fs/proc/inode.c - kernel/msm-4.9 - Gitiles

 /*
  *  linux/fs/proc/inode.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */

 #include <linux/time.h>
 #include <linux/proc_fs.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/stat.h>
 #include <linux/completion.h>
 #include <linux/poll.h>
 #include <linux/file.h>
 #include <linux/limits.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>

 #include <asm/system.h>
 #include <asm/uaccess.h>

 #include "internal.h"

 struct proc_dir_entry *de_get(struct proc_dir_entry *de)
 {
 	if (de)
 		atomic_inc(&de->count);
 	return de;
 }

 /*
  * Decrements the use count and checks for deferred deletion.
  */
 void de_put(struct proc_dir_entry *de)
 {
 	if (de) {
 		lock_kernel();
 		if (!atomic_read(&de->count)) {
 			printk("de_put: entry %s already free!\n", de->name);
 			unlock_kernel();
 			return;
 		}

 		if (atomic_dec_and_test(&de->count)) {
 			if (de->deleted) {
 				printk("de_put: deferred delete of %s\n",
 					de->name);
 				free_proc_entry(de);
 			}
 		}
 		unlock_kernel();
 	}
 }

 /*
  * Decrement the use count of the proc_dir_entry.
  */
 static void proc_delete_inode(struct inode *inode)
 {
 	struct proc_dir_entry *de;

 	truncate_inode_pages(&inode->i_data, 0);

 	/* Stop tracking associated processes */
 	put_pid(PROC_I(inode)->pid);

 	/* Let go of any associated proc directory entry */
 	de = PROC_I(inode)->pde;
 	if (de) {
 		if (de->owner)
 			module_put(de->owner);
 		de_put(de);
 	}
 	clear_inode(inode);
 }

 struct vfsmount *proc_mnt;

 static void proc_read_inode(struct inode * inode)
 {
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 }

 static struct kmem_cache * proc_inode_cachep;

 static struct inode *proc_alloc_inode(struct super_block *sb)
 {
 	struct proc_inode *ei;
 	struct inode *inode;

 	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
 	if (!ei)
 		return NULL;
 	ei->pid = NULL;
 	ei->fd = 0;
 	ei->op.proc_get_link = NULL;
 	ei->pde = NULL;
 	inode = &ei->vfs_inode;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 	return inode;
 }

 static void proc_destroy_inode(struct inode *inode)
 {
 	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
 }

 static void init_once(struct kmem_cache * cachep, void *foo)
 {
 	struct proc_inode *ei = (struct proc_inode *) foo;

 	inode_init_once(&ei->vfs_inode);
 }

 int __init proc_init_inodecache(void)
 {
 	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
 					     sizeof(struct proc_inode),
 					     0, (SLAB_RECLAIM_ACCOUNT|
 						SLAB_MEM_SPREAD|SLAB_PANIC),
 					     init_once);
 	return 0;
 }

 static int proc_remount(struct super_block *sb, int *flags, char *data)
 {
 	*flags |= MS_NODIRATIME;
 	return 0;
 }

 static const struct super_operations proc_sops = {
 	.alloc_inode	= proc_alloc_inode,
 	.destroy_inode	= proc_destroy_inode,
 	.read_inode	= proc_read_inode,
 	.drop_inode	= generic_delete_inode,
 	.delete_inode	= proc_delete_inode,
 	.statfs		= simple_statfs,
 	.remount_fs	= proc_remount,
 };

 static void pde_users_dec(struct proc_dir_entry *pde)
 {
 	spin_lock(&pde->pde_unload_lock);
 	pde->pde_users--;
 	if (pde->pde_unload_completion && pde->pde_users == 0)
 		complete(pde->pde_unload_completion);
 	spin_unlock(&pde->pde_unload_lock);
 }

 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	loff_t rv = -EINVAL;
 	loff_t (*llseek)(struct file *, loff_t, int);

 	spin_lock(&pde->pde_unload_lock);
 	/*
 	 * remove_proc_entry() is going to delete PDE (as part of module
 	 * cleanup sequence). No new callers into module allowed.
 	 */
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	/*
 	 * Bump refcount so that remove_proc_entry will wail for ->llseek to
 	 * complete.
 	 */
 	pde->pde_users++;
 	/*
 	 * Save function pointer under lock, to protect against ->proc_fops
 	 * NULL'ifying right after ->pde_unload_lock is dropped.
 	 */
 	llseek = pde->proc_fops->llseek;
 	spin_unlock(&pde->pde_unload_lock);

 	if (!llseek)
 		llseek = default_llseek;
 	rv = llseek(file, offset, whence);

 	pde_users_dec(pde);
 	return rv;
 }

 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	ssize_t rv = -EIO;
 	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	read = pde->proc_fops->read;
 	spin_unlock(&pde->pde_unload_lock);

 	if (read)
 		rv = read(file, buf, count, ppos);

 	pde_users_dec(pde);
 	return rv;
 }

 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	ssize_t rv = -EIO;
 	ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	write = pde->proc_fops->write;
 	spin_unlock(&pde->pde_unload_lock);

 	if (write)
 		rv = write(file, buf, count, ppos);

 	pde_users_dec(pde);
 	return rv;
 }

 static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	unsigned int rv = DEFAULT_POLLMASK;
 	unsigned int (*poll)(struct file *, struct poll_table_struct *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	poll = pde->proc_fops->poll;
 	spin_unlock(&pde->pde_unload_lock);

 	if (poll)
 		rv = poll(file, pts);

 	pde_users_dec(pde);
 	return rv;
 }

 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	long rv = -ENOTTY;
 	long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long);
 	int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
 	ioctl = pde->proc_fops->ioctl;
 	spin_unlock(&pde->pde_unload_lock);

 	if (unlocked_ioctl) {
 		rv = unlocked_ioctl(file, cmd, arg);
 		if (rv == -ENOIOCTLCMD)
 			rv = -EINVAL;
 	} else if (ioctl) {
 		lock_kernel();
 		rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
 		unlock_kernel();
 	}

 	pde_users_dec(pde);
 	return rv;
 }

 #ifdef CONFIG_COMPAT
 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	long rv = -ENOTTY;
 	long (*compat_ioctl)(struct file *, unsigned int, unsigned long);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	compat_ioctl = pde->proc_fops->compat_ioctl;
 	spin_unlock(&pde->pde_unload_lock);

 	if (compat_ioctl)
 		rv = compat_ioctl(file, cmd, arg);

 	pde_users_dec(pde);
 	return rv;
 }
 #endif

 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 	int rv = -EIO;
 	int (*mmap)(struct file *, struct vm_area_struct *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	mmap = pde->proc_fops->mmap;
 	spin_unlock(&pde->pde_unload_lock);

 	if (mmap)
 		rv = mmap(file, vma);

 	pde_users_dec(pde);
 	return rv;
 }

 static int proc_reg_open(struct inode *inode, struct file *file)
 {
 	struct proc_dir_entry *pde = PDE(inode);
 	int rv = 0;
 	int (*open)(struct inode *, struct file *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	open = pde->proc_fops->open;
 	spin_unlock(&pde->pde_unload_lock);

 	if (open)
 		rv = open(inode, file);

 	pde_users_dec(pde);
 	return rv;
 }

 static int proc_reg_release(struct inode *inode, struct file *file)
 {
 	struct proc_dir_entry *pde = PDE(inode);
 	int rv = 0;
 	int (*release)(struct inode *, struct file *);

 	spin_lock(&pde->pde_unload_lock);
 	if (!pde->proc_fops) {
 		spin_unlock(&pde->pde_unload_lock);
 		return rv;
 	}
 	pde->pde_users++;
 	release = pde->proc_fops->release;
 	spin_unlock(&pde->pde_unload_lock);

 	if (release)
 		rv = release(inode, file);

 	pde_users_dec(pde);
 	return rv;
 }

 static const struct file_operations proc_reg_file_ops = {
 	.llseek		= proc_reg_llseek,
 	.read		= proc_reg_read,
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= proc_reg_compat_ioctl,
 #endif
 	.mmap		= proc_reg_mmap,
 	.open		= proc_reg_open,
 	.release	= proc_reg_release,
 };

 #ifdef CONFIG_COMPAT
 static const struct file_operations proc_reg_file_ops_no_compat = {
 	.llseek		= proc_reg_llseek,
 	.read		= proc_reg_read,
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 	.mmap		= proc_reg_mmap,
 	.open		= proc_reg_open,
 	.release	= proc_reg_release,
 };
 #endif

 struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 				struct proc_dir_entry *de)
 {
 	struct inode * inode;

 	if (de != NULL && !try_module_get(de->owner))
 		goto out_mod;

 	inode = iget(sb, ino);
 	if (!inode)
 		goto out_ino;

 	PROC_I(inode)->fd = 0;
 	PROC_I(inode)->pde = de;
 	if (de) {
 		if (de->mode) {
 			inode->i_mode = de->mode;
 			inode->i_uid = de->uid;
 			inode->i_gid = de->gid;
 		}
 		if (de->size)
 			inode->i_size = de->size;
 		if (de->nlink)
 			inode->i_nlink = de->nlink;
 		if (de->proc_iops)
 			inode->i_op = de->proc_iops;
 		if (de->proc_fops) {
 			if (S_ISREG(inode->i_mode)) {
 #ifdef CONFIG_COMPAT
 				if (!de->proc_fops->compat_ioctl)
 					inode->i_fop =
 						&proc_reg_file_ops_no_compat;
 				else
 #endif
 					inode->i_fop = &proc_reg_file_ops;
 			}
 			else
 				inode->i_fop = de->proc_fops;
 		}
 	}

 	return inode;

 out_ino:
 	if (de != NULL)
 		module_put(de->owner);
 out_mod:
 	return NULL;
 }

 int proc_fill_super(struct super_block *s)
 {
 	struct inode * root_inode;

 	s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
 	s->s_blocksize = 1024;
 	s->s_blocksize_bits = 10;
 	s->s_magic = PROC_SUPER_MAGIC;
 	s->s_op = &proc_sops;
 	s->s_time_gran = 1;

 	de_get(&proc_root);
 	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
 	if (!root_inode)
 		goto out_no_root;
 	root_inode->i_uid = 0;
 	root_inode->i_gid = 0;
 	s->s_root = d_alloc_root(root_inode);
 	if (!s->s_root)
 		goto out_no_root;
 	return 0;

 out_no_root:
 	printk("proc_read_super: get root inode failed\n");
 	iput(root_inode);
 	de_put(&proc_root);
 	return -ENOMEM;
 }
 MODULE_LICENSE("GPL");
	/*
	* linux/fs/proc/inode.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*/

	#include <linux/time.h>
	#include <linux/proc_fs.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/string.h>
	#include <linux/stat.h>
	#include <linux/completion.h>
	#include <linux/poll.h>
	#include <linux/file.h>
	#include <linux/limits.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/smp_lock.h>

	#include <asm/system.h>
	#include <asm/uaccess.h>

	#include "internal.h"

	struct proc_dir_entry de_get(struct proc_dir_entry de)
	{
	if (de)
	atomic_inc(&de->count);
	return de;
	}

	/*
	* Decrements the use count and checks for deferred deletion.
	*/
	void de_put(struct proc_dir_entry *de)
	{
	if (de) {
	lock_kernel();
	if (!atomic_read(&de->count)) {
	printk("de_put: entry %s already free!\n", de->name);
	unlock_kernel();
	return;
	}

	if (atomic_dec_and_test(&de->count)) {
	if (de->deleted) {
	printk("de_put: deferred delete of %s\n",
	de->name);
	free_proc_entry(de);
	}
	}
	unlock_kernel();
	}
	}

	/*
	* Decrement the use count of the proc_dir_entry.
	*/
	static void proc_delete_inode(struct inode *inode)
	{
	struct proc_dir_entry *de;

	truncate_inode_pages(&inode->i_data, 0);

	/* Stop tracking associated processes */
	put_pid(PROC_I(inode)->pid);

	/* Let go of any associated proc directory entry */
	de = PROC_I(inode)->pde;
	if (de) {
	if (de->owner)
	module_put(de->owner);
	de_put(de);
	}
	clear_inode(inode);
	}

	struct vfsmount *proc_mnt;

	static void proc_read_inode(struct inode * inode)
	{
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	}

	static struct kmem_cache * proc_inode_cachep;

	static struct inode proc_alloc_inode(struct super_block sb)
	{
	struct proc_inode *ei;
	struct inode *inode;

	ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
	if (!ei)
	return NULL;
	ei->pid = NULL;
	ei->fd = 0;
	ei->op.proc_get_link = NULL;
	ei->pde = NULL;
	inode = &ei->vfs_inode;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	return inode;
	}

	static void proc_destroy_inode(struct inode *inode)
	{
	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
	}

	static void init_once(struct kmem_cache * cachep, void *foo)
	{
	struct proc_inode ei = (struct proc_inode ) foo;

	inode_init_once(&ei->vfs_inode);
	}

	int __init proc_init_inodecache(void)
	{
	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
	sizeof(struct proc_inode),
	0, (SLAB_RECLAIM_ACCOUNT\|
	SLAB_MEM_SPREAD\|SLAB_PANIC),
	init_once);
	return 0;
	}

	static int proc_remount(struct super_block sb, int flags, char *data)
	{
	*flags \|= MS_NODIRATIME;
	return 0;
	}

	static const struct super_operations proc_sops = {
	.alloc_inode = proc_alloc_inode,
	.destroy_inode = proc_destroy_inode,
	.read_inode = proc_read_inode,
	.drop_inode = generic_delete_inode,
	.delete_inode = proc_delete_inode,
	.statfs = simple_statfs,
	.remount_fs = proc_remount,
	};

	static void pde_users_dec(struct proc_dir_entry *pde)
	{
	spin_lock(&pde->pde_unload_lock);
	pde->pde_users--;
	if (pde->pde_unload_completion && pde->pde_users == 0)
	complete(pde->pde_unload_completion);
	spin_unlock(&pde->pde_unload_lock);
	}

	static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	loff_t rv = -EINVAL;
	loff_t (llseek)(struct file , loff_t, int);

	spin_lock(&pde->pde_unload_lock);
	/*
	* remove_proc_entry() is going to delete PDE (as part of module
	* cleanup sequence). No new callers into module allowed.
	*/
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	/*
	* Bump refcount so that remove_proc_entry will wail for ->llseek to
	* complete.
	*/
	pde->pde_users++;
	/*
	* Save function pointer under lock, to protect against ->proc_fops
	* NULL'ifying right after ->pde_unload_lock is dropped.
	*/
	llseek = pde->proc_fops->llseek;
	spin_unlock(&pde->pde_unload_lock);

	if (!llseek)
	llseek = default_llseek;
	rv = llseek(file, offset, whence);

	pde_users_dec(pde);
	return rv;
	}

	static ssize_t proc_reg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	ssize_t rv = -EIO;
	ssize_t (read)(struct file , char __user , size_t, loff_t );

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	read = pde->proc_fops->read;
	spin_unlock(&pde->pde_unload_lock);

	if (read)
	rv = read(file, buf, count, ppos);

	pde_users_dec(pde);
	return rv;
	}

	static ssize_t proc_reg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	ssize_t rv = -EIO;
	ssize_t (write)(struct file , const char __user , size_t, loff_t );

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	write = pde->proc_fops->write;
	spin_unlock(&pde->pde_unload_lock);

	if (write)
	rv = write(file, buf, count, ppos);

	pde_users_dec(pde);
	return rv;
	}

	static unsigned int proc_reg_poll(struct file file, struct poll_table_struct pts)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	unsigned int rv = DEFAULT_POLLMASK;
	unsigned int (poll)(struct file , struct poll_table_struct *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	poll = pde->proc_fops->poll;
	spin_unlock(&pde->pde_unload_lock);

	if (poll)
	rv = poll(file, pts);

	pde_users_dec(pde);
	return rv;
	}

	static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	long rv = -ENOTTY;
	long (unlocked_ioctl)(struct file , unsigned int, unsigned long);
	int (ioctl)(struct inode , struct file *, unsigned int, unsigned long);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
	ioctl = pde->proc_fops->ioctl;
	spin_unlock(&pde->pde_unload_lock);

	if (unlocked_ioctl) {
	rv = unlocked_ioctl(file, cmd, arg);
	if (rv == -ENOIOCTLCMD)
	rv = -EINVAL;
	} else if (ioctl) {
	lock_kernel();
	rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
	unlock_kernel();
	}

	pde_users_dec(pde);
	return rv;
	}

	#ifdef CONFIG_COMPAT
	static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	long rv = -ENOTTY;
	long (compat_ioctl)(struct file , unsigned int, unsigned long);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	compat_ioctl = pde->proc_fops->compat_ioctl;
	spin_unlock(&pde->pde_unload_lock);

	if (compat_ioctl)
	rv = compat_ioctl(file, cmd, arg);

	pde_users_dec(pde);
	return rv;
	}
	#endif

	static int proc_reg_mmap(struct file file, struct vm_area_struct vma)
	{
	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	int rv = -EIO;
	int (mmap)(struct file , struct vm_area_struct *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	mmap = pde->proc_fops->mmap;
	spin_unlock(&pde->pde_unload_lock);

	if (mmap)
	rv = mmap(file, vma);

	pde_users_dec(pde);
	return rv;
	}

	static int proc_reg_open(struct inode inode, struct file file)
	{
	struct proc_dir_entry *pde = PDE(inode);
	int rv = 0;
	int (open)(struct inode , struct file *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	open = pde->proc_fops->open;
	spin_unlock(&pde->pde_unload_lock);

	if (open)
	rv = open(inode, file);

	pde_users_dec(pde);
	return rv;
	}

	static int proc_reg_release(struct inode inode, struct file file)
	{
	struct proc_dir_entry *pde = PDE(inode);
	int rv = 0;
	int (release)(struct inode , struct file *);

	spin_lock(&pde->pde_unload_lock);
	if (!pde->proc_fops) {
	spin_unlock(&pde->pde_unload_lock);
	return rv;
	}
	pde->pde_users++;
	release = pde->proc_fops->release;
	spin_unlock(&pde->pde_unload_lock);

	if (release)
	rv = release(inode, file);

	pde_users_dec(pde);
	return rv;
	}

	static const struct file_operations proc_reg_file_ops = {
	.llseek = proc_reg_llseek,
	.read = proc_reg_read,
	.write = proc_reg_write,
	.poll = proc_reg_poll,
	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	#ifdef CONFIG_COMPAT
	.compat_ioctl = proc_reg_compat_ioctl,
	#endif
	.mmap = proc_reg_mmap,
	.open = proc_reg_open,
	.release = proc_reg_release,
	};

	#ifdef CONFIG_COMPAT
	static const struct file_operations proc_reg_file_ops_no_compat = {
	.llseek = proc_reg_llseek,
	.read = proc_reg_read,
	.write = proc_reg_write,
	.poll = proc_reg_poll,
	.unlocked_ioctl = proc_reg_unlocked_ioctl,
	.mmap = proc_reg_mmap,
	.open = proc_reg_open,
	.release = proc_reg_release,
	};
	#endif

	struct inode proc_get_inode(struct super_block sb, unsigned int ino,
	struct proc_dir_entry *de)
	{
	struct inode * inode;

	if (de != NULL && !try_module_get(de->owner))
	goto out_mod;

	inode = iget(sb, ino);
	if (!inode)
	goto out_ino;

	PROC_I(inode)->fd = 0;
	PROC_I(inode)->pde = de;
	if (de) {
	if (de->mode) {
	inode->i_mode = de->mode;
	inode->i_uid = de->uid;
	inode->i_gid = de->gid;
	}
	if (de->size)
	inode->i_size = de->size;
	if (de->nlink)
	inode->i_nlink = de->nlink;
	if (de->proc_iops)
	inode->i_op = de->proc_iops;
	if (de->proc_fops) {
	if (S_ISREG(inode->i_mode)) {
	#ifdef CONFIG_COMPAT
	if (!de->proc_fops->compat_ioctl)
	inode->i_fop =
	&proc_reg_file_ops_no_compat;
	else
	#endif
	inode->i_fop = &proc_reg_file_ops;
	}
	else
	inode->i_fop = de->proc_fops;
	}
	}

	return inode;

	out_ino:
	if (de != NULL)
	module_put(de->owner);
	out_mod:
	return NULL;
	}

	int proc_fill_super(struct super_block *s)
	{
	struct inode * root_inode;

	s->s_flags \|= MS_NODIRATIME \| MS_NOSUID \| MS_NOEXEC;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = PROC_SUPER_MAGIC;
	s->s_op = &proc_sops;
	s->s_time_gran = 1;

	de_get(&proc_root);
	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
	if (!root_inode)
	goto out_no_root;
	root_inode->i_uid = 0;
	root_inode->i_gid = 0;
	s->s_root = d_alloc_root(root_inode);
	if (!s->s_root)
	goto out_no_root;
	return 0;

	out_no_root:
	printk("proc_read_super: get root inode failed\n");
	iput(root_inode);
	de_put(&proc_root);
	return -ENOMEM;
	}
	MODULE_LICENSE("GPL");