Re: [RFC PATCH v2 10/16] ACPIHP: system device hotplug driver skeleton

From: Jiang Liu
Date: Thu Aug 09 2012 - 03:42:39 EST

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@xxxxxxxxxx
>
> 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@xxxxxxxxxx>
>>
>> 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@xxxxxxxxx>
>> Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx>
>> ---
>> 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@xxxxxxxxxx>
>> + * Copyright (C) 2011 Hanjun Guo <guohanjun@xxxxxxxxxx>
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + *
>> + * 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@xxxxxxxxxx>
>> + * Copyright (C) 2011 Hanjun Guo <guohanjun@xxxxxxxxxx>
>> + *
>> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> + *
>> + * 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@xxxxxxxxxx>");
>> +MODULE_AUTHOR("Hanjun Guo <guohanjun@xxxxxxxxxx>");
>


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