+#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
+static int mknod_ptmx(struct super_block *sb)
+{
+ int mode;
+ int rc = -ENOMEM;
+ struct dentry *dentry;
+ struct inode *inode;
+ struct dentry *root = sb->s_root;
+ struct pts_fs_info *fsi = DEVPTS_SB(sb);
+ struct pts_mount_opts *opts = &fsi->mount_opts;
+
+ mutex_lock(&root->d_inode->i_mutex);
+
+ /* If we have already created ptmx node, return */
+ if (fsi->ptmx_dentry) {
+ rc = 0;
+ goto out;
+ }
+
+ dentry = d_alloc_name(root, "ptmx");
+ if (!dentry) {
+ printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n");
+ goto out;
+ }
+
+ /*
+ * Create a new 'ptmx' node in this mount of devpts.
+ */
+ inode = new_inode(sb);
+ if (!inode) {
+ printk(KERN_ERR "Unable to alloc inode for ptmx node\n");
+ dput(dentry);
+ goto out;
+ }
+
+ inode->i_ino = 2;
+ inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+
+ mode = S_IFCHR|opts->ptmxmode;
+ init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2));
+
+ d_add(dentry, inode);
+
+ fsi->ptmx_dentry = dentry;
+ rc = 0;
+out:
+ mutex_unlock(&root->d_inode->i_mutex);
+ return rc;
+}
+
+static void update_ptmx_mode(struct pts_fs_info *fsi)
+{
+ struct inode *inode;
+ if (fsi->ptmx_dentry) {
+ inode = fsi->ptmx_dentry->d_inode;
+ inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
+ }
+}
+#else
+static inline void update_ptmx_mode(struct pts_fs_info *fsi)
+{
+ return;
+}
+#endif
+
+static int devpts_remount(struct super_block *sb, int *flags, char *data)
+{
+ int err;
+ struct pts_fs_info *fsi = DEVPTS_SB(sb);
+ struct pts_mount_opts *opts = &fsi->mount_opts;
+
+ err = parse_mount_options(data, PARSE_REMOUNT, opts);
+
+ /*
+ * parse_mount_options() restores options to default values
+ * before parsing and may have changed ptmxmode. So, update the
+ * mode in the inode too. Bogus options don't fail the remount,
+ * so do this even on error return.
+ */
+ update_ptmx_mode(fsi);
+
+ return err;
+}
+