Message-ID: <4207104.v8BDjft7nT@vostro.rjw.lan>
Date:	Fri, 27 Dec 2013 01:58:29 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Toshi Kani <toshi.kani@...com>,
	Yinghai Lu <yinghai@...nel.org>,
	Zhang Rui <rui.zhang@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Aaron Lu <aaron.lu@...el.com>
Subject: Re: [PATCH 1/2][Untested] ACPI / hotplug: Add demand_offline hotplug profile flag

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@...el.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@...el.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).

Thanks,
Rafael


---
From: Rafael J. Wysocki <rafael.j.wysocki@...el.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@...el.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@...el.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@...el.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,
 	},
 };
 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists