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![Eric W. Biederman](/assets/img/avatar_default.png)
bb->vm_ops is a cached copy of the vm_ops of the underlying sysfs bin file, which means that after sysfs_bin_remove_file completes it is only longer valid to deference bb->vm_ops. So move all of the tests of bb->vm_ops inside of where we hold the sysfs active lock. Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
506 lines
11 KiB
C
506 lines
11 KiB
C
/*
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* fs/sysfs/bin.c - sysfs binary file implementation
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Matthew Wilcox
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* Copyright (c) 2004 Silicon Graphics, Inc.
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#undef DEBUG
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/mm.h>
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#include <asm/uaccess.h>
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#include "sysfs.h"
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/*
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* There's one bin_buffer for each open file.
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*
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* filp->private_data points to bin_buffer and
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* sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
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* sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
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*/
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static DEFINE_MUTEX(sysfs_bin_lock);
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struct bin_buffer {
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struct mutex mutex;
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void *buffer;
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int mmapped;
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const struct vm_operations_struct *vm_ops;
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struct file *file;
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struct hlist_node list;
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};
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static int
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fill_read(struct file *file, char *buffer, loff_t off, size_t count)
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{
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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int rc;
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/* need attr_sd for attr, its parent for kobj */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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rc = -EIO;
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if (attr->read)
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rc = attr->read(file, kobj, attr, buffer, off, count);
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sysfs_put_active(attr_sd);
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return rc;
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}
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static ssize_t
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read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
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{
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struct bin_buffer *bb = file->private_data;
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int size = file->f_path.dentry->d_inode->i_size;
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loff_t offs = *off;
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int count = min_t(size_t, bytes, PAGE_SIZE);
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char *temp;
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if (!bytes)
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return 0;
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if (size) {
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if (offs > size)
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return 0;
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if (offs + count > size)
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count = size - offs;
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}
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temp = kmalloc(count, GFP_KERNEL);
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if (!temp)
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return -ENOMEM;
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mutex_lock(&bb->mutex);
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count = fill_read(file, bb->buffer, offs, count);
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if (count < 0) {
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mutex_unlock(&bb->mutex);
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goto out_free;
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}
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memcpy(temp, bb->buffer, count);
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mutex_unlock(&bb->mutex);
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if (copy_to_user(userbuf, temp, count)) {
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count = -EFAULT;
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goto out_free;
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}
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pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
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*off = offs + count;
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out_free:
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kfree(temp);
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return count;
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}
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static int
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flush_write(struct file *file, char *buffer, loff_t offset, size_t count)
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{
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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int rc;
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/* need attr_sd for attr, its parent for kobj */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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rc = -EIO;
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if (attr->write)
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rc = attr->write(file, kobj, attr, buffer, offset, count);
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sysfs_put_active(attr_sd);
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return rc;
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}
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static ssize_t write(struct file *file, const char __user *userbuf,
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size_t bytes, loff_t *off)
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{
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struct bin_buffer *bb = file->private_data;
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int size = file->f_path.dentry->d_inode->i_size;
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loff_t offs = *off;
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int count = min_t(size_t, bytes, PAGE_SIZE);
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char *temp;
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if (!bytes)
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return 0;
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if (size) {
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if (offs > size)
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return 0;
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if (offs + count > size)
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count = size - offs;
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}
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temp = memdup_user(userbuf, count);
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if (IS_ERR(temp))
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return PTR_ERR(temp);
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mutex_lock(&bb->mutex);
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memcpy(bb->buffer, temp, count);
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count = flush_write(file, bb->buffer, offs, count);
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mutex_unlock(&bb->mutex);
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if (count > 0)
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*off = offs + count;
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kfree(temp);
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return count;
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}
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static void bin_vma_open(struct vm_area_struct *vma)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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if (!bb->vm_ops)
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return;
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if (!sysfs_get_active(attr_sd))
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return;
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if (bb->vm_ops->open)
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bb->vm_ops->open(vma);
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sysfs_put_active(attr_sd);
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}
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static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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int ret;
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if (!bb->vm_ops)
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return VM_FAULT_SIGBUS;
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if (!sysfs_get_active(attr_sd))
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return VM_FAULT_SIGBUS;
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ret = VM_FAULT_SIGBUS;
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if (bb->vm_ops->fault)
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ret = bb->vm_ops->fault(vma, vmf);
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sysfs_put_active(attr_sd);
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return ret;
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}
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static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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int ret;
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if (!bb->vm_ops)
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return VM_FAULT_SIGBUS;
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if (!sysfs_get_active(attr_sd))
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return VM_FAULT_SIGBUS;
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ret = 0;
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if (bb->vm_ops->page_mkwrite)
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ret = bb->vm_ops->page_mkwrite(vma, vmf);
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sysfs_put_active(attr_sd);
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return ret;
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}
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static int bin_access(struct vm_area_struct *vma, unsigned long addr,
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void *buf, int len, int write)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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int ret;
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if (!bb->vm_ops)
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return -EINVAL;
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if (!sysfs_get_active(attr_sd))
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return -EINVAL;
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ret = -EINVAL;
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if (bb->vm_ops->access)
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ret = bb->vm_ops->access(vma, addr, buf, len, write);
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sysfs_put_active(attr_sd);
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return ret;
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}
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#ifdef CONFIG_NUMA
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static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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int ret;
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if (!bb->vm_ops)
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return 0;
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if (!sysfs_get_active(attr_sd))
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return -EINVAL;
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ret = 0;
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if (bb->vm_ops->set_policy)
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ret = bb->vm_ops->set_policy(vma, new);
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sysfs_put_active(attr_sd);
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return ret;
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}
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static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
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unsigned long addr)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct mempolicy *pol;
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if (!bb->vm_ops)
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return vma->vm_policy;
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if (!sysfs_get_active(attr_sd))
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return vma->vm_policy;
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pol = vma->vm_policy;
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if (bb->vm_ops->get_policy)
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pol = bb->vm_ops->get_policy(vma, addr);
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sysfs_put_active(attr_sd);
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return pol;
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}
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static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
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const nodemask_t *to, unsigned long flags)
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{
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struct file *file = vma->vm_file;
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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int ret;
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if (!bb->vm_ops)
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return 0;
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if (!sysfs_get_active(attr_sd))
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return 0;
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ret = 0;
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if (bb->vm_ops->migrate)
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ret = bb->vm_ops->migrate(vma, from, to, flags);
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sysfs_put_active(attr_sd);
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return ret;
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}
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#endif
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static const struct vm_operations_struct bin_vm_ops = {
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.open = bin_vma_open,
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.fault = bin_fault,
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.page_mkwrite = bin_page_mkwrite,
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.access = bin_access,
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#ifdef CONFIG_NUMA
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.set_policy = bin_set_policy,
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.get_policy = bin_get_policy,
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.migrate = bin_migrate,
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#endif
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};
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static int mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct bin_buffer *bb = file->private_data;
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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int rc;
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mutex_lock(&bb->mutex);
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/* need attr_sd for attr, its parent for kobj */
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rc = -ENODEV;
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if (!sysfs_get_active(attr_sd))
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goto out_unlock;
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rc = -EINVAL;
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if (!attr->mmap)
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goto out_put;
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rc = attr->mmap(file, kobj, attr, vma);
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if (rc)
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goto out_put;
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/*
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* PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
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* to satisfy versions of X which crash if the mmap fails: that
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* substitutes a new vm_file, and we don't then want bin_vm_ops.
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*/
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if (vma->vm_file != file)
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goto out_put;
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rc = -EINVAL;
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if (bb->mmapped && bb->vm_ops != vma->vm_ops)
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goto out_put;
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/*
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* It is not possible to successfully wrap close.
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* So error if someone is trying to use close.
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*/
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rc = -EINVAL;
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if (vma->vm_ops && vma->vm_ops->close)
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goto out_put;
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rc = 0;
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bb->mmapped = 1;
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bb->vm_ops = vma->vm_ops;
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vma->vm_ops = &bin_vm_ops;
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out_put:
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sysfs_put_active(attr_sd);
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out_unlock:
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mutex_unlock(&bb->mutex);
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return rc;
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}
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static int open(struct inode * inode, struct file * file)
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{
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
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struct bin_buffer *bb = NULL;
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int error;
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/* binary file operations requires both @sd and its parent */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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error = -EACCES;
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if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
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goto err_out;
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if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
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goto err_out;
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error = -ENOMEM;
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bb = kzalloc(sizeof(*bb), GFP_KERNEL);
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if (!bb)
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goto err_out;
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bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!bb->buffer)
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goto err_out;
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mutex_init(&bb->mutex);
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bb->file = file;
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file->private_data = bb;
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mutex_lock(&sysfs_bin_lock);
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hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
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mutex_unlock(&sysfs_bin_lock);
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/* open succeeded, put active references */
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sysfs_put_active(attr_sd);
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return 0;
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err_out:
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sysfs_put_active(attr_sd);
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kfree(bb);
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return error;
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}
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static int release(struct inode * inode, struct file * file)
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{
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struct bin_buffer *bb = file->private_data;
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mutex_lock(&sysfs_bin_lock);
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hlist_del(&bb->list);
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mutex_unlock(&sysfs_bin_lock);
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kfree(bb->buffer);
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kfree(bb);
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return 0;
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}
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const struct file_operations bin_fops = {
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.read = read,
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.write = write,
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.mmap = mmap,
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.llseek = generic_file_llseek,
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.open = open,
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.release = release,
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};
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void unmap_bin_file(struct sysfs_dirent *attr_sd)
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{
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struct bin_buffer *bb;
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struct hlist_node *tmp;
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if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
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return;
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mutex_lock(&sysfs_bin_lock);
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hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
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struct inode *inode = bb->file->f_path.dentry->d_inode;
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unmap_mapping_range(inode->i_mapping, 0, 0, 1);
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}
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mutex_unlock(&sysfs_bin_lock);
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}
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/**
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* sysfs_create_bin_file - create binary file for object.
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* @kobj: object.
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* @attr: attribute descriptor.
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*/
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int sysfs_create_bin_file(struct kobject *kobj,
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const struct bin_attribute *attr)
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{
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BUG_ON(!kobj || !kobj->sd || !attr);
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return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
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}
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/**
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* sysfs_remove_bin_file - remove binary file for object.
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* @kobj: object.
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* @attr: attribute descriptor.
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*/
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void sysfs_remove_bin_file(struct kobject *kobj,
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const struct bin_attribute *attr)
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{
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sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
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}
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EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
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EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
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