driver.o class.o platform.o \
>   			   cpu.o firmware.o init.o map.o devres.o \
>   			   attribute_container.o transport_class.o \
> -			   topology.o
> +			   topology.o container.o
>   obj-$(CONFIG_DEVTMPFS)	+= devtmpfs.o
>   obj-$(CONFIG_DMA_CMA) += dma-contiguous.o
>   obj-y			+= power/
> Index: linux-pm/drivers/acpi/internal.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/internal.h
> +++ linux-pm/drivers/acpi/internal.h
> @@ -73,6 +73,7 @@ static inline void acpi_lpss_init(void)
>   #endif
>
>   bool acpi_queue_hotplug_work(struct work_struct *work);
> +bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
>
>   /* --------------------------------------------------------------------------
>                        Device Node Initialization / Removal
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -126,7 +126,7 @@ 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)
> +bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
>   {
>   	struct acpi_device_physical_node *pn;
>   	bool offline = true;
> @@ -134,8 +134,10 @@ static bool acpi_scan_is_offline(struct
>   	mutex_lock(&adev->physical_node_lock);
>
>   	list_for_each_entry(pn, &adev->physical_node_list, node)
> -		if (!pn->dev->offline) {
> -			kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE);
> +		if (device_supports_offline(pn->dev) && !pn->dev->offline) {
> +			if (uevent)
> +				kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE);
> +
>   			offline = false;
>   			break;
>   		}
> @@ -267,7 +269,7 @@ static int acpi_scan_hot_remove(struct a
>   	acpi_status status;
>
>   	if (device->handler->hotplug.demand_offline && !acpi_force_hot_remove) {
> -		if (!acpi_scan_is_offline(device))
> +		if (!acpi_scan_is_offline(device, true))
>   			return -EBUSY;
>   	} else {
>   		int error = acpi_scan_try_to_offline(device);
> Index: linux-pm/drivers/acpi/container.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/container.c
> +++ linux-pm/drivers/acpi/container.c
> @@ -27,8 +27,7 @@
>    * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    */
>   #include <linux/acpi.h>
> -
> -#include "internal.h"
> +#include <linux/container.h>
>
>   #include "internal.h"
>
> @@ -44,16 +43,56 @@ static const struct acpi_device_id conta
>   	{"", 0},
>   };
>
> +static int acpi_container_offline(struct container_dev *cdev)
> +{
> +	struct acpi_device *adev = ACPI_COMPANION(&cdev->dev);
> +	struct acpi_device *child;
> +
> +	/* Check all of the dependent devices' physical companions. */
> +	list_for_each_entry(child, &adev->children, node)
> +		if (!acpi_scan_is_offline(child, false))
> +			return -EBUSY;
> +
> +	return 0;
> +}
> +
> +static void acpi_container_release(struct device *dev)
> +{
> +	kfree(to_container_dev(dev));
> +}
> +
>   static int container_device_attach(struct acpi_device *adev,
>   				   const struct acpi_device_id *not_used)
>   {
> -	kobject_uevent(&adev->dev.kobj, KOBJ_ONLINE);
> +	struct container_dev *cdev;
> +	struct device *dev;
> +	int ret;
> +
> +	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
> +	if (!cdev)
> +		return -ENOMEM;
> +
> +	cdev->offline = acpi_container_offline;
> +	dev = &cdev->dev;
> +	dev->bus = &container_subsys;
> +	dev_set_name(dev, "%s", dev_name(&adev->dev));
> +	ACPI_COMPANION_SET(dev, adev);
> +	dev->release = acpi_container_release;
> +	ret = device_register(dev);
> +	if (ret)
> +		return ret;
> +
> +	adev->driver_data = dev;
>   	return 1;
>   }
>
>   static void container_device_detach(struct acpi_device *adev)
>   {
> -	kobject_uevent(&adev->dev.kobj, KOBJ_OFFLINE);
> +	struct device *dev = acpi_driver_data(adev);
> +
> +	adev->driver_data = NULL;
> +	if (dev)
> +		device_unregister(dev);
>   }
>
>   static struct acpi_scan_handler container_handler = {
> @@ -62,6 +101,7 @@ static struct acpi_scan_handler containe
>   	.detach = container_device_detach,
>   	.hotplug = {
>   		.enabled = true,
> +		.demand_offline = true,
>   	},
>   };
>
>