Patchwork [RFC,v2,10/16] ACPIHP: system device hotplug driver skeleton

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Submitter Jiang Liu
Date Aug. 4, 2012, 12:13 p.m.
Message ID <1344082443-4608-11-git-send-email-jiang.liu@huawei.com>
Download mbox | patch
Permalink /patch/175094/
State Not Applicable
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Comments

Jiang Liu - Aug. 4, 2012, 12:13 p.m.
From: Jiang Liu <jiang.liu@huawei.com>

This patch implements a skeleton for ACPI based system device hotplug driver.
This device class driver will be bound to and manage ACPI hotplug slots.

This is the default hotplug driver for ACPI based system device hotplug.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
---
 drivers/acpi/Kconfig              |   12 ++
 drivers/acpi/hotplug/Makefile     |    3 +
 drivers/acpi/hotplug/acpihp_drv.h |   62 +++++++
 drivers/acpi/hotplug/drv_main.c   |  331 +++++++++++++++++++++++++++++++++++++
 4 files changed, 408 insertions(+)
 create mode 100644 drivers/acpi/hotplug/acpihp_drv.h
 create mode 100644 drivers/acpi/hotplug/drv_main.c
Tang Chen - Aug. 9, 2012, 7:12 a.m.
Hi Liu~

I compiled this driver as a module, acpihp_drv. And when I loaded this module, it
gave the following error message:

# modprobe acpihp_drv
(the command hangs up, no return after 10 min)

#dmesg
......
[  126.643350] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
[  126.644007] IP: [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
[  126.644007] PGD 105277a067 PUD 104f823067 PMD 0 
[  126.644007] Oops: 0002 [#1] SMP 
[  126.644007] Modules linked in: acpihp_drv(+) ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle bridge stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel microcode lpc_ich mfd_core pcspkr i2c_i801 i2c_core ioatdma e1000e acpi_memhotplug i7core_edac edac_core igb dca mptsas mptscsih mptbase scsi_transport_sas
[  126.644007] CPU 10 
[  126.644007] Pid: 2821, comm: modprobe Tainted: G       A     3.6.0-rc1+ #6 FUJITSU-SV PRIMEQUEST 1800E/SB
[  126.644007] RIP: 0010:[<ffffffff814c0cd3>]  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
[  126.644007] RSP: 0018:ffff8810589a9de8  EFLAGS: 00010246
[  126.644007] RAX: 0000000000000000 RBX: 0000000000000078 RCX: 0000000000000000
[  126.644007] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000078
[  126.644007] RBP: ffff8810589a9e08 R08: 0000000000000000 R09: ffff8810589a9d88
[  126.644007] R10: 00000000000013e5 R11: 00000000000013e5 R12: ffffffffa01460d0
[  126.644007] R13: 0000000000000000 R14: ffffffffa014732b R15: 00000000000000bf
[  126.644007] FS:  00007fecb1802700(0000) GS:ffff88105e640000(0000) knlGS:0000000000000000
[  126.644007] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  126.644007] CR2: 0000000000000078 CR3: 0000001052772000 CR4: 00000000000007e0
[  126.644007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  126.644007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  126.644007] Process modprobe (pid: 2821, threadinfo ffff8810589a8000, task ffff8810592f8000)
[  126.644007] Stack:
[  126.644007]  ffff8810589a9e08 ffffffff810be37f ffffffffa0146220 ffffffff81a7b390
[  126.644007]  ffff8810589a9e58 ffffffff81317eb3 ffff8810589a9e48 0000000000000000
[  126.644007]  ffffffff81a342c0 ffffffff81a342e0 0000000000000000 ffffffffa0146220
[  126.644007] Call Trace:
[  126.644007]  [<ffffffff810be37f>] ? tracepoint_module_notify+0xd9/0x14a
[  126.644007]  [<ffffffff81317eb3>] class_interface_register+0x4a/0xbc
[  126.644007]  [<ffffffffa00b8000>] ? 0xffffffffa00b7fff
[  126.644007]  [<ffffffffa00b8010>] acpihp_drv_init+0x10/0x12 [acpihp_drv]
[  126.644007]  [<ffffffff8100207f>] do_one_initcall+0x7f/0x139
[  126.644007]  [<ffffffff81093414>] sys_init_module+0x12d3/0x14e3
[  126.644007]  [<ffffffff81264b0d>] ? ddebug_dyndbg_boot_param_cb+0x45/0x45
[  126.644007]  [<ffffffff814c9469>] system_call_fastpath+0x16/0x1b
[  126.644007] Code: 48 8b 04 25 80 c6 00 00 48 89 43 18 31 c0 5b 5b c9 c3 55 48 89 e5 53 48 83 ec 18 66 66 66 66 90 48 89 fb e8 5a 0c 00 00 48 89 df <f0> ff 0f 79 05 e8 06 ff ff ff 65 48 8b 04 25 80 c6 00 00 48 89 
[  126.644007] RIP  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
[  126.644007]  RSP <ffff8810589a9de8>
[  126.644007] CR2: 0000000000000078
[  129.981335] ---[ end trace da17e9c9de8dd560 ]---
[  139.085895] nr_pdflush_threads exported in /proc is scheduled for removal
[  139.167394] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case.  If you have one, please send an email to linux-mm@kvack.org.

Looks like it dereferenced a NULL pointer here.
May be it was my mistake that I didn't configure the environment correctly.
Would you please give me some advice ?

Thanks. :)


On 08/04/2012 08:13 PM, Jiang Liu wrote:
> From: Jiang Liu <jiang.liu@huawei.com>
> 
> This patch implements a skeleton for ACPI based system device hotplug driver.
> This device class driver will be bound to and manage ACPI hotplug slots.
> 
> This is the default hotplug driver for ACPI based system device hotplug.
> 
> Signed-off-by: Jiang Liu <liuj97@gmail.com>
> Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
> ---
>  drivers/acpi/Kconfig              |   12 ++
>  drivers/acpi/hotplug/Makefile     |    3 +
>  drivers/acpi/hotplug/acpihp_drv.h |   62 +++++++
>  drivers/acpi/hotplug/drv_main.c   |  331 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 408 insertions(+)
>  create mode 100644 drivers/acpi/hotplug/acpihp_drv.h
>  create mode 100644 drivers/acpi/hotplug/drv_main.c
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index c9f7918..89047a3 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -354,6 +354,18 @@ config ACPI_HOTPLUG_ENUM_EJ0
>  
>  	  It's the default method to detect ACPI hotplug slots.
>  
> +config ACPI_HOTPLUG_DRIVER
> +	tristate "ACPI Based System Device Hotplug Driver"
> +	depends on ACPI_HOTPLUG
> +	default y
> +	help
> +	  This driver enables ACPI based system device hotplug, including
> +	  physical processor, memory device, IO host bridge and computer
> +	  node etc.
> +
> +	  To compile this driver as a module, choose M here:
> +	  the module will be called acpihp_drv.
> +
>  config ACPI_CONTAINER
>  	tristate "Container and Module Devices (EXPERIMENTAL)"
>  	depends on EXPERIMENTAL
> diff --git a/drivers/acpi/hotplug/Makefile b/drivers/acpi/hotplug/Makefile
> index 25fac24..d69832f 100644
> --- a/drivers/acpi/hotplug/Makefile
> +++ b/drivers/acpi/hotplug/Makefile
> @@ -8,3 +8,6 @@ acpihp-y					= core.o device.o
>  obj-$(CONFIG_ACPI_HOTPLUG_ENUM)			+= acpihp_enum.o
>  acpihp_enum-y					= slot_enum.o
>  acpihp_enum-y					+= slot_enum_ej0.o
> +
> +obj-$(CONFIG_ACPI_HOTPLUG_DRIVER)		+= acpihp_drv.o
> +acpihp_drv-y					= drv_main.o
> diff --git a/drivers/acpi/hotplug/acpihp_drv.h b/drivers/acpi/hotplug/acpihp_drv.h
> new file mode 100644
> index 0000000..18330f7
> --- /dev/null
> +++ b/drivers/acpi/hotplug/acpihp_drv.h
> @@ -0,0 +1,62 @@
> +/*
> + * Copyright (C) 2011 Huawei Tech. Co., Ltd.
> + * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
> + * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + */
> +
> +#ifndef	__ACPIHP_DRV_H__
> +#define	__ACPIHP_DRV_H__
> +
> +/* Commands to change state of a hotplug slot */
> +enum acpihp_drv_cmd {
> +	ACPIHP_DRV_CMD_NOOP = 0,
> +	ACPIHP_DRV_CMD_POWERON = 0x1,
> +	ACPIHP_DRV_CMD_CONNECT = 0x2,
> +	ACPIHP_DRV_CMD_CONFIGURE = 0x4,
> +	ACPIHP_DRV_CMD_UNCONFIGURE = 0x8,
> +	ACPIHP_DRV_CMD_DISCONNECT = 0x10,
> +	ACPIHP_DRV_CMD_POWEROFF = 0x20,
> +	ACPIHP_DRV_CMD_CANCEL = 0x40,
> +	ACPIHP_DRV_CMD_MAX
> +};
> +
> +/* Hotplug operations may be triggered by firmware or OS */
> +enum acpihp_dev_event {
> +	ACPIHP_DRV_EVENT_FROM_FW,
> +	ACPIHP_DRV_EVENT_FROM_OS
> +};
> +
> +struct acpihp_slot_drv {
> +	enum acpihp_dev_event	event_flag;
> +	struct mutex		op_mutex; /* Prevent concurrent hotplugs. */
> +	struct list_head	depend_list; /* Dependency relationship */
> +	atomic_t		cancel_status;
> +	atomic_t		cancel_flag;
> +	struct acpihp_cancel_context	cancel_ctx;
> +};
> +
> +void acpihp_drv_get_data(struct acpihp_slot *slot,
> +			 struct acpihp_slot_drv **data);
> +int acpihp_drv_enumerate_devices(struct acpihp_slot *slot);
> +void acpihp_drv_update_slot_state(struct acpihp_slot *slot);
> +int acpihp_drv_update_slot_status(struct acpihp_slot *slot);
> +
> +#endif	/* __ACPIHP_DRV_H__ */
> diff --git a/drivers/acpi/hotplug/drv_main.c b/drivers/acpi/hotplug/drv_main.c
> new file mode 100644
> index 0000000..538772d
> --- /dev/null
> +++ b/drivers/acpi/hotplug/drv_main.c
> @@ -0,0 +1,331 @@
> +/*
> + * Copyright (C) 2011 Huawei Tech. Co., Ltd.
> + * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
> + * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <linux/kthread.h>
> +#include <linux/delay.h>
> +#include <linux/acpi.h>
> +#include <acpi/acpi_hotplug.h>
> +#include "acpihp_drv.h"
> +
> +static struct class_interface acpihp_drv_interface;
> +
> +void acpihp_drv_get_data(struct acpihp_slot *slot,
> +			 struct acpihp_slot_drv **data)
> +{
> +	*data = NULL;
> +	acpihp_slot_get_drv_data(slot, &acpihp_drv_interface, (void **)data);
> +}
> +
> +/* Update slot state according to state of devices connecting to it. */
> +void acpihp_drv_update_slot_state(struct acpihp_slot *slot)
> +{
> +	enum acpihp_dev_type type;
> +	enum acpihp_slot_state state;
> +	struct klist_iter iter;
> +	struct klist_node *ip;
> +	struct acpihp_dev_node *dp;
> +	bool connected = false;
> +	bool configured = false;
> +
> +	if (!acpihp_slot_present(slot)) {
> +		state = ACPIHP_SLOT_STATE_ABSENT;
> +		goto out;
> +	} else if (!acpihp_slot_powered(slot)) {
> +		state = ACPIHP_SLOT_STATE_PRESENT;
> +		goto out;
> +	}
> +
> +	for (type = ACPIHP_DEV_TYPE_UNKNOWN;
> +	     type < ACPIHP_DEV_TYPE_MAX && !configured;
> +	     type++) {
> +		klist_iter_init(&slot->dev_lists[type], &iter);
> +		while ((ip = klist_next(&iter)) != NULL) {
> +			connected = true;
> +			dp = container_of(ip, struct acpihp_dev_node, node);
> +			if (dp->state == DEVICE_STATE_CONFIGURED) {
> +				configured = true;
> +				break;
> +			}
> +		}
> +		klist_iter_exit(&iter);
> +	}
> +
> +	if (configured)
> +		state = ACPIHP_SLOT_STATE_CONFIGURED;
> +	else if (connected)
> +		state = ACPIHP_SLOT_STATE_CONNECTED;
> +	else
> +		state = ACPIHP_SLOT_STATE_POWERED;
> +
> +out:
> +	acpihp_slot_change_state(slot, state);
> +}
> +
> +/* Update slot state according to status of devices connecting to it. */
> +int acpihp_drv_update_slot_status(struct acpihp_slot *slot)
> +{
> +	int ret = 0;
> +	enum acpihp_dev_type type;
> +	struct klist_iter iter;
> +	struct klist_node *ip;
> +	struct acpihp_dev_node *np;
> +	struct acpi_device *dev;
> +	struct acpihp_dev_info *info;
> +
> +	if (!slot)
> +		return -EINVAL;
> +
> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	for (type = ACPIHP_DEV_TYPE_MEM; type <= ACPIHP_DEV_TYPE_HOST_BRIDGE;
> +	     type++) {
> +		klist_iter_init(&slot->dev_lists[type], &iter);
> +		while ((ip = klist_next(&iter)) != NULL) {
> +			np = container_of(ip, struct acpihp_dev_node, node);
> +			dev = container_of(np->dev, struct acpi_device, dev);
> +			ret = acpihp_dev_get_info(dev, info);
> +			if (ret) {
> +				ACPIHP_DEBUG("fails to get info about %s.\n",
> +					     dev_name(&dev->dev));
> +				goto out;
> +			}
> +
> +			if (info->status & ACPIHP_DEV_STATUS_FAULT)
> +				acpihp_slot_set_flag(slot,
> +						ACPIHP_SLOT_FLAG_FAULT);
> +			if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
> +				acpihp_slot_set_flag(slot,
> +						ACPIHP_SLOT_FLAG_IRREMOVABLE);
> +		}
> +	}
> +
> +out:
> +	kfree(info);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(acpihp_drv_update_slot_status);
> +
> +/* Add ACPI device to hotplug slot's device list */
> +static acpi_status acpihp_drv_enum_device(struct acpi_device *dev, void *argp)
> +{
> +	int ret = -ENOMEM;
> +	acpi_status rv = AE_OK;
> +	enum acpihp_dev_type type;
> +	enum acpihp_dev_state state;
> +	struct acpihp_dev_info *info;
> +	struct acpihp_slot *slot = (struct acpihp_slot *)argp;
> +
> +	if (acpihp_dev_get_type(dev->handle, &type)) {
> +		ACPIHP_DEBUG("fails to get device type of %s.\n",
> +			     dev_name(&dev->dev));
> +		return AE_ERROR;
> +	} else if (type == ACPIHP_DEV_TYPE_MAX) {
> +		/*
> +		 * Some ACPI objects for IO devices, such as PCI/IDE etc, only
> +		 * implement _ADR instead of _HID/_CID, skip them.
> +		 */
> +		return AE_CTRL_DEPTH;
> +	}
> +
> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> +	if (info)
> +		ret = acpihp_dev_get_info(dev, info);
> +
> +	if (!ret) {
> +		if (info->status & ACPIHP_DEV_STATUS_STARTED)
> +			state = DEVICE_STATE_CONFIGURED;
> +		else
> +			state = DEVICE_STATE_CONNECTED;
> +
> +		if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
> +			acpihp_slot_set_flag(slot,
> +					     ACPIHP_SLOT_FLAG_IRREMOVABLE);
> +		if (info->status & ACPIHP_DEV_STATUS_FAULT)
> +			acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_FAULT);
> +
> +		if (acpihp_slot_add_device(slot, type, state, &dev->dev)) {
> +			ACPIHP_DEBUG("fails to add %s to slot %s.\n",
> +				     dev_name(&dev->dev), slot->name);
> +			rv = AE_ERROR;
> +		}
> +	} else {
> +		ACPIHP_DEBUG("fails to query device info of %s.\n",
> +			     dev_name(&dev->dev));
> +	}
> +
> +	kfree(info);
> +
> +	return rv;
> +}
> +
> +/*
> + * Enumerator all devices connecting to a slot and add them onto slot's
> + * device lists.
> + */
> +int acpihp_drv_enumerate_devices(struct acpihp_slot *slot)
> +{
> +	return acpihp_walk_devices(slot->handle, acpihp_drv_enum_device, slot);
> +}
> +
> +static void acpihp_drv_remove_devices(struct acpihp_slot *slot)
> +{
> +	enum acpihp_dev_type type;
> +
> +	for (type = ACPIHP_DEV_TYPE_UNKNOWN; type < ACPIHP_DEV_TYPE_MAX; type++)
> +		acpihp_remove_device_list(&slot->dev_lists[type]);
> +}
> +
> +/* Callback function for ACPI system event notification. */
> +static void acpihp_drv_event_handler(acpi_handle handle, u32 event,
> +				     void *context)
> +{
> +	/* TODO: handle ACPI hotplug events */
> +}
> +
> +static acpi_status acpihp_drv_install_handler(struct acpihp_slot *slot)
> +{
> +	acpi_status status;
> +
> +	status = acpi_install_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
> +					     acpihp_drv_event_handler, slot);
> +	ACPIHP_DEBUG("%s to install event handler for %s.\n",
> +		     ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
> +
> +	return status;
> +}
> +
> +static void acpihp_drv_uninstall_handler(struct acpihp_slot *slot)
> +{
> +	acpi_status status;
> +
> +	status = acpi_remove_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
> +					    acpihp_drv_event_handler);
> +	ACPIHP_DEBUG("%s to uninstall event handler for %s.\n",
> +		ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
> +}
> +
> +static int acpihp_drv_slot_add(struct device *dev, struct class_interface *intf)
> +{
> +	struct acpihp_slot_drv *drv_data;
> +	struct acpihp_slot *slot = container_of(dev, struct acpihp_slot, dev);
> +
> +	/*
> +	 * Try to hold a reference to the slot_ops structure to prevent
> +	 * the platform specific enumerator driver from unloading.
> +	 */
> +	if (!slot->slot_ops || !try_module_get(slot->slot_ops->owner)) {
> +		ACPIHP_DEBUG("fails to get reference to slot_ops for %s.\n",
> +			     slot->name);
> +		return -EINVAL;
> +	}
> +
> +	/* install ACPI event notification handler for slot */
> +	if (ACPI_FAILURE(acpihp_drv_install_handler(slot))) {
> +		ACPIHP_DEBUG("fails to install event handler for %s.\n",
> +			     slot->name);
> +		module_put(slot->slot_ops->owner);
> +		return -EBUSY;
> +	}
> +
> +	/* Enumerate all devices if slot is already powered. */
> +	if (!acpihp_slot_powered(slot))
> +		ACPIHP_DEBUG("slot %s is powered off.\n", slot->name);
> +	else if (acpihp_drv_enumerate_devices(slot))
> +		acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_IRREMOVABLE);
> +
> +	acpihp_drv_update_slot_state(slot);
> +
> +	drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
> +	if (drv_data) {
> +		drv_data->event_flag = ACPIHP_DRV_EVENT_FROM_FW;
> +		mutex_init(&drv_data->op_mutex);
> +		INIT_LIST_HEAD(&drv_data->depend_list);
> +	}
> +	if (drv_data == NULL ||
> +	    acpihp_slot_attach_drv_data(slot, intf, (void *)drv_data)) {
> +		ACPIHP_DEBUG("fails to attach driver data for %s.\n",
> +			     slot->name);
> +		acpihp_drv_remove_devices(slot);
> +		module_put(slot->slot_ops->owner);
> +		kfree(drv_data);
> +		return -ENOMEM;
> +	}
> +
> +	ACPIHP_INFO("found hotplug slot %s.\n", slot->full_path);
> +
> +	return 0;
> +}
> +
> +static void acpihp_drv_intf_remove(struct device *dev,
> +				  struct class_interface *intf)
> +{
> +	struct acpihp_slot_drv *drv_data = NULL;
> +	struct acpihp_slot *slot =
> +			container_of(dev, struct acpihp_slot, dev);
> +
> +	ACPIHP_INFO("remove hotplug slot %s.\n", slot->full_path);
> +
> +	acpihp_drv_uninstall_handler(slot);
> +	acpihp_drv_remove_devices(slot);
> +	acpihp_slot_detach_drv_data(slot, intf, (void **)&drv_data);
> +	if (drv_data != NULL)
> +		kfree(drv_data);
> +
> +	module_put(slot->slot_ops->owner);
> +}
> +
> +/*
> + * register a class driver onto the acpihp_slot_class to manage all system
> + * device hotplug slots.
> + */
> +static struct class_interface acpihp_drv_interface = {
> +	.class		= &acpihp_slot_class,
> +	.add_dev	= acpihp_drv_slot_add,
> +	.remove_dev	= acpihp_drv_intf_remove,
> +};
> +
> +static int __init acpihp_drv_init(void)
> +{
> +	return class_interface_register(&acpihp_drv_interface);
> +}
> +
> +static void __exit acpihp_drv_exit(void)
> +{
> +	class_interface_unregister(&acpihp_drv_interface);
> +}
> +
> +module_init(acpihp_drv_init);
> +module_exit(acpihp_drv_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Jiang Liu <jiang.liu@huawei.com>");
> +MODULE_AUTHOR("Hanjun Guo <guohanjun@huawei.com>");
Jiang Liu - Aug. 9, 2012, 7:40 a.m.
Hi Tang,
	Thanks for testing.
	Currently there's a limitation that you need to insert acpihp_enum driver first.
Will fix this issue in next version.
	Regards!
	Gerry

On 2012-8-9 15:12, Tang Chen wrote:
> Hi Liu~
> 
> I compiled this driver as a module, acpihp_drv. And when I loaded this module, it
> gave the following error message:
> 
> # modprobe acpihp_drv
> (the command hangs up, no return after 10 min)
> 
> #dmesg
> ......
> [  126.643350] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
> [  126.644007] IP: [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
> [  126.644007] PGD 105277a067 PUD 104f823067 PMD 0 
> [  126.644007] Oops: 0002 [#1] SMP 
> [  126.644007] Modules linked in: acpihp_drv(+) ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle bridge stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel microcode lpc_ich mfd_core pcspkr i2c_i801 i2c_core ioatdma e1000e acpi_memhotplug i7core_edac edac_core igb dca mptsas mptscsih mptbase scsi_transport_sas
> [  126.644007] CPU 10 
> [  126.644007] Pid: 2821, comm: modprobe Tainted: G       A     3.6.0-rc1+ #6 FUJITSU-SV PRIMEQUEST 1800E/SB
> [  126.644007] RIP: 0010:[<ffffffff814c0cd3>]  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
> [  126.644007] RSP: 0018:ffff8810589a9de8  EFLAGS: 00010246
> [  126.644007] RAX: 0000000000000000 RBX: 0000000000000078 RCX: 0000000000000000
> [  126.644007] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000078
> [  126.644007] RBP: ffff8810589a9e08 R08: 0000000000000000 R09: ffff8810589a9d88
> [  126.644007] R10: 00000000000013e5 R11: 00000000000013e5 R12: ffffffffa01460d0
> [  126.644007] R13: 0000000000000000 R14: ffffffffa014732b R15: 00000000000000bf
> [  126.644007] FS:  00007fecb1802700(0000) GS:ffff88105e640000(0000) knlGS:0000000000000000
> [  126.644007] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  126.644007] CR2: 0000000000000078 CR3: 0000001052772000 CR4: 00000000000007e0
> [  126.644007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  126.644007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [  126.644007] Process modprobe (pid: 2821, threadinfo ffff8810589a8000, task ffff8810592f8000)
> [  126.644007] Stack:
> [  126.644007]  ffff8810589a9e08 ffffffff810be37f ffffffffa0146220 ffffffff81a7b390
> [  126.644007]  ffff8810589a9e58 ffffffff81317eb3 ffff8810589a9e48 0000000000000000
> [  126.644007]  ffffffff81a342c0 ffffffff81a342e0 0000000000000000 ffffffffa0146220
> [  126.644007] Call Trace:
> [  126.644007]  [<ffffffff810be37f>] ? tracepoint_module_notify+0xd9/0x14a
> [  126.644007]  [<ffffffff81317eb3>] class_interface_register+0x4a/0xbc
> [  126.644007]  [<ffffffffa00b8000>] ? 0xffffffffa00b7fff
> [  126.644007]  [<ffffffffa00b8010>] acpihp_drv_init+0x10/0x12 [acpihp_drv]
> [  126.644007]  [<ffffffff8100207f>] do_one_initcall+0x7f/0x139
> [  126.644007]  [<ffffffff81093414>] sys_init_module+0x12d3/0x14e3
> [  126.644007]  [<ffffffff81264b0d>] ? ddebug_dyndbg_boot_param_cb+0x45/0x45
> [  126.644007]  [<ffffffff814c9469>] system_call_fastpath+0x16/0x1b
> [  126.644007] Code: 48 8b 04 25 80 c6 00 00 48 89 43 18 31 c0 5b 5b c9 c3 55 48 89 e5 53 48 83 ec 18 66 66 66 66 90 48 89 fb e8 5a 0c 00 00 48 89 df <f0> ff 0f 79 05 e8 06 ff ff ff 65 48 8b 04 25 80 c6 00 00 48 89 
> [  126.644007] RIP  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
> [  126.644007]  RSP <ffff8810589a9de8>
> [  126.644007] CR2: 0000000000000078
> [  129.981335] ---[ end trace da17e9c9de8dd560 ]---
> [  139.085895] nr_pdflush_threads exported in /proc is scheduled for removal
> [  139.167394] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case.  If you have one, please send an email to linux-mm@kvack.org.
> 
> Looks like it dereferenced a NULL pointer here.
> May be it was my mistake that I didn't configure the environment correctly.
> Would you please give me some advice ?
> 
> Thanks. :)
> 
> 
> On 08/04/2012 08:13 PM, Jiang Liu wrote:
>> From: Jiang Liu <jiang.liu@huawei.com>
>>
>> This patch implements a skeleton for ACPI based system device hotplug driver.
>> This device class driver will be bound to and manage ACPI hotplug slots.
>>
>> This is the default hotplug driver for ACPI based system device hotplug.
>>
>> Signed-off-by: Jiang Liu <liuj97@gmail.com>
>> Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
>> ---
>>  drivers/acpi/Kconfig              |   12 ++
>>  drivers/acpi/hotplug/Makefile     |    3 +
>>  drivers/acpi/hotplug/acpihp_drv.h |   62 +++++++
>>  drivers/acpi/hotplug/drv_main.c   |  331 +++++++++++++++++++++++++++++++++++++
>>  4 files changed, 408 insertions(+)
>>  create mode 100644 drivers/acpi/hotplug/acpihp_drv.h
>>  create mode 100644 drivers/acpi/hotplug/drv_main.c
>>
>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>> index c9f7918..89047a3 100644
>> --- a/drivers/acpi/Kconfig
>> +++ b/drivers/acpi/Kconfig
>> @@ -354,6 +354,18 @@ config ACPI_HOTPLUG_ENUM_EJ0
>>  
>>  	  It's the default method to detect ACPI hotplug slots.
>>  
>> +config ACPI_HOTPLUG_DRIVER
>> +	tristate "ACPI Based System Device Hotplug Driver"
>> +	depends on ACPI_HOTPLUG
>> +	default y
>> +	help
>> +	  This driver enables ACPI based system device hotplug, including
>> +	  physical processor, memory device, IO host bridge and computer
>> +	  node etc.
>> +
>> +	  To compile this driver as a module, choose M here:
>> +	  the module will be called acpihp_drv.
>> +
>>  config ACPI_CONTAINER
>>  	tristate "Container and Module Devices (EXPERIMENTAL)"
>>  	depends on EXPERIMENTAL
>> diff --git a/drivers/acpi/hotplug/Makefile b/drivers/acpi/hotplug/Makefile
>> index 25fac24..d69832f 100644
>> --- a/drivers/acpi/hotplug/Makefile
>> +++ b/drivers/acpi/hotplug/Makefile
>> @@ -8,3 +8,6 @@ acpihp-y					= core.o device.o
>>  obj-$(CONFIG_ACPI_HOTPLUG_ENUM)			+= acpihp_enum.o
>>  acpihp_enum-y					= slot_enum.o
>>  acpihp_enum-y					+= slot_enum_ej0.o
>> +
>> +obj-$(CONFIG_ACPI_HOTPLUG_DRIVER)		+= acpihp_drv.o
>> +acpihp_drv-y					= drv_main.o
>> diff --git a/drivers/acpi/hotplug/acpihp_drv.h b/drivers/acpi/hotplug/acpihp_drv.h
>> new file mode 100644
>> index 0000000..18330f7
>> --- /dev/null
>> +++ b/drivers/acpi/hotplug/acpihp_drv.h
>> @@ -0,0 +1,62 @@
>> +/*
>> + * Copyright (C) 2011 Huawei Tech. Co., Ltd.
>> + * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
>> + * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + */
>> +
>> +#ifndef	__ACPIHP_DRV_H__
>> +#define	__ACPIHP_DRV_H__
>> +
>> +/* Commands to change state of a hotplug slot */
>> +enum acpihp_drv_cmd {
>> +	ACPIHP_DRV_CMD_NOOP = 0,
>> +	ACPIHP_DRV_CMD_POWERON = 0x1,
>> +	ACPIHP_DRV_CMD_CONNECT = 0x2,
>> +	ACPIHP_DRV_CMD_CONFIGURE = 0x4,
>> +	ACPIHP_DRV_CMD_UNCONFIGURE = 0x8,
>> +	ACPIHP_DRV_CMD_DISCONNECT = 0x10,
>> +	ACPIHP_DRV_CMD_POWEROFF = 0x20,
>> +	ACPIHP_DRV_CMD_CANCEL = 0x40,
>> +	ACPIHP_DRV_CMD_MAX
>> +};
>> +
>> +/* Hotplug operations may be triggered by firmware or OS */
>> +enum acpihp_dev_event {
>> +	ACPIHP_DRV_EVENT_FROM_FW,
>> +	ACPIHP_DRV_EVENT_FROM_OS
>> +};
>> +
>> +struct acpihp_slot_drv {
>> +	enum acpihp_dev_event	event_flag;
>> +	struct mutex		op_mutex; /* Prevent concurrent hotplugs. */
>> +	struct list_head	depend_list; /* Dependency relationship */
>> +	atomic_t		cancel_status;
>> +	atomic_t		cancel_flag;
>> +	struct acpihp_cancel_context	cancel_ctx;
>> +};
>> +
>> +void acpihp_drv_get_data(struct acpihp_slot *slot,
>> +			 struct acpihp_slot_drv **data);
>> +int acpihp_drv_enumerate_devices(struct acpihp_slot *slot);
>> +void acpihp_drv_update_slot_state(struct acpihp_slot *slot);
>> +int acpihp_drv_update_slot_status(struct acpihp_slot *slot);
>> +
>> +#endif	/* __ACPIHP_DRV_H__ */
>> diff --git a/drivers/acpi/hotplug/drv_main.c b/drivers/acpi/hotplug/drv_main.c
>> new file mode 100644
>> index 0000000..538772d
>> --- /dev/null
>> +++ b/drivers/acpi/hotplug/drv_main.c
>> @@ -0,0 +1,331 @@
>> +/*
>> + * Copyright (C) 2011 Huawei Tech. Co., Ltd.
>> + * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
>> + * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/errno.h>
>> +#include <linux/types.h>
>> +#include <linux/list.h>
>> +#include <linux/mutex.h>
>> +#include <linux/kthread.h>
>> +#include <linux/delay.h>
>> +#include <linux/acpi.h>
>> +#include <acpi/acpi_hotplug.h>
>> +#include "acpihp_drv.h"
>> +
>> +static struct class_interface acpihp_drv_interface;
>> +
>> +void acpihp_drv_get_data(struct acpihp_slot *slot,
>> +			 struct acpihp_slot_drv **data)
>> +{
>> +	*data = NULL;
>> +	acpihp_slot_get_drv_data(slot, &acpihp_drv_interface, (void **)data);
>> +}
>> +
>> +/* Update slot state according to state of devices connecting to it. */
>> +void acpihp_drv_update_slot_state(struct acpihp_slot *slot)
>> +{
>> +	enum acpihp_dev_type type;
>> +	enum acpihp_slot_state state;
>> +	struct klist_iter iter;
>> +	struct klist_node *ip;
>> +	struct acpihp_dev_node *dp;
>> +	bool connected = false;
>> +	bool configured = false;
>> +
>> +	if (!acpihp_slot_present(slot)) {
>> +		state = ACPIHP_SLOT_STATE_ABSENT;
>> +		goto out;
>> +	} else if (!acpihp_slot_powered(slot)) {
>> +		state = ACPIHP_SLOT_STATE_PRESENT;
>> +		goto out;
>> +	}
>> +
>> +	for (type = ACPIHP_DEV_TYPE_UNKNOWN;
>> +	     type < ACPIHP_DEV_TYPE_MAX && !configured;
>> +	     type++) {
>> +		klist_iter_init(&slot->dev_lists[type], &iter);
>> +		while ((ip = klist_next(&iter)) != NULL) {
>> +			connected = true;
>> +			dp = container_of(ip, struct acpihp_dev_node, node);
>> +			if (dp->state == DEVICE_STATE_CONFIGURED) {
>> +				configured = true;
>> +				break;
>> +			}
>> +		}
>> +		klist_iter_exit(&iter);
>> +	}
>> +
>> +	if (configured)
>> +		state = ACPIHP_SLOT_STATE_CONFIGURED;
>> +	else if (connected)
>> +		state = ACPIHP_SLOT_STATE_CONNECTED;
>> +	else
>> +		state = ACPIHP_SLOT_STATE_POWERED;
>> +
>> +out:
>> +	acpihp_slot_change_state(slot, state);
>> +}
>> +
>> +/* Update slot state according to status of devices connecting to it. */
>> +int acpihp_drv_update_slot_status(struct acpihp_slot *slot)
>> +{
>> +	int ret = 0;
>> +	enum acpihp_dev_type type;
>> +	struct klist_iter iter;
>> +	struct klist_node *ip;
>> +	struct acpihp_dev_node *np;
>> +	struct acpi_device *dev;
>> +	struct acpihp_dev_info *info;
>> +
>> +	if (!slot)
>> +		return -EINVAL;
>> +
>> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
>> +	if (!info)
>> +		return -ENOMEM;
>> +
>> +	for (type = ACPIHP_DEV_TYPE_MEM; type <= ACPIHP_DEV_TYPE_HOST_BRIDGE;
>> +	     type++) {
>> +		klist_iter_init(&slot->dev_lists[type], &iter);
>> +		while ((ip = klist_next(&iter)) != NULL) {
>> +			np = container_of(ip, struct acpihp_dev_node, node);
>> +			dev = container_of(np->dev, struct acpi_device, dev);
>> +			ret = acpihp_dev_get_info(dev, info);
>> +			if (ret) {
>> +				ACPIHP_DEBUG("fails to get info about %s.\n",
>> +					     dev_name(&dev->dev));
>> +				goto out;
>> +			}
>> +
>> +			if (info->status & ACPIHP_DEV_STATUS_FAULT)
>> +				acpihp_slot_set_flag(slot,
>> +						ACPIHP_SLOT_FLAG_FAULT);
>> +			if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
>> +				acpihp_slot_set_flag(slot,
>> +						ACPIHP_SLOT_FLAG_IRREMOVABLE);
>> +		}
>> +	}
>> +
>> +out:
>> +	kfree(info);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(acpihp_drv_update_slot_status);
>> +
>> +/* Add ACPI device to hotplug slot's device list */
>> +static acpi_status acpihp_drv_enum_device(struct acpi_device *dev, void *argp)
>> +{
>> +	int ret = -ENOMEM;
>> +	acpi_status rv = AE_OK;
>> +	enum acpihp_dev_type type;
>> +	enum acpihp_dev_state state;
>> +	struct acpihp_dev_info *info;
>> +	struct acpihp_slot *slot = (struct acpihp_slot *)argp;
>> +
>> +	if (acpihp_dev_get_type(dev->handle, &type)) {
>> +		ACPIHP_DEBUG("fails to get device type of %s.\n",
>> +			     dev_name(&dev->dev));
>> +		return AE_ERROR;
>> +	} else if (type == ACPIHP_DEV_TYPE_MAX) {
>> +		/*
>> +		 * Some ACPI objects for IO devices, such as PCI/IDE etc, only
>> +		 * implement _ADR instead of _HID/_CID, skip them.
>> +		 */
>> +		return AE_CTRL_DEPTH;
>> +	}
>> +
>> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
>> +	if (info)
>> +		ret = acpihp_dev_get_info(dev, info);
>> +
>> +	if (!ret) {
>> +		if (info->status & ACPIHP_DEV_STATUS_STARTED)
>> +			state = DEVICE_STATE_CONFIGURED;
>> +		else
>> +			state = DEVICE_STATE_CONNECTED;
>> +
>> +		if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
>> +			acpihp_slot_set_flag(slot,
>> +					     ACPIHP_SLOT_FLAG_IRREMOVABLE);
>> +		if (info->status & ACPIHP_DEV_STATUS_FAULT)
>> +			acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_FAULT);
>> +
>> +		if (acpihp_slot_add_device(slot, type, state, &dev->dev)) {
>> +			ACPIHP_DEBUG("fails to add %s to slot %s.\n",
>> +				     dev_name(&dev->dev), slot->name);
>> +			rv = AE_ERROR;
>> +		}
>> +	} else {
>> +		ACPIHP_DEBUG("fails to query device info of %s.\n",
>> +			     dev_name(&dev->dev));
>> +	}
>> +
>> +	kfree(info);
>> +
>> +	return rv;
>> +}
>> +
>> +/*
>> + * Enumerator all devices connecting to a slot and add them onto slot's
>> + * device lists.
>> + */
>> +int acpihp_drv_enumerate_devices(struct acpihp_slot *slot)
>> +{
>> +	return acpihp_walk_devices(slot->handle, acpihp_drv_enum_device, slot);
>> +}
>> +
>> +static void acpihp_drv_remove_devices(struct acpihp_slot *slot)
>> +{
>> +	enum acpihp_dev_type type;
>> +
>> +	for (type = ACPIHP_DEV_TYPE_UNKNOWN; type < ACPIHP_DEV_TYPE_MAX; type++)
>> +		acpihp_remove_device_list(&slot->dev_lists[type]);
>> +}
>> +
>> +/* Callback function for ACPI system event notification. */
>> +static void acpihp_drv_event_handler(acpi_handle handle, u32 event,
>> +				     void *context)
>> +{
>> +	/* TODO: handle ACPI hotplug events */
>> +}
>> +
>> +static acpi_status acpihp_drv_install_handler(struct acpihp_slot *slot)
>> +{
>> +	acpi_status status;
>> +
>> +	status = acpi_install_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
>> +					     acpihp_drv_event_handler, slot);
>> +	ACPIHP_DEBUG("%s to install event handler for %s.\n",
>> +		     ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
>> +
>> +	return status;
>> +}
>> +
>> +static void acpihp_drv_uninstall_handler(struct acpihp_slot *slot)
>> +{
>> +	acpi_status status;
>> +
>> +	status = acpi_remove_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
>> +					    acpihp_drv_event_handler);
>> +	ACPIHP_DEBUG("%s to uninstall event handler for %s.\n",
>> +		ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
>> +}
>> +
>> +static int acpihp_drv_slot_add(struct device *dev, struct class_interface *intf)
>> +{
>> +	struct acpihp_slot_drv *drv_data;
>> +	struct acpihp_slot *slot = container_of(dev, struct acpihp_slot, dev);
>> +
>> +	/*
>> +	 * Try to hold a reference to the slot_ops structure to prevent
>> +	 * the platform specific enumerator driver from unloading.
>> +	 */
>> +	if (!slot->slot_ops || !try_module_get(slot->slot_ops->owner)) {
>> +		ACPIHP_DEBUG("fails to get reference to slot_ops for %s.\n",
>> +			     slot->name);
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* install ACPI event notification handler for slot */
>> +	if (ACPI_FAILURE(acpihp_drv_install_handler(slot))) {
>> +		ACPIHP_DEBUG("fails to install event handler for %s.\n",
>> +			     slot->name);
>> +		module_put(slot->slot_ops->owner);
>> +		return -EBUSY;
>> +	}
>> +
>> +	/* Enumerate all devices if slot is already powered. */
>> +	if (!acpihp_slot_powered(slot))
>> +		ACPIHP_DEBUG("slot %s is powered off.\n", slot->name);
>> +	else if (acpihp_drv_enumerate_devices(slot))
>> +		acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_IRREMOVABLE);
>> +
>> +	acpihp_drv_update_slot_state(slot);
>> +
>> +	drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
>> +	if (drv_data) {
>> +		drv_data->event_flag = ACPIHP_DRV_EVENT_FROM_FW;
>> +		mutex_init(&drv_data->op_mutex);
>> +		INIT_LIST_HEAD(&drv_data->depend_list);
>> +	}
>> +	if (drv_data == NULL ||
>> +	    acpihp_slot_attach_drv_data(slot, intf, (void *)drv_data)) {
>> +		ACPIHP_DEBUG("fails to attach driver data for %s.\n",
>> +			     slot->name);
>> +		acpihp_drv_remove_devices(slot);
>> +		module_put(slot->slot_ops->owner);
>> +		kfree(drv_data);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	ACPIHP_INFO("found hotplug slot %s.\n", slot->full_path);
>> +
>> +	return 0;
>> +}
>> +
>> +static void acpihp_drv_intf_remove(struct device *dev,
>> +				  struct class_interface *intf)
>> +{
>> +	struct acpihp_slot_drv *drv_data = NULL;
>> +	struct acpihp_slot *slot =
>> +			container_of(dev, struct acpihp_slot, dev);
>> +
>> +	ACPIHP_INFO("remove hotplug slot %s.\n", slot->full_path);
>> +
>> +	acpihp_drv_uninstall_handler(slot);
>> +	acpihp_drv_remove_devices(slot);
>> +	acpihp_slot_detach_drv_data(slot, intf, (void **)&drv_data);
>> +	if (drv_data != NULL)
>> +		kfree(drv_data);
>> +
>> +	module_put(slot->slot_ops->owner);
>> +}
>> +
>> +/*
>> + * register a class driver onto the acpihp_slot_class to manage all system
>> + * device hotplug slots.
>> + */
>> +static struct class_interface acpihp_drv_interface = {
>> +	.class		= &acpihp_slot_class,
>> +	.add_dev	= acpihp_drv_slot_add,
>> +	.remove_dev	= acpihp_drv_intf_remove,
>> +};
>> +
>> +static int __init acpihp_drv_init(void)
>> +{
>> +	return class_interface_register(&acpihp_drv_interface);
>> +}
>> +
>> +static void __exit acpihp_drv_exit(void)
>> +{
>> +	class_interface_unregister(&acpihp_drv_interface);
>> +}
>> +
>> +module_init(acpihp_drv_init);
>> +module_exit(acpihp_drv_exit);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("Jiang Liu <jiang.liu@huawei.com>");
>> +MODULE_AUTHOR("Hanjun Guo <guohanjun@huawei.com>");
> 


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Tang Chen - Aug. 9, 2012, 8:41 a.m.
Hi Liu ~

On 08/09/2012 03:40 PM, Jiang Liu wrote:
> Hi Tang,
> 	Thanks for testing.
> 	Currently there's a limitation that you need to insert acpihp_enum driver first.

Sorry, I didn't make it clear. I did load acpihp_enum module first, and then load acpihp_drv.

And I just tried it some more times. It just hung up, but dmesg had no output.
Like this:

# modprobe acpihp_enum
(OK, and sysfs interfaces have been created)
# modprobe acpihp_drv
(hang up)

# dmesg
(nothing)

The "modprobe acpihp_drv" process's call trace shows that it hung at the following function:
#0  0x00000032836aab80 in __nanosleep_nocancel () from /lib64/libc.so.6
#1  0x00000032836deb64 in usleep () from /lib64/libc.so.6
......

I have tried several times and I cannot reproduce the situation I just said.
Maybe my box has something different with yours. And I'll try to find out why.

Thanks for your advice. :)

> Will fix this issue in next version.
> 	Regards!
> 	Gerry
> 
> On 2012-8-9 15:12, Tang Chen wrote:
>> Hi Liu~
>>
>> I compiled this driver as a module, acpihp_drv. And when I loaded this module, it
>> gave the following error message:
>>
>> # modprobe acpihp_drv
>> (the command hangs up, no return after 10 min)
>>
>> #dmesg
>> ......
>> [  126.643350] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
>> [  126.644007] IP: [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>> [  126.644007] PGD 105277a067 PUD 104f823067 PMD 0 
>> [  126.644007] Oops: 0002 [#1] SMP 
>> [  126.644007] Modules linked in: acpihp_drv(+) ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle bridge stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel microcode lpc_ich mfd_core pcspkr i2c_i801 i2c_core ioatdma e1000e acpi_memhotplug i7core_edac edac_core igb dca mptsas mptscsih mptbase scsi_transport_sas
>> [  126.644007] CPU 10 
>> [  126.644007] Pid: 2821, comm: modprobe Tainted: G       A     3.6.0-rc1+ #6 FUJITSU-SV PRIMEQUEST 1800E/SB
>> [  126.644007] RIP: 0010:[<ffffffff814c0cd3>]  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>> [  126.644007] RSP: 0018:ffff8810589a9de8  EFLAGS: 00010246
>> [  126.644007] RAX: 0000000000000000 RBX: 0000000000000078 RCX: 0000000000000000
>> [  126.644007] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000078
>> [  126.644007] RBP: ffff8810589a9e08 R08: 0000000000000000 R09: ffff8810589a9d88
>> [  126.644007] R10: 00000000000013e5 R11: 00000000000013e5 R12: ffffffffa01460d0
>> [  126.644007] R13: 0000000000000000 R14: ffffffffa014732b R15: 00000000000000bf
>> [  126.644007] FS:  00007fecb1802700(0000) GS:ffff88105e640000(0000) knlGS:0000000000000000
>> [  126.644007] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [  126.644007] CR2: 0000000000000078 CR3: 0000001052772000 CR4: 00000000000007e0
>> [  126.644007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> [  126.644007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>> [  126.644007] Process modprobe (pid: 2821, threadinfo ffff8810589a8000, task ffff8810592f8000)
>> [  126.644007] Stack:
>> [  126.644007]  ffff8810589a9e08 ffffffff810be37f ffffffffa0146220 ffffffff81a7b390
>> [  126.644007]  ffff8810589a9e58 ffffffff81317eb3 ffff8810589a9e48 0000000000000000
>> [  126.644007]  ffffffff81a342c0 ffffffff81a342e0 0000000000000000 ffffffffa0146220
>> [  126.644007] Call Trace:
>> [  126.644007]  [<ffffffff810be37f>] ? tracepoint_module_notify+0xd9/0x14a
>> [  126.644007]  [<ffffffff81317eb3>] class_interface_register+0x4a/0xbc
>> [  126.644007]  [<ffffffffa00b8000>] ? 0xffffffffa00b7fff
>> [  126.644007]  [<ffffffffa00b8010>] acpihp_drv_init+0x10/0x12 [acpihp_drv]
>> [  126.644007]  [<ffffffff8100207f>] do_one_initcall+0x7f/0x139
>> [  126.644007]  [<ffffffff81093414>] sys_init_module+0x12d3/0x14e3
>> [  126.644007]  [<ffffffff81264b0d>] ? ddebug_dyndbg_boot_param_cb+0x45/0x45
>> [  126.644007]  [<ffffffff814c9469>] system_call_fastpath+0x16/0x1b
>> [  126.644007] Code: 48 8b 04 25 80 c6 00 00 48 89 43 18 31 c0 5b 5b c9 c3 55 48 89 e5 53 48 83 ec 18 66 66 66 66 90 48 89 fb e8 5a 0c 00 00 48 89 df <f0> ff 0f 79 05 e8 06 ff ff ff 65 48 8b 04 25 80 c6 00 00 48 89 
>> [  126.644007] RIP  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>> [  126.644007]  RSP <ffff8810589a9de8>
>> [  126.644007] CR2: 0000000000000078
>> [  129.981335] ---[ end trace da17e9c9de8dd560 ]---
>> [  139.085895] nr_pdflush_threads exported in /proc is scheduled for removal
>> [  139.167394] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case.  If you have one, please send an email to linux-mm@kvack.org.
>>
>> Looks like it dereferenced a NULL pointer here.
>> May be it was my mistake that I didn't configure the environment correctly.
>> Would you please give me some advice ?
>>
>> Thanks. :)
>>
>>
Jiang Liu - Aug. 9, 2012, 9:36 a.m.
On 2012-8-9 16:41, Tang Chen wrote:
> Hi Liu ~
> 
> On 08/09/2012 03:40 PM, Jiang Liu wrote:
>> Hi Tang,
>> 	Thanks for testing.
>> 	Currently there's a limitation that you need to insert acpihp_enum driver first.
> 
> Sorry, I didn't make it clear. I did load acpihp_enum module first, and then load acpihp_drv.
> 
> And I just tried it some more times. It just hung up, but dmesg had no output.
> Like this:
> 
> # modprobe acpihp_enum
> (OK, and sysfs interfaces have been created)
> # modprobe acpihp_drv
> (hang up)
> 
> # dmesg
> (nothing)
> 
> The "modprobe acpihp_drv" process's call trace shows that it hung at the following function:
> #0  0x00000032836aab80 in __nanosleep_nocancel () from /lib64/libc.so.6
> #1  0x00000032836deb64 in usleep () from /lib64/libc.so.6
> ......
> 
> I have tried several times and I cannot reproduce the situation I just said.
You can reproduce it by loading acpihp_drv without acpihp_enum driver, I guess.
The acpihp_drv module_init() should call acpihp_register_class() to initialize the core.

> Maybe my box has something different with yours. And I'll try to find out why.
> 
> Thanks for your advice. :)
> 
>> Will fix this issue in next version.
>> 	Regards!
>> 	Gerry
>>
>> On 2012-8-9 15:12, Tang Chen wrote:
>>> Hi Liu~
>>>
>>> I compiled this driver as a module, acpihp_drv. And when I loaded this module, it
>>> gave the following error message:
>>>
>>> # modprobe acpihp_drv
>>> (the command hangs up, no return after 10 min)
>>>
>>> #dmesg
>>> ......
>>> [  126.643350] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
>>> [  126.644007] IP: [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>>> [  126.644007] PGD 105277a067 PUD 104f823067 PMD 0 
>>> [  126.644007] Oops: 0002 [#1] SMP 
>>> [  126.644007] Modules linked in: acpihp_drv(+) ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle bridge stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel microcode lpc_ich mfd_core pcspkr i2c_i801 i2c_core ioatdma e1000e acpi_memhotplug i7core_edac edac_core igb dca mptsas mptscsih mptbase scsi_transport_sas
>>> [  126.644007] CPU 10 
>>> [  126.644007] Pid: 2821, comm: modprobe Tainted: G       A     3.6.0-rc1+ #6 FUJITSU-SV PRIMEQUEST 1800E/SB
>>> [  126.644007] RIP: 0010:[<ffffffff814c0cd3>]  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>>> [  126.644007] RSP: 0018:ffff8810589a9de8  EFLAGS: 00010246
>>> [  126.644007] RAX: 0000000000000000 RBX: 0000000000000078 RCX: 0000000000000000
>>> [  126.644007] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000078
>>> [  126.644007] RBP: ffff8810589a9e08 R08: 0000000000000000 R09: ffff8810589a9d88
>>> [  126.644007] R10: 00000000000013e5 R11: 00000000000013e5 R12: ffffffffa01460d0
>>> [  126.644007] R13: 0000000000000000 R14: ffffffffa014732b R15: 00000000000000bf
>>> [  126.644007] FS:  00007fecb1802700(0000) GS:ffff88105e640000(0000) knlGS:0000000000000000
>>> [  126.644007] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [  126.644007] CR2: 0000000000000078 CR3: 0000001052772000 CR4: 00000000000007e0
>>> [  126.644007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> [  126.644007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>>> [  126.644007] Process modprobe (pid: 2821, threadinfo ffff8810589a8000, task ffff8810592f8000)
>>> [  126.644007] Stack:
>>> [  126.644007]  ffff8810589a9e08 ffffffff810be37f ffffffffa0146220 ffffffff81a7b390
>>> [  126.644007]  ffff8810589a9e58 ffffffff81317eb3 ffff8810589a9e48 0000000000000000
>>> [  126.644007]  ffffffff81a342c0 ffffffff81a342e0 0000000000000000 ffffffffa0146220
>>> [  126.644007] Call Trace:
>>> [  126.644007]  [<ffffffff810be37f>] ? tracepoint_module_notify+0xd9/0x14a
>>> [  126.644007]  [<ffffffff81317eb3>] class_interface_register+0x4a/0xbc
>>> [  126.644007]  [<ffffffffa00b8000>] ? 0xffffffffa00b7fff
>>> [  126.644007]  [<ffffffffa00b8010>] acpihp_drv_init+0x10/0x12 [acpihp_drv]
>>> [  126.644007]  [<ffffffff8100207f>] do_one_initcall+0x7f/0x139
>>> [  126.644007]  [<ffffffff81093414>] sys_init_module+0x12d3/0x14e3
>>> [  126.644007]  [<ffffffff81264b0d>] ? ddebug_dyndbg_boot_param_cb+0x45/0x45
>>> [  126.644007]  [<ffffffff814c9469>] system_call_fastpath+0x16/0x1b
>>> [  126.644007] Code: 48 8b 04 25 80 c6 00 00 48 89 43 18 31 c0 5b 5b c9 c3 55 48 89 e5 53 48 83 ec 18 66 66 66 66 90 48 89 fb e8 5a 0c 00 00 48 89 df <f0> ff 0f 79 05 e8 06 ff ff ff 65 48 8b 04 25 80 c6 00 00 48 89 
>>> [  126.644007] RIP  [<ffffffff814c0cd3>] mutex_lock+0x19/0x37
>>> [  126.644007]  RSP <ffff8810589a9de8>
>>> [  126.644007] CR2: 0000000000000078
>>> [  129.981335] ---[ end trace da17e9c9de8dd560 ]---
>>> [  139.085895] nr_pdflush_threads exported in /proc is scheduled for removal
>>> [  139.167394] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case.  If you have one, please send an email to linux-mm@kvack.org.
>>>
>>> Looks like it dereferenced a NULL pointer here.
>>> May be it was my mistake that I didn't configure the environment correctly.
>>> Would you please give me some advice ?
>>>
>>> Thanks. :)
>>>
>>>
> 


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Tang Chen - Aug. 10, 2012, 4:39 a.m.
On 08/09/2012 05:36 PM, Jiang Liu wrote:
>> And I just tried it some more times. It just hung up, but dmesg had no output.
>> Like this:
>>
>> # modprobe acpihp_enum
>> (OK, and sysfs interfaces have been created)
>> # modprobe acpihp_drv
>> (hang up)
>>
>> # dmesg
>> (nothing)
>>
>> The "modprobe acpihp_drv" process's call trace shows that it hung at the following function:
>> #0  0x00000032836aab80 in __nanosleep_nocancel () from /lib64/libc.so.6
>> #1  0x00000032836deb64 in usleep () from /lib64/libc.so.6
>> ......
>>
>> I have tried several times and I cannot reproduce the situation I just said.
> You can reproduce it by loading acpihp_drv without acpihp_enum driver, I guess.
> The acpihp_drv module_init() should call acpihp_register_class() to initialize the core.
> 
Hi~

True. Thanks for your comments. :)
Since I'm new in PCI related area, if you don't mind, would you please give me some more advice about the following problem ?
Thanks. :)

"modprobe acpihp_drv" command failed, but acpihp_drv was loaded successfully, and always in use.
It cannot be removed. Is it a problem ?

[root@DP tangchen]# lsmod | grep acpi
acpi_cpufreq            9542  0 
freq_table              5030  2 cpufreq_ondemand,acpi_cpufreq
mperf                   1391  1 acpi_cpufreq
acpi_memhotplug         4414  0 

[root@DP tangchen]# modprobe acpihp_drv
Killed								(NOTE: The NULL pointer problem happened here.)

[root@DP tangchen]# echo $?
137

[root@DP tangchen]# lsmod | grep acpi
acpihp_drv             24925  1 				(NOTE: Here, the module is loaded.)
acpi_cpufreq            9542  0 
freq_table              5030  2 cpufreq_ondemand,acpi_cpufreq
mperf                   1391  1 acpi_cpufreq
acpi_memhotplug         4414  0 

[root@DP tangchen]# rmmod acpihp_drv
ERROR: Module acpihp_drv is in use


The core.c file has been compiled into kernel because of my configuration "CONFIG_ACPI_HOTPLUG=y".
As my colleague said, in this case, there is no dependency between acpihp_enum and acpihp_drv.
So I think, do we need to compile core.c into acpihp_enum module, or simply check if acpihp_enum 
has been loaded in acpihp_drv_init() ?
I am not sure if it is a good idea to move acpihp_slot_class definition and all related API to 
acpihp_enum module.

Thanks again for your comments and patient. :)

Patch

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index c9f7918..89047a3 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -354,6 +354,18 @@  config ACPI_HOTPLUG_ENUM_EJ0
 
 	  It's the default method to detect ACPI hotplug slots.
 
+config ACPI_HOTPLUG_DRIVER
+	tristate "ACPI Based System Device Hotplug Driver"
+	depends on ACPI_HOTPLUG
+	default y
+	help
+	  This driver enables ACPI based system device hotplug, including
+	  physical processor, memory device, IO host bridge and computer
+	  node etc.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called acpihp_drv.
+
 config ACPI_CONTAINER
 	tristate "Container and Module Devices (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
diff --git a/drivers/acpi/hotplug/Makefile b/drivers/acpi/hotplug/Makefile
index 25fac24..d69832f 100644
--- a/drivers/acpi/hotplug/Makefile
+++ b/drivers/acpi/hotplug/Makefile
@@ -8,3 +8,6 @@  acpihp-y					= core.o device.o
 obj-$(CONFIG_ACPI_HOTPLUG_ENUM)			+= acpihp_enum.o
 acpihp_enum-y					= slot_enum.o
 acpihp_enum-y					+= slot_enum_ej0.o
+
+obj-$(CONFIG_ACPI_HOTPLUG_DRIVER)		+= acpihp_drv.o
+acpihp_drv-y					= drv_main.o
diff --git a/drivers/acpi/hotplug/acpihp_drv.h b/drivers/acpi/hotplug/acpihp_drv.h
new file mode 100644
index 0000000..18330f7
--- /dev/null
+++ b/drivers/acpi/hotplug/acpihp_drv.h
@@ -0,0 +1,62 @@ 
+/*
+ * Copyright (C) 2011 Huawei Tech. Co., Ltd.
+ * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
+ * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef	__ACPIHP_DRV_H__
+#define	__ACPIHP_DRV_H__
+
+/* Commands to change state of a hotplug slot */
+enum acpihp_drv_cmd {
+	ACPIHP_DRV_CMD_NOOP = 0,
+	ACPIHP_DRV_CMD_POWERON = 0x1,
+	ACPIHP_DRV_CMD_CONNECT = 0x2,
+	ACPIHP_DRV_CMD_CONFIGURE = 0x4,
+	ACPIHP_DRV_CMD_UNCONFIGURE = 0x8,
+	ACPIHP_DRV_CMD_DISCONNECT = 0x10,
+	ACPIHP_DRV_CMD_POWEROFF = 0x20,
+	ACPIHP_DRV_CMD_CANCEL = 0x40,
+	ACPIHP_DRV_CMD_MAX
+};
+
+/* Hotplug operations may be triggered by firmware or OS */
+enum acpihp_dev_event {
+	ACPIHP_DRV_EVENT_FROM_FW,
+	ACPIHP_DRV_EVENT_FROM_OS
+};
+
+struct acpihp_slot_drv {
+	enum acpihp_dev_event	event_flag;
+	struct mutex		op_mutex; /* Prevent concurrent hotplugs. */
+	struct list_head	depend_list; /* Dependency relationship */
+	atomic_t		cancel_status;
+	atomic_t		cancel_flag;
+	struct acpihp_cancel_context	cancel_ctx;
+};
+
+void acpihp_drv_get_data(struct acpihp_slot *slot,
+			 struct acpihp_slot_drv **data);
+int acpihp_drv_enumerate_devices(struct acpihp_slot *slot);
+void acpihp_drv_update_slot_state(struct acpihp_slot *slot);
+int acpihp_drv_update_slot_status(struct acpihp_slot *slot);
+
+#endif	/* __ACPIHP_DRV_H__ */
diff --git a/drivers/acpi/hotplug/drv_main.c b/drivers/acpi/hotplug/drv_main.c
new file mode 100644
index 0000000..538772d
--- /dev/null
+++ b/drivers/acpi/hotplug/drv_main.c
@@ -0,0 +1,331 @@ 
+/*
+ * Copyright (C) 2011 Huawei Tech. Co., Ltd.
+ * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
+ * Copyright (C) 2011 Hanjun Guo <guohanjun@huawei.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_hotplug.h>
+#include "acpihp_drv.h"
+
+static struct class_interface acpihp_drv_interface;
+
+void acpihp_drv_get_data(struct acpihp_slot *slot,
+			 struct acpihp_slot_drv **data)
+{
+	*data = NULL;
+	acpihp_slot_get_drv_data(slot, &acpihp_drv_interface, (void **)data);
+}
+
+/* Update slot state according to state of devices connecting to it. */
+void acpihp_drv_update_slot_state(struct acpihp_slot *slot)
+{
+	enum acpihp_dev_type type;
+	enum acpihp_slot_state state;
+	struct klist_iter iter;
+	struct klist_node *ip;
+	struct acpihp_dev_node *dp;
+	bool connected = false;
+	bool configured = false;
+
+	if (!acpihp_slot_present(slot)) {
+		state = ACPIHP_SLOT_STATE_ABSENT;
+		goto out;
+	} else if (!acpihp_slot_powered(slot)) {
+		state = ACPIHP_SLOT_STATE_PRESENT;
+		goto out;
+	}
+
+	for (type = ACPIHP_DEV_TYPE_UNKNOWN;
+	     type < ACPIHP_DEV_TYPE_MAX && !configured;
+	     type++) {
+		klist_iter_init(&slot->dev_lists[type], &iter);
+		while ((ip = klist_next(&iter)) != NULL) {
+			connected = true;
+			dp = container_of(ip, struct acpihp_dev_node, node);
+			if (dp->state == DEVICE_STATE_CONFIGURED) {
+				configured = true;
+				break;
+			}
+		}
+		klist_iter_exit(&iter);
+	}
+
+	if (configured)
+		state = ACPIHP_SLOT_STATE_CONFIGURED;
+	else if (connected)
+		state = ACPIHP_SLOT_STATE_CONNECTED;
+	else
+		state = ACPIHP_SLOT_STATE_POWERED;
+
+out:
+	acpihp_slot_change_state(slot, state);
+}
+
+/* Update slot state according to status of devices connecting to it. */
+int acpihp_drv_update_slot_status(struct acpihp_slot *slot)
+{
+	int ret = 0;
+	enum acpihp_dev_type type;
+	struct klist_iter iter;
+	struct klist_node *ip;
+	struct acpihp_dev_node *np;
+	struct acpi_device *dev;
+	struct acpihp_dev_info *info;
+
+	if (!slot)
+		return -EINVAL;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	for (type = ACPIHP_DEV_TYPE_MEM; type <= ACPIHP_DEV_TYPE_HOST_BRIDGE;
+	     type++) {
+		klist_iter_init(&slot->dev_lists[type], &iter);
+		while ((ip = klist_next(&iter)) != NULL) {
+			np = container_of(ip, struct acpihp_dev_node, node);
+			dev = container_of(np->dev, struct acpi_device, dev);
+			ret = acpihp_dev_get_info(dev, info);
+			if (ret) {
+				ACPIHP_DEBUG("fails to get info about %s.\n",
+					     dev_name(&dev->dev));
+				goto out;
+			}
+
+			if (info->status & ACPIHP_DEV_STATUS_FAULT)
+				acpihp_slot_set_flag(slot,
+						ACPIHP_SLOT_FLAG_FAULT);
+			if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
+				acpihp_slot_set_flag(slot,
+						ACPIHP_SLOT_FLAG_IRREMOVABLE);
+		}
+	}
+
+out:
+	kfree(info);
+
+	return ret;
+}
+EXPORT_SYMBOL(acpihp_drv_update_slot_status);
+
+/* Add ACPI device to hotplug slot's device list */
+static acpi_status acpihp_drv_enum_device(struct acpi_device *dev, void *argp)
+{
+	int ret = -ENOMEM;
+	acpi_status rv = AE_OK;
+	enum acpihp_dev_type type;
+	enum acpihp_dev_state state;
+	struct acpihp_dev_info *info;
+	struct acpihp_slot *slot = (struct acpihp_slot *)argp;
+
+	if (acpihp_dev_get_type(dev->handle, &type)) {
+		ACPIHP_DEBUG("fails to get device type of %s.\n",
+			     dev_name(&dev->dev));
+		return AE_ERROR;
+	} else if (type == ACPIHP_DEV_TYPE_MAX) {
+		/*
+		 * Some ACPI objects for IO devices, such as PCI/IDE etc, only
+		 * implement _ADR instead of _HID/_CID, skip them.
+		 */
+		return AE_CTRL_DEPTH;
+	}
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (info)
+		ret = acpihp_dev_get_info(dev, info);
+
+	if (!ret) {
+		if (info->status & ACPIHP_DEV_STATUS_STARTED)
+			state = DEVICE_STATE_CONFIGURED;
+		else
+			state = DEVICE_STATE_CONNECTED;
+
+		if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
+			acpihp_slot_set_flag(slot,
+					     ACPIHP_SLOT_FLAG_IRREMOVABLE);
+		if (info->status & ACPIHP_DEV_STATUS_FAULT)
+			acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_FAULT);
+
+		if (acpihp_slot_add_device(slot, type, state, &dev->dev)) {
+			ACPIHP_DEBUG("fails to add %s to slot %s.\n",
+				     dev_name(&dev->dev), slot->name);
+			rv = AE_ERROR;
+		}
+	} else {
+		ACPIHP_DEBUG("fails to query device info of %s.\n",
+			     dev_name(&dev->dev));
+	}
+
+	kfree(info);
+
+	return rv;
+}
+
+/*
+ * Enumerator all devices connecting to a slot and add them onto slot's
+ * device lists.
+ */
+int acpihp_drv_enumerate_devices(struct acpihp_slot *slot)
+{
+	return acpihp_walk_devices(slot->handle, acpihp_drv_enum_device, slot);
+}
+
+static void acpihp_drv_remove_devices(struct acpihp_slot *slot)
+{
+	enum acpihp_dev_type type;
+
+	for (type = ACPIHP_DEV_TYPE_UNKNOWN; type < ACPIHP_DEV_TYPE_MAX; type++)
+		acpihp_remove_device_list(&slot->dev_lists[type]);
+}
+
+/* Callback function for ACPI system event notification. */
+static void acpihp_drv_event_handler(acpi_handle handle, u32 event,
+				     void *context)
+{
+	/* TODO: handle ACPI hotplug events */
+}
+
+static acpi_status acpihp_drv_install_handler(struct acpihp_slot *slot)
+{
+	acpi_status status;
+
+	status = acpi_install_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
+					     acpihp_drv_event_handler, slot);
+	ACPIHP_DEBUG("%s to install event handler for %s.\n",
+		     ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
+
+	return status;
+}
+
+static void acpihp_drv_uninstall_handler(struct acpihp_slot *slot)
+{
+	acpi_status status;
+
+	status = acpi_remove_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
+					    acpihp_drv_event_handler);
+	ACPIHP_DEBUG("%s to uninstall event handler for %s.\n",
+		ACPI_SUCCESS(status) ? "succeeds" : "fails", slot->name);
+}
+
+static int acpihp_drv_slot_add(struct device *dev, struct class_interface *intf)
+{
+	struct acpihp_slot_drv *drv_data;
+	struct acpihp_slot *slot = container_of(dev, struct acpihp_slot, dev);
+
+	/*
+	 * Try to hold a reference to the slot_ops structure to prevent
+	 * the platform specific enumerator driver from unloading.
+	 */
+	if (!slot->slot_ops || !try_module_get(slot->slot_ops->owner)) {
+		ACPIHP_DEBUG("fails to get reference to slot_ops for %s.\n",
+			     slot->name);
+		return -EINVAL;
+	}
+
+	/* install ACPI event notification handler for slot */
+	if (ACPI_FAILURE(acpihp_drv_install_handler(slot))) {
+		ACPIHP_DEBUG("fails to install event handler for %s.\n",
+			     slot->name);
+		module_put(slot->slot_ops->owner);
+		return -EBUSY;
+	}
+
+	/* Enumerate all devices if slot is already powered. */
+	if (!acpihp_slot_powered(slot))
+		ACPIHP_DEBUG("slot %s is powered off.\n", slot->name);
+	else if (acpihp_drv_enumerate_devices(slot))
+		acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_IRREMOVABLE);
+
+	acpihp_drv_update_slot_state(slot);
+
+	drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
+	if (drv_data) {
+		drv_data->event_flag = ACPIHP_DRV_EVENT_FROM_FW;
+		mutex_init(&drv_data->op_mutex);
+		INIT_LIST_HEAD(&drv_data->depend_list);
+	}
+	if (drv_data == NULL ||
+	    acpihp_slot_attach_drv_data(slot, intf, (void *)drv_data)) {
+		ACPIHP_DEBUG("fails to attach driver data for %s.\n",
+			     slot->name);
+		acpihp_drv_remove_devices(slot);
+		module_put(slot->slot_ops->owner);
+		kfree(drv_data);
+		return -ENOMEM;
+	}
+
+	ACPIHP_INFO("found hotplug slot %s.\n", slot->full_path);
+
+	return 0;
+}
+
+static void acpihp_drv_intf_remove(struct device *dev,
+				  struct class_interface *intf)
+{
+	struct acpihp_slot_drv *drv_data = NULL;
+	struct acpihp_slot *slot =
+			container_of(dev, struct acpihp_slot, dev);
+
+	ACPIHP_INFO("remove hotplug slot %s.\n", slot->full_path);
+
+	acpihp_drv_uninstall_handler(slot);
+	acpihp_drv_remove_devices(slot);
+	acpihp_slot_detach_drv_data(slot, intf, (void **)&drv_data);
+	if (drv_data != NULL)
+		kfree(drv_data);
+
+	module_put(slot->slot_ops->owner);
+}
+
+/*
+ * register a class driver onto the acpihp_slot_class to manage all system
+ * device hotplug slots.
+ */
+static struct class_interface acpihp_drv_interface = {
+	.class		= &acpihp_slot_class,
+	.add_dev	= acpihp_drv_slot_add,
+	.remove_dev	= acpihp_drv_intf_remove,
+};
+
+static int __init acpihp_drv_init(void)
+{
+	return class_interface_register(&acpihp_drv_interface);
+}
+
+static void __exit acpihp_drv_exit(void)
+{
+	class_interface_unregister(&acpihp_drv_interface);
+}
+
+module_init(acpihp_drv_init);
+module_exit(acpihp_drv_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiang Liu <jiang.liu@huawei.com>");
+MODULE_AUTHOR("Hanjun Guo <guohanjun@huawei.com>");