Attachment 943021 Details for Bug 1145751 – RHEL PATCH 2/2

[patch] RHEL PATCH 2/2

0002-ACPI-hotplug-driver-core-Handle-containers-in-a-spec.patch (text/plain), 10.81 KB, created by Prarit Bhargava on 2014-10-01 11:48:43 UTC

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Creator: Prarit Bhargava

Created: 2014-10-01 11:48:43 UTC

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>From 810a56adfc8e90aaef40d4b9253e2db1623fd2a9 Mon Sep 17 00:00:00 2001
>From: Prarit Bhargava <prarit@redhat.com>
>Date: Mon, 15 Sep 2014 10:45:12 -0400
>Subject: [2/6] ACPI / hotplug / driver core: Handle containers in a special
> way
>
>Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1128634
>
>commit caa73ea158de9419f08e456f2716c71d1f06012a
>Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>Date:   Sun Dec 29 15:25:48 2013 +0100
>
>    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.
>
>    Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>    Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>---
> drivers/acpi/container.c  |   48 +++++++++++++++++++++++++++++++++++++++++----
> drivers/acpi/internal.h   |    1 +
> drivers/acpi/scan.c       |    8 +++++---
> 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, 122 insertions(+), 8 deletions(-)
> create mode 100644 drivers/base/container.c
> create mode 100644 include/linux/container.h
>
>diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
>index 83d232c..0b6ae6e 100644
>--- a/drivers/acpi/container.c
>+++ b/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 container_device_ids[] = {
> 	{"", 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 container_handler = {
> 	.detach = container_device_detach,
> 	.hotplug = {
> 		.enabled = true,
>+		.demand_offline = true,
> 	},
> };
> 
>diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
>index a21c08e..4eb389f 100644
>--- a/drivers/acpi/internal.h
>+++ b/drivers/acpi/internal.h
>@@ -72,6 +72,7 @@ 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
>diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>index 4c8b2ee..a3ca7d0 100644
>--- a/drivers/acpi/scan.c
>+++ b/drivers/acpi/scan.c
>@@ -128,7 +128,7 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
> }
> 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;
>@@ -137,7 +137,9 @@ static bool acpi_scan_is_offline(struct acpi_device *adev)
> 
> 	list_for_each_entry(pn, &adev->physical_node_list, node)
> 		if (device_supports_offline(pn->dev) && !pn->dev->offline) {
>-			kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE);
>+			if (uevent)
>+				kobject_uevent(&pn->dev->kobj, KOBJ_CHANGE);
>+
> 			offline = false;
> 			break;
> 		}
>@@ -269,7 +271,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
> 	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);
>diff --git a/drivers/base/Makefile b/drivers/base/Makefile
>index 94e8a80..d08c9d3 100644
>--- a/drivers/base/Makefile
>+++ b/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/
>diff --git a/drivers/base/base.h b/drivers/base/base.h
>index 2cbc677..24f4242 100644
>--- a/drivers/base/base.h
>+++ b/drivers/base/base.h
>@@ -100,6 +100,7 @@ static inline int hypervisor_init(void) { return 0; }
> #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);
> 
>diff --git a/drivers/base/container.c b/drivers/base/container.c
>new file mode 100644
>index 0000000..ecbfbe2
>--- /dev/null
>+++ b/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);
>+}
>diff --git a/drivers/base/init.c b/drivers/base/init.c
>index c16f0b8..da033d3 100644
>--- a/drivers/base/init.c
>+++ b/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();
> }
>diff --git a/include/linux/container.h b/include/linux/container.h
>new file mode 100644
>index 0000000..3c03e6f
>--- /dev/null
>+++ b/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);
>+}
>-- 
>1.7.9.3
>

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Attachments on bug 1145751: 941540 | 941541 | 941542 | 941543 | 941544 | 941545 | 943020 | 943021 | 943022 | 943023 | 943024 | 943025 | 975178 | 975179