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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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26c9e3988e
If device is removal is initiated by two threads as below, mdev core attempts to create a syfs remove file on stale device. During this flow, below [1] call trace is observed. cpu-0 cpu-1 ----- ----- mdev_unregister_device() device_for_each_child mdev_device_remove_cb mdev_device_remove user_syscall remove_store() mdev_device_remove() [..] unregister device(); /* not found in list or * active=false. */ sysfs_create_file() ..Call trace Now that mdev core follows correct device removal sequence of the linux bus model, remove shouldn't fail in normal cases. If it fails, there is no point of creating a stale file or checking for specific error status. kernel: WARNING: CPU: 2 PID: 9348 at fs/sysfs/file.c:327 sysfs_create_file_ns+0x7f/0x90 kernel: CPU: 2 PID: 9348 Comm: bash Kdump: loaded Not tainted 5.1.0-rc6-vdevbus+ #6 kernel: Hardware name: Supermicro SYS-6028U-TR4+/X10DRU-i+, BIOS 2.0b 08/09/2016 kernel: RIP: 0010:sysfs_create_file_ns+0x7f/0x90 kernel: Call Trace: kernel: remove_store+0xdc/0x100 [mdev] kernel: kernfs_fop_write+0x113/0x1a0 kernel: vfs_write+0xad/0x1b0 kernel: ksys_write+0x5a/0xe0 kernel: do_syscall_64+0x5a/0x210 kernel: entry_SYSCALL_64_after_hwframe+0x49/0xbe Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Parav Pandit <parav@mellanox.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
285 lines
6.3 KiB
C
285 lines
6.3 KiB
C
/*
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* File attributes for Mediated devices
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*
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* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
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* Author: Neo Jia <cjia@nvidia.com>
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* Kirti Wankhede <kwankhede@nvidia.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/sysfs.h>
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#include <linux/ctype.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/uuid.h>
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#include <linux/mdev.h>
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#include "mdev_private.h"
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/* Static functions */
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static ssize_t mdev_type_attr_show(struct kobject *kobj,
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struct attribute *__attr, char *buf)
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{
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struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
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struct mdev_type *type = to_mdev_type(kobj);
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ssize_t ret = -EIO;
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if (attr->show)
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ret = attr->show(kobj, type->parent->dev, buf);
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return ret;
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}
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static ssize_t mdev_type_attr_store(struct kobject *kobj,
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struct attribute *__attr,
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const char *buf, size_t count)
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{
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struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
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struct mdev_type *type = to_mdev_type(kobj);
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ssize_t ret = -EIO;
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if (attr->store)
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ret = attr->store(&type->kobj, type->parent->dev, buf, count);
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return ret;
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}
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static const struct sysfs_ops mdev_type_sysfs_ops = {
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.show = mdev_type_attr_show,
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.store = mdev_type_attr_store,
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};
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static ssize_t create_store(struct kobject *kobj, struct device *dev,
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const char *buf, size_t count)
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{
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char *str;
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guid_t uuid;
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int ret;
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if ((count < UUID_STRING_LEN) || (count > UUID_STRING_LEN + 1))
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return -EINVAL;
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str = kstrndup(buf, count, GFP_KERNEL);
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if (!str)
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return -ENOMEM;
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ret = guid_parse(str, &uuid);
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kfree(str);
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if (ret)
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return ret;
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ret = mdev_device_create(kobj, dev, &uuid);
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if (ret)
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return ret;
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return count;
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}
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MDEV_TYPE_ATTR_WO(create);
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static void mdev_type_release(struct kobject *kobj)
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{
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struct mdev_type *type = to_mdev_type(kobj);
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pr_debug("Releasing group %s\n", kobj->name);
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kfree(type);
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}
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static struct kobj_type mdev_type_ktype = {
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.sysfs_ops = &mdev_type_sysfs_ops,
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.release = mdev_type_release,
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};
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static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
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struct attribute_group *group)
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{
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struct mdev_type *type;
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int ret;
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if (!group->name) {
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pr_err("%s: Type name empty!\n", __func__);
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return ERR_PTR(-EINVAL);
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}
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type = kzalloc(sizeof(*type), GFP_KERNEL);
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if (!type)
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return ERR_PTR(-ENOMEM);
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type->kobj.kset = parent->mdev_types_kset;
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ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
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"%s-%s", dev_driver_string(parent->dev),
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group->name);
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if (ret) {
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kfree(type);
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return ERR_PTR(ret);
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}
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ret = sysfs_create_file(&type->kobj, &mdev_type_attr_create.attr);
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if (ret)
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goto attr_create_failed;
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type->devices_kobj = kobject_create_and_add("devices", &type->kobj);
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if (!type->devices_kobj) {
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ret = -ENOMEM;
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goto attr_devices_failed;
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}
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ret = sysfs_create_files(&type->kobj,
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(const struct attribute **)group->attrs);
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if (ret) {
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ret = -ENOMEM;
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goto attrs_failed;
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}
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type->group = group;
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type->parent = parent;
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return type;
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attrs_failed:
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kobject_put(type->devices_kobj);
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attr_devices_failed:
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sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
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attr_create_failed:
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kobject_del(&type->kobj);
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kobject_put(&type->kobj);
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return ERR_PTR(ret);
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}
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static void remove_mdev_supported_type(struct mdev_type *type)
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{
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sysfs_remove_files(&type->kobj,
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(const struct attribute **)type->group->attrs);
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kobject_put(type->devices_kobj);
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sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
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kobject_del(&type->kobj);
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kobject_put(&type->kobj);
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}
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static int add_mdev_supported_type_groups(struct mdev_parent *parent)
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{
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int i;
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for (i = 0; parent->ops->supported_type_groups[i]; i++) {
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struct mdev_type *type;
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type = add_mdev_supported_type(parent,
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parent->ops->supported_type_groups[i]);
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if (IS_ERR(type)) {
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struct mdev_type *ltype, *tmp;
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list_for_each_entry_safe(ltype, tmp, &parent->type_list,
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next) {
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list_del(<ype->next);
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remove_mdev_supported_type(ltype);
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}
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return PTR_ERR(type);
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}
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list_add(&type->next, &parent->type_list);
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}
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return 0;
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}
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/* mdev sysfs functions */
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void parent_remove_sysfs_files(struct mdev_parent *parent)
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{
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struct mdev_type *type, *tmp;
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list_for_each_entry_safe(type, tmp, &parent->type_list, next) {
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list_del(&type->next);
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remove_mdev_supported_type(type);
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}
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sysfs_remove_groups(&parent->dev->kobj, parent->ops->dev_attr_groups);
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kset_unregister(parent->mdev_types_kset);
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}
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int parent_create_sysfs_files(struct mdev_parent *parent)
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{
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int ret;
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parent->mdev_types_kset = kset_create_and_add("mdev_supported_types",
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NULL, &parent->dev->kobj);
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if (!parent->mdev_types_kset)
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return -ENOMEM;
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INIT_LIST_HEAD(&parent->type_list);
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ret = sysfs_create_groups(&parent->dev->kobj,
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parent->ops->dev_attr_groups);
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if (ret)
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goto create_err;
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ret = add_mdev_supported_type_groups(parent);
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if (ret)
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sysfs_remove_groups(&parent->dev->kobj,
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parent->ops->dev_attr_groups);
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else
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return ret;
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create_err:
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kset_unregister(parent->mdev_types_kset);
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return ret;
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}
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static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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unsigned long val;
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if (kstrtoul(buf, 0, &val) < 0)
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return -EINVAL;
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if (val && device_remove_file_self(dev, attr)) {
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int ret;
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ret = mdev_device_remove(dev);
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if (ret)
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return ret;
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}
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return count;
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}
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static DEVICE_ATTR_WO(remove);
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static const struct attribute *mdev_device_attrs[] = {
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&dev_attr_remove.attr,
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NULL,
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};
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int mdev_create_sysfs_files(struct device *dev, struct mdev_type *type)
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{
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int ret;
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ret = sysfs_create_link(type->devices_kobj, &dev->kobj, dev_name(dev));
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if (ret)
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return ret;
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ret = sysfs_create_link(&dev->kobj, &type->kobj, "mdev_type");
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if (ret)
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goto type_link_failed;
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ret = sysfs_create_files(&dev->kobj, mdev_device_attrs);
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if (ret)
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goto create_files_failed;
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return ret;
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create_files_failed:
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sysfs_remove_link(&dev->kobj, "mdev_type");
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type_link_failed:
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sysfs_remove_link(type->devices_kobj, dev_name(dev));
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return ret;
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}
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void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type)
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{
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sysfs_remove_files(&dev->kobj, mdev_device_attrs);
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sysfs_remove_link(&dev->kobj, "mdev_type");
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sysfs_remove_link(type->devices_kobj, dev_name(dev));
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}
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