+ 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 *);
+ int (*release)(struct inode *, struct file *);
+ struct pde_opener *pdeo;
+
+ /*
+ * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
+ * sequence. ->release won't be called because ->proc_fops will be
+ * cleared. Depending on complexity of ->release, consequences vary.
+ *
+ * We can't wait for mercy when close will be done for real, it's
+ * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
+ * by hand in remove_proc_entry(). For this, save opener's credentials
+ * for later.
+ */
+ pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
+ if (!pdeo)
+ return -ENOMEM;
+
+ spin_lock(&pde->pde_unload_lock);
+ if (!pde->proc_fops) {
+ spin_unlock(&pde->pde_unload_lock);
+ kfree(pdeo);
+ return -EINVAL;
+ }
+ pde->pde_users++;
+ open = pde->proc_fops->open;
+ release = pde->proc_fops->release;
+ spin_unlock(&pde->pde_unload_lock);
+
+ if (open)
+ rv = open(inode, file);
+
+ spin_lock(&pde->pde_unload_lock);
+ if (rv == 0 && release) {
+ /* To know what to release. */
+ pdeo->inode = inode;
+ pdeo->file = file;
+ /* Strictly for "too late" ->release in proc_reg_release(). */
+ pdeo->release = release;
+ list_add(&pdeo->lh, &pde->pde_openers);
+ } else
+ kfree(pdeo);
+ __pde_users_dec(pde);
+ spin_unlock(&pde->pde_unload_lock);
+ return rv;
+}
+
+static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde,
+ struct inode *inode, struct file *file)
+{
+ struct pde_opener *pdeo;
+
+ list_for_each_entry(pdeo, &pde->pde_openers, lh) {
+ if (pdeo->inode == inode && pdeo->file == file)
+ return pdeo;
+ }
+ return NULL;
+}
+
+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 *);
+ struct pde_opener *pdeo;
+
+ spin_lock(&pde->pde_unload_lock);
+ pdeo = find_pde_opener(pde, inode, file);
+ if (!pde->proc_fops) {
+ /*
+ * Can't simply exit, __fput() will think that everything is OK,
+ * and move on to freeing struct file. remove_proc_entry() will
+ * find slacker in opener's list and will try to do non-trivial
+ * things with struct file. Therefore, remove opener from list.
+ *
+ * But if opener is removed from list, who will ->release it?
+ */
+ if (pdeo) {
+ list_del(&pdeo->lh);
+ spin_unlock(&pde->pde_unload_lock);
+ rv = pdeo->release(inode, file);
+ kfree(pdeo);
+ } else
+ spin_unlock(&pde->pde_unload_lock);
+ return rv;
+ }
+ pde->pde_users++;
+ release = pde->proc_fops->release;
+ if (pdeo) {
+ list_del(&pdeo->lh);
+ kfree(pdeo);
+ }
+ 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 (!try_module_get(de->owner))