466 lines
10 KiB
C
466 lines
10 KiB
C
/*
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* linux/fs/proc/inode.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/completion.h>
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#include <linux/poll.h>
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#include <linux/file.h>
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#include <linux/limits.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/smp_lock.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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struct proc_dir_entry *de_get(struct proc_dir_entry *de)
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{
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atomic_inc(&de->count);
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return de;
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}
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/*
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* Decrements the use count and checks for deferred deletion.
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*/
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void de_put(struct proc_dir_entry *de)
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{
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lock_kernel();
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if (!atomic_read(&de->count)) {
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printk("de_put: entry %s already free!\n", de->name);
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unlock_kernel();
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return;
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}
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if (atomic_dec_and_test(&de->count))
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free_proc_entry(de);
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unlock_kernel();
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}
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/*
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* Decrement the use count of the proc_dir_entry.
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*/
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static void proc_delete_inode(struct inode *inode)
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{
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struct proc_dir_entry *de;
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truncate_inode_pages(&inode->i_data, 0);
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/* Stop tracking associated processes */
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put_pid(PROC_I(inode)->pid);
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/* Let go of any associated proc directory entry */
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de = PROC_I(inode)->pde;
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if (de) {
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if (de->owner)
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module_put(de->owner);
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de_put(de);
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}
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clear_inode(inode);
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}
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struct vfsmount *proc_mnt;
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static struct kmem_cache * proc_inode_cachep;
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static struct inode *proc_alloc_inode(struct super_block *sb)
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{
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struct proc_inode *ei;
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struct inode *inode;
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ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
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if (!ei)
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return NULL;
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ei->pid = NULL;
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ei->fd = 0;
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ei->op.proc_get_link = NULL;
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ei->pde = NULL;
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inode = &ei->vfs_inode;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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return inode;
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}
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static void proc_destroy_inode(struct inode *inode)
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{
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kmem_cache_free(proc_inode_cachep, PROC_I(inode));
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}
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static void init_once(struct kmem_cache * cachep, void *foo)
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{
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struct proc_inode *ei = (struct proc_inode *) foo;
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inode_init_once(&ei->vfs_inode);
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}
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int __init proc_init_inodecache(void)
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{
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proc_inode_cachep = kmem_cache_create("proc_inode_cache",
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sizeof(struct proc_inode),
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0, (SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD|SLAB_PANIC),
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init_once);
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return 0;
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}
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static int proc_remount(struct super_block *sb, int *flags, char *data)
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{
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*flags |= MS_NODIRATIME;
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return 0;
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}
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static const struct super_operations proc_sops = {
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.alloc_inode = proc_alloc_inode,
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.destroy_inode = proc_destroy_inode,
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.drop_inode = generic_delete_inode,
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.delete_inode = proc_delete_inode,
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.statfs = simple_statfs,
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.remount_fs = proc_remount,
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};
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static void pde_users_dec(struct proc_dir_entry *pde)
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{
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spin_lock(&pde->pde_unload_lock);
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pde->pde_users--;
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if (pde->pde_unload_completion && pde->pde_users == 0)
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complete(pde->pde_unload_completion);
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spin_unlock(&pde->pde_unload_lock);
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}
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static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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loff_t rv = -EINVAL;
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loff_t (*llseek)(struct file *, loff_t, int);
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spin_lock(&pde->pde_unload_lock);
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/*
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* remove_proc_entry() is going to delete PDE (as part of module
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* cleanup sequence). No new callers into module allowed.
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*/
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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/*
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* Bump refcount so that remove_proc_entry will wail for ->llseek to
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* complete.
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*/
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pde->pde_users++;
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/*
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* Save function pointer under lock, to protect against ->proc_fops
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* NULL'ifying right after ->pde_unload_lock is dropped.
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*/
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llseek = pde->proc_fops->llseek;
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spin_unlock(&pde->pde_unload_lock);
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if (!llseek)
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llseek = default_llseek;
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rv = llseek(file, offset, whence);
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pde_users_dec(pde);
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return rv;
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}
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static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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ssize_t rv = -EIO;
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ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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read = pde->proc_fops->read;
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spin_unlock(&pde->pde_unload_lock);
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if (read)
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rv = read(file, buf, count, ppos);
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pde_users_dec(pde);
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return rv;
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}
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static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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ssize_t rv = -EIO;
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ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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write = pde->proc_fops->write;
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spin_unlock(&pde->pde_unload_lock);
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if (write)
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rv = write(file, buf, count, ppos);
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pde_users_dec(pde);
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return rv;
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}
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static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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unsigned int rv = DEFAULT_POLLMASK;
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unsigned int (*poll)(struct file *, struct poll_table_struct *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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poll = pde->proc_fops->poll;
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spin_unlock(&pde->pde_unload_lock);
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if (poll)
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rv = poll(file, pts);
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pde_users_dec(pde);
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return rv;
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}
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static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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long rv = -ENOTTY;
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long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long);
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int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
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ioctl = pde->proc_fops->ioctl;
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spin_unlock(&pde->pde_unload_lock);
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if (unlocked_ioctl) {
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rv = unlocked_ioctl(file, cmd, arg);
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if (rv == -ENOIOCTLCMD)
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rv = -EINVAL;
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} else if (ioctl) {
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lock_kernel();
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rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
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unlock_kernel();
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}
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pde_users_dec(pde);
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return rv;
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}
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#ifdef CONFIG_COMPAT
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static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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long rv = -ENOTTY;
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long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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compat_ioctl = pde->proc_fops->compat_ioctl;
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spin_unlock(&pde->pde_unload_lock);
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if (compat_ioctl)
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rv = compat_ioctl(file, cmd, arg);
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pde_users_dec(pde);
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return rv;
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}
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#endif
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static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
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int rv = -EIO;
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int (*mmap)(struct file *, struct vm_area_struct *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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mmap = pde->proc_fops->mmap;
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spin_unlock(&pde->pde_unload_lock);
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if (mmap)
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rv = mmap(file, vma);
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pde_users_dec(pde);
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return rv;
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}
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static int proc_reg_open(struct inode *inode, struct file *file)
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{
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struct proc_dir_entry *pde = PDE(inode);
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int rv = 0;
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int (*open)(struct inode *, struct file *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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open = pde->proc_fops->open;
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spin_unlock(&pde->pde_unload_lock);
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if (open)
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rv = open(inode, file);
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pde_users_dec(pde);
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return rv;
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}
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static int proc_reg_release(struct inode *inode, struct file *file)
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{
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struct proc_dir_entry *pde = PDE(inode);
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int rv = 0;
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int (*release)(struct inode *, struct file *);
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spin_lock(&pde->pde_unload_lock);
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if (!pde->proc_fops) {
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spin_unlock(&pde->pde_unload_lock);
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return rv;
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}
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pde->pde_users++;
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release = pde->proc_fops->release;
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spin_unlock(&pde->pde_unload_lock);
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if (release)
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rv = release(inode, file);
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pde_users_dec(pde);
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return rv;
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}
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static const struct file_operations proc_reg_file_ops = {
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.llseek = proc_reg_llseek,
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.read = proc_reg_read,
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.write = proc_reg_write,
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.poll = proc_reg_poll,
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.unlocked_ioctl = proc_reg_unlocked_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = proc_reg_compat_ioctl,
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#endif
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.mmap = proc_reg_mmap,
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.open = proc_reg_open,
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.release = proc_reg_release,
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};
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#ifdef CONFIG_COMPAT
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static const struct file_operations proc_reg_file_ops_no_compat = {
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.llseek = proc_reg_llseek,
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.read = proc_reg_read,
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.write = proc_reg_write,
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.poll = proc_reg_poll,
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.unlocked_ioctl = proc_reg_unlocked_ioctl,
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.mmap = proc_reg_mmap,
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.open = proc_reg_open,
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.release = proc_reg_release,
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};
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#endif
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struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
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struct proc_dir_entry *de)
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{
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struct inode * inode;
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if (!try_module_get(de->owner))
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goto out_mod;
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inode = iget_locked(sb, ino);
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if (!inode)
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goto out_ino;
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if (inode->i_state & I_NEW) {
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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PROC_I(inode)->fd = 0;
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PROC_I(inode)->pde = de;
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if (de->mode) {
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inode->i_mode = de->mode;
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inode->i_uid = de->uid;
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inode->i_gid = de->gid;
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}
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if (de->size)
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inode->i_size = de->size;
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if (de->nlink)
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inode->i_nlink = de->nlink;
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if (de->proc_iops)
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inode->i_op = de->proc_iops;
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if (de->proc_fops) {
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if (S_ISREG(inode->i_mode)) {
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#ifdef CONFIG_COMPAT
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if (!de->proc_fops->compat_ioctl)
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inode->i_fop =
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&proc_reg_file_ops_no_compat;
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else
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#endif
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inode->i_fop = &proc_reg_file_ops;
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} else {
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inode->i_fop = de->proc_fops;
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}
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}
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unlock_new_inode(inode);
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} else
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module_put(de->owner);
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return inode;
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out_ino:
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module_put(de->owner);
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out_mod:
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return NULL;
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}
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int proc_fill_super(struct super_block *s)
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{
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struct inode * root_inode;
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s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
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s->s_blocksize = 1024;
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s->s_blocksize_bits = 10;
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s->s_magic = PROC_SUPER_MAGIC;
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s->s_op = &proc_sops;
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s->s_time_gran = 1;
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de_get(&proc_root);
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root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
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if (!root_inode)
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goto out_no_root;
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root_inode->i_uid = 0;
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root_inode->i_gid = 0;
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s->s_root = d_alloc_root(root_inode);
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if (!s->s_root)
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goto out_no_root;
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return 0;
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out_no_root:
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printk("proc_read_super: get root inode failed\n");
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iput(root_inode);
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de_put(&proc_root);
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return -ENOMEM;
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}
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