fs/sysfs/bin.c - kernel/mindspeed - Git at Google

 /*
  * fs/sysfs/bin.c - sysfs binary file implementation
  *
  * Copyright (c) 2003 Patrick Mochel
  * Copyright (c) 2003 Matthew Wilcox
  * Copyright (c) 2004 Silicon Graphics, Inc.
  * Copyright (c) 2007 SUSE Linux Products GmbH
  * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
  *
  * This file is released under the GPLv2.
  *
  * Please see Documentation/filesystems/sysfs.txt for more information.
  */

 #undef DEBUG

 #include <linux/errno.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/mm.h>

 #include <asm/uaccess.h>

 #include "sysfs.h"

 /*
  * There's one bin_buffer for each open file.
  *
  * filp->private_data points to bin_buffer and
  * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
  * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
  */
 static DEFINE_MUTEX(sysfs_bin_lock);

 struct bin_buffer {
 	struct mutex			mutex;
 	void				*buffer;
 	int				mmapped;
 	const struct vm_operations_struct *vm_ops;
 	struct file			*file;
 	struct hlist_node		list;
 };

 static int
 fill_read(struct file *file, char *buffer, loff_t off, size_t count)
 {
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 	int rc;

 	/* need attr_sd for attr, its parent for kobj */
 	if (!sysfs_get_active(attr_sd))
 		return -ENODEV;

 	rc = -EIO;
 	if (attr->read)
 		rc = attr->read(file, kobj, attr, buffer, off, count);

 	sysfs_put_active(attr_sd);

 	return rc;
 }

 static ssize_t
 read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
 {
 	struct bin_buffer *bb = file->private_data;
 	int size = file->f_path.dentry->d_inode->i_size;
 	loff_t offs = *off;
 	int count = min_t(size_t, bytes, PAGE_SIZE);
 	char *temp;

 	if (!bytes)
 		return 0;

 	if (size) {
 		if (offs > size)
 			return 0;
 		if (offs + count > size)
 			count = size - offs;
 	}

 	temp = kmalloc(count, GFP_KERNEL);
 	if (!temp)
 		return -ENOMEM;

 	mutex_lock(&bb->mutex);

 	count = fill_read(file, bb->buffer, offs, count);
 	if (count < 0) {
 		mutex_unlock(&bb->mutex);
 		goto out_free;
 	}

 	memcpy(temp, bb->buffer, count);

 	mutex_unlock(&bb->mutex);

 	if (copy_to_user(userbuf, temp, count)) {
 		count = -EFAULT;
 		goto out_free;
 	}

 	pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);

 	*off = offs + count;

  out_free:
 	kfree(temp);
 	return count;
 }

 static int
 flush_write(struct file *file, char *buffer, loff_t offset, size_t count)
 {
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 	int rc;

 	/* need attr_sd for attr, its parent for kobj */
 	if (!sysfs_get_active(attr_sd))
 		return -ENODEV;

 	rc = -EIO;
 	if (attr->write)
 		rc = attr->write(file, kobj, attr, buffer, offset, count);

 	sysfs_put_active(attr_sd);

 	return rc;
 }

 static ssize_t write(struct file *file, const char __user *userbuf,
 		     size_t bytes, loff_t *off)
 {
 	struct bin_buffer *bb = file->private_data;
 	int size = file->f_path.dentry->d_inode->i_size;
 	loff_t offs = *off;
 	int count = min_t(size_t, bytes, PAGE_SIZE);
 	char *temp;

 	if (!bytes)
 		return 0;

 	if (size) {
 		if (offs > size)
 			return 0;
 		if (offs + count > size)
 			count = size - offs;
 	}

 	temp = memdup_user(userbuf, count);
 	if (IS_ERR(temp))
 		return PTR_ERR(temp);

 	mutex_lock(&bb->mutex);

 	memcpy(bb->buffer, temp, count);

 	count = flush_write(file, bb->buffer, offs, count);
 	mutex_unlock(&bb->mutex);

 	if (count > 0)
 		*off = offs + count;

 	kfree(temp);
 	return count;
 }

 static void bin_vma_open(struct vm_area_struct *vma)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

 	if (!bb->vm_ops)
 		return;

 	if (!sysfs_get_active(attr_sd))
 		return;

 	if (bb->vm_ops->open)
 		bb->vm_ops->open(vma);

 	sysfs_put_active(attr_sd);
 }

 static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	int ret;

 	if (!bb->vm_ops)
 		return VM_FAULT_SIGBUS;

 	if (!sysfs_get_active(attr_sd))
 		return VM_FAULT_SIGBUS;

 	ret = VM_FAULT_SIGBUS;
 	if (bb->vm_ops->fault)
 		ret = bb->vm_ops->fault(vma, vmf);

 	sysfs_put_active(attr_sd);
 	return ret;
 }

 static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	int ret;

 	if (!bb->vm_ops)
 		return VM_FAULT_SIGBUS;

 	if (!sysfs_get_active(attr_sd))
 		return VM_FAULT_SIGBUS;

 	ret = 0;
 	if (bb->vm_ops->page_mkwrite)
 		ret = bb->vm_ops->page_mkwrite(vma, vmf);

 	sysfs_put_active(attr_sd);
 	return ret;
 }

 static int bin_access(struct vm_area_struct *vma, unsigned long addr,
 		  void *buf, int len, int write)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	int ret;

 	if (!bb->vm_ops)
 		return -EINVAL;

 	if (!sysfs_get_active(attr_sd))
 		return -EINVAL;

 	ret = -EINVAL;
 	if (bb->vm_ops->access)
 		ret = bb->vm_ops->access(vma, addr, buf, len, write);

 	sysfs_put_active(attr_sd);
 	return ret;
 }

 #ifdef CONFIG_NUMA
 static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	int ret;

 	if (!bb->vm_ops)
 		return 0;

 	if (!sysfs_get_active(attr_sd))
 		return -EINVAL;

 	ret = 0;
 	if (bb->vm_ops->set_policy)
 		ret = bb->vm_ops->set_policy(vma, new);

 	sysfs_put_active(attr_sd);
 	return ret;
 }

 static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
 					unsigned long addr)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct mempolicy *pol;

 	if (!bb->vm_ops)
 		return vma->vm_policy;

 	if (!sysfs_get_active(attr_sd))
 		return vma->vm_policy;

 	pol = vma->vm_policy;
 	if (bb->vm_ops->get_policy)
 		pol = bb->vm_ops->get_policy(vma, addr);

 	sysfs_put_active(attr_sd);
 	return pol;
 }

 static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
 			const nodemask_t *to, unsigned long flags)
 {
 	struct file *file = vma->vm_file;
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	int ret;

 	if (!bb->vm_ops)
 		return 0;

 	if (!sysfs_get_active(attr_sd))
 		return 0;

 	ret = 0;
 	if (bb->vm_ops->migrate)
 		ret = bb->vm_ops->migrate(vma, from, to, flags);

 	sysfs_put_active(attr_sd);
 	return ret;
 }
 #endif

 static const struct vm_operations_struct bin_vm_ops = {
 	.open		= bin_vma_open,
 	.fault		= bin_fault,
 	.page_mkwrite	= bin_page_mkwrite,
 	.access		= bin_access,
 #ifdef CONFIG_NUMA
 	.set_policy	= bin_set_policy,
 	.get_policy	= bin_get_policy,
 	.migrate	= bin_migrate,
 #endif
 };

 static int mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct bin_buffer *bb = file->private_data;
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 	int rc;

 	mutex_lock(&bb->mutex);

 	/* need attr_sd for attr, its parent for kobj */
 	rc = -ENODEV;
 	if (!sysfs_get_active(attr_sd))
 		goto out_unlock;

 	rc = -EINVAL;
 	if (!attr->mmap)
 		goto out_put;

 	rc = attr->mmap(file, kobj, attr, vma);
 	if (rc)
 		goto out_put;

 	/*
 	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
 	 * to satisfy versions of X which crash if the mmap fails: that
 	 * substitutes a new vm_file, and we don't then want bin_vm_ops.
 	 */
 	if (vma->vm_file != file)
 		goto out_put;

 	rc = -EINVAL;
 	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
 		goto out_put;

 	/*
 	 * It is not possible to successfully wrap close.
 	 * So error if someone is trying to use close.
 	 */
 	rc = -EINVAL;
 	if (vma->vm_ops && vma->vm_ops->close)
 		goto out_put;

 	rc = 0;
 	bb->mmapped = 1;
 	bb->vm_ops = vma->vm_ops;
 	vma->vm_ops = &bin_vm_ops;
 out_put:
 	sysfs_put_active(attr_sd);
 out_unlock:
 	mutex_unlock(&bb->mutex);

 	return rc;
 }

 static int open(struct inode * inode, struct file * file)
 {
 	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 	struct bin_buffer *bb = NULL;
 	int error;

 	/* binary file operations requires both @sd and its parent */
 	if (!sysfs_get_active(attr_sd))
 		return -ENODEV;

 	error = -EACCES;
 	if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
 		goto err_out;
 	if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
 		goto err_out;

 	error = -ENOMEM;
 	bb = kzalloc(sizeof(*bb), GFP_KERNEL);
 	if (!bb)
 		goto err_out;

 	bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!bb->buffer)
 		goto err_out;

 	mutex_init(&bb->mutex);
 	bb->file = file;
 	file->private_data = bb;

 	mutex_lock(&sysfs_bin_lock);
 	hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
 	mutex_unlock(&sysfs_bin_lock);

 	/* open succeeded, put active references */
 	sysfs_put_active(attr_sd);
 	return 0;

  err_out:
 	sysfs_put_active(attr_sd);
 	kfree(bb);
 	return error;
 }

 static int release(struct inode * inode, struct file * file)
 {
 	struct bin_buffer *bb = file->private_data;

 	mutex_lock(&sysfs_bin_lock);
 	hlist_del(&bb->list);
 	mutex_unlock(&sysfs_bin_lock);

 	kfree(bb->buffer);
 	kfree(bb);
 	return 0;
 }

 const struct file_operations bin_fops = {
 	.read		= read,
 	.write		= write,
 	.mmap		= mmap,
 	.llseek		= generic_file_llseek,
 	.open		= open,
 	.release	= release,
 };


 void unmap_bin_file(struct sysfs_dirent *attr_sd)
 {
 	struct bin_buffer *bb;
 	struct hlist_node *tmp;

 	if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
 		return;

 	mutex_lock(&sysfs_bin_lock);

 	hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
 		struct inode *inode = bb->file->f_path.dentry->d_inode;

 		unmap_mapping_range(inode->i_mapping, 0, 0, 1);
 	}

 	mutex_unlock(&sysfs_bin_lock);
 }

 /**
  *	sysfs_create_bin_file - create binary file for object.
  *	@kobj:	object.
  *	@attr:	attribute descriptor.
  */

 int sysfs_create_bin_file(struct kobject *kobj,
 			  const struct bin_attribute *attr)
 {
 	BUG_ON(!kobj || !kobj->sd || !attr);

 	return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
 }


 /**
  *	sysfs_remove_bin_file - remove binary file for object.
  *	@kobj:	object.
  *	@attr:	attribute descriptor.
  */

 void sysfs_remove_bin_file(struct kobject *kobj,
 			   const struct bin_attribute *attr)
 {
 	sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
 }

 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
	/*
	* fs/sysfs/bin.c - sysfs binary file implementation
	*
	* Copyright (c) 2003 Patrick Mochel
	* Copyright (c) 2003 Matthew Wilcox
	* Copyright (c) 2004 Silicon Graphics, Inc.
	* Copyright (c) 2007 SUSE Linux Products GmbH
	* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
	*
	* This file is released under the GPLv2.
	*
	* Please see Documentation/filesystems/sysfs.txt for more information.
	*/

	#undef DEBUG

	#include <linux/errno.h>
	#include <linux/fs.h>
	#include <linux/kernel.h>
	#include <linux/kobject.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/mutex.h>
	#include <linux/mm.h>

	#include <asm/uaccess.h>

	#include "sysfs.h"

	/*
	* There's one bin_buffer for each open file.
	*
	* filp->private_data points to bin_buffer and
	* sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
	* sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
	*/
	static DEFINE_MUTEX(sysfs_bin_lock);

	struct bin_buffer {
	struct mutex mutex;
	void *buffer;
	int mmapped;
	const struct vm_operations_struct *vm_ops;
	struct file *file;
	struct hlist_node list;
	};

	static int
	fill_read(struct file file, char buffer, loff_t off, size_t count)
	{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	/* need attr_sd for attr, its parent for kobj */
	if (!sysfs_get_active(attr_sd))
	return -ENODEV;

	rc = -EIO;
	if (attr->read)
	rc = attr->read(file, kobj, attr, buffer, off, count);

	sysfs_put_active(attr_sd);

	return rc;
	}

	static ssize_t
	read(struct file file, char __user userbuf, size_t bytes, loff_t *off)
	{
	struct bin_buffer *bb = file->private_data;
	int size = file->f_path.dentry->d_inode->i_size;
	loff_t offs = *off;
	int count = min_t(size_t, bytes, PAGE_SIZE);
	char *temp;

	if (!bytes)
	return 0;

	if (size) {
	if (offs > size)
	return 0;
	if (offs + count > size)
	count = size - offs;
	}

	temp = kmalloc(count, GFP_KERNEL);
	if (!temp)
	return -ENOMEM;

	mutex_lock(&bb->mutex);

	count = fill_read(file, bb->buffer, offs, count);
	if (count < 0) {
	mutex_unlock(&bb->mutex);
	goto out_free;
	}

	memcpy(temp, bb->buffer, count);

	mutex_unlock(&bb->mutex);

	if (copy_to_user(userbuf, temp, count)) {
	count = -EFAULT;
	goto out_free;
	}

	pr_debug("offs = %lld, off = %lld, count = %d\n", offs, off, count);

	*off = offs + count;

	out_free:
	kfree(temp);
	return count;
	}

	static int
	flush_write(struct file file, char buffer, loff_t offset, size_t count)
	{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	/* need attr_sd for attr, its parent for kobj */
	if (!sysfs_get_active(attr_sd))
	return -ENODEV;

	rc = -EIO;
	if (attr->write)
	rc = attr->write(file, kobj, attr, buffer, offset, count);

	sysfs_put_active(attr_sd);

	return rc;
	}

	static ssize_t write(struct file file, const char __user userbuf,
	size_t bytes, loff_t *off)
	{
	struct bin_buffer *bb = file->private_data;
	int size = file->f_path.dentry->d_inode->i_size;
	loff_t offs = *off;
	int count = min_t(size_t, bytes, PAGE_SIZE);
	char *temp;

	if (!bytes)
	return 0;

	if (size) {
	if (offs > size)
	return 0;
	if (offs + count > size)
	count = size - offs;
	}

	temp = memdup_user(userbuf, count);
	if (IS_ERR(temp))
	return PTR_ERR(temp);

	mutex_lock(&bb->mutex);

	memcpy(bb->buffer, temp, count);

	count = flush_write(file, bb->buffer, offs, count);
	mutex_unlock(&bb->mutex);

	if (count > 0)
	*off = offs + count;

	kfree(temp);
	return count;
	}

	static void bin_vma_open(struct vm_area_struct *vma)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

	if (!bb->vm_ops)
	return;

	if (!sysfs_get_active(attr_sd))
	return;

	if (bb->vm_ops->open)
	bb->vm_ops->open(vma);

	sysfs_put_active(attr_sd);
	}

	static int bin_fault(struct vm_area_struct vma, struct vm_fault vmf)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
	return VM_FAULT_SIGBUS;

	if (!sysfs_get_active(attr_sd))
	return VM_FAULT_SIGBUS;

	ret = VM_FAULT_SIGBUS;
	if (bb->vm_ops->fault)
	ret = bb->vm_ops->fault(vma, vmf);

	sysfs_put_active(attr_sd);
	return ret;
	}

	static int bin_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
	return VM_FAULT_SIGBUS;

	if (!sysfs_get_active(attr_sd))
	return VM_FAULT_SIGBUS;

	ret = 0;
	if (bb->vm_ops->page_mkwrite)
	ret = bb->vm_ops->page_mkwrite(vma, vmf);

	sysfs_put_active(attr_sd);
	return ret;
	}

	static int bin_access(struct vm_area_struct *vma, unsigned long addr,
	void *buf, int len, int write)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
	return -EINVAL;

	if (!sysfs_get_active(attr_sd))
	return -EINVAL;

	ret = -EINVAL;
	if (bb->vm_ops->access)
	ret = bb->vm_ops->access(vma, addr, buf, len, write);

	sysfs_put_active(attr_sd);
	return ret;
	}

	#ifdef CONFIG_NUMA
	static int bin_set_policy(struct vm_area_struct vma, struct mempolicy new)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
	return 0;

	if (!sysfs_get_active(attr_sd))
	return -EINVAL;

	ret = 0;
	if (bb->vm_ops->set_policy)
	ret = bb->vm_ops->set_policy(vma, new);

	sysfs_put_active(attr_sd);
	return ret;
	}

	static struct mempolicy bin_get_policy(struct vm_area_struct vma,
	unsigned long addr)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct mempolicy *pol;

	if (!bb->vm_ops)
	return vma->vm_policy;

	if (!sysfs_get_active(attr_sd))
	return vma->vm_policy;

	pol = vma->vm_policy;
	if (bb->vm_ops->get_policy)
	pol = bb->vm_ops->get_policy(vma, addr);

	sysfs_put_active(attr_sd);
	return pol;
	}

	static int bin_migrate(struct vm_area_struct vma, const nodemask_t from,
	const nodemask_t *to, unsigned long flags)
	{
	struct file *file = vma->vm_file;
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	int ret;

	if (!bb->vm_ops)
	return 0;

	if (!sysfs_get_active(attr_sd))
	return 0;

	ret = 0;
	if (bb->vm_ops->migrate)
	ret = bb->vm_ops->migrate(vma, from, to, flags);

	sysfs_put_active(attr_sd);
	return ret;
	}
	#endif

	static const struct vm_operations_struct bin_vm_ops = {
	.open = bin_vma_open,
	.fault = bin_fault,
	.page_mkwrite = bin_page_mkwrite,
	.access = bin_access,
	#ifdef CONFIG_NUMA
	.set_policy = bin_set_policy,
	.get_policy = bin_get_policy,
	.migrate = bin_migrate,
	#endif
	};

	static int mmap(struct file file, struct vm_area_struct vma)
	{
	struct bin_buffer *bb = file->private_data;
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
	int rc;

	mutex_lock(&bb->mutex);

	/* need attr_sd for attr, its parent for kobj */
	rc = -ENODEV;
	if (!sysfs_get_active(attr_sd))
	goto out_unlock;

	rc = -EINVAL;
	if (!attr->mmap)
	goto out_put;

	rc = attr->mmap(file, kobj, attr, vma);
	if (rc)
	goto out_put;

	/*
	* PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
	* to satisfy versions of X which crash if the mmap fails: that
	* substitutes a new vm_file, and we don't then want bin_vm_ops.
	*/
	if (vma->vm_file != file)
	goto out_put;

	rc = -EINVAL;
	if (bb->mmapped && bb->vm_ops != vma->vm_ops)
	goto out_put;

	/*
	* It is not possible to successfully wrap close.
	* So error if someone is trying to use close.
	*/
	rc = -EINVAL;
	if (vma->vm_ops && vma->vm_ops->close)
	goto out_put;

	rc = 0;
	bb->mmapped = 1;
	bb->vm_ops = vma->vm_ops;
	vma->vm_ops = &bin_vm_ops;
	out_put:
	sysfs_put_active(attr_sd);
	out_unlock:
	mutex_unlock(&bb->mutex);

	return rc;
	}

	static int open(struct inode * inode, struct file * file)
	{
	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
	struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
	struct bin_buffer *bb = NULL;
	int error;

	/* binary file operations requires both @sd and its parent */
	if (!sysfs_get_active(attr_sd))
	return -ENODEV;

	error = -EACCES;
	if ((file->f_mode & FMODE_WRITE) && !(attr->write \|\| attr->mmap))
	goto err_out;
	if ((file->f_mode & FMODE_READ) && !(attr->read \|\| attr->mmap))
	goto err_out;

	error = -ENOMEM;
	bb = kzalloc(sizeof(*bb), GFP_KERNEL);
	if (!bb)
	goto err_out;

	bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!bb->buffer)
	goto err_out;

	mutex_init(&bb->mutex);
	bb->file = file;
	file->private_data = bb;

	mutex_lock(&sysfs_bin_lock);
	hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
	mutex_unlock(&sysfs_bin_lock);

	/* open succeeded, put active references */
	sysfs_put_active(attr_sd);
	return 0;

	err_out:
	sysfs_put_active(attr_sd);
	kfree(bb);
	return error;
	}

	static int release(struct inode * inode, struct file * file)
	{
	struct bin_buffer *bb = file->private_data;

	mutex_lock(&sysfs_bin_lock);
	hlist_del(&bb->list);
	mutex_unlock(&sysfs_bin_lock);

	kfree(bb->buffer);
	kfree(bb);
	return 0;
	}

	const struct file_operations bin_fops = {
	.read = read,
	.write = write,
	.mmap = mmap,
	.llseek = generic_file_llseek,
	.open = open,
	.release = release,
	};


	void unmap_bin_file(struct sysfs_dirent *attr_sd)
	{
	struct bin_buffer *bb;
	struct hlist_node *tmp;

	if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
	return;

	mutex_lock(&sysfs_bin_lock);

	hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
	struct inode *inode = bb->file->f_path.dentry->d_inode;

	unmap_mapping_range(inode->i_mapping, 0, 0, 1);
	}

	mutex_unlock(&sysfs_bin_lock);
	}

	/**
	* sysfs_create_bin_file - create binary file for object.
	* @kobj: object.
	* @attr: attribute descriptor.
	*/

	int sysfs_create_bin_file(struct kobject *kobj,
	const struct bin_attribute *attr)
	{
	BUG_ON(!kobj \|\| !kobj->sd \|\| !attr);

	return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
	}


	/**
	* sysfs_remove_bin_file - remove binary file for object.
	* @kobj: object.
	* @attr: attribute descriptor.
	*/

	void sysfs_remove_bin_file(struct kobject *kobj,
	const struct bin_attribute *attr)
	{
	sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
	}

	EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
	EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);