diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index f2be44d..bfb8a23 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -130,7 +130,7 @@
 {
 	char s[12];
 	struct dentry *root = devpts_root;
-	down(&root->d_inode->i_sem);
+	mutex_lock(&root->d_inode->i_mutex);
 	return lookup_one_len(s, root, sprintf(s, "%d", num));
 }
 
@@ -161,7 +161,7 @@
 	if (!IS_ERR(dentry) && !dentry->d_inode)
 		d_instantiate(dentry, inode);
 
-	up(&devpts_root->d_inode->i_sem);
+	mutex_unlock(&devpts_root->d_inode->i_mutex);
 
 	return 0;
 }
@@ -178,7 +178,7 @@
 		dput(dentry);
 	}
 
-	up(&devpts_root->d_inode->i_sem);
+	mutex_unlock(&devpts_root->d_inode->i_mutex);
 
 	return tty;
 }
@@ -196,7 +196,7 @@
 		}
 		dput(dentry);
 	}
-	up(&devpts_root->d_inode->i_sem);
+	mutex_unlock(&devpts_root->d_inode->i_mutex);
 }
 
 static int __init init_devpts_fs(void)