vfs: do_last(): inline walk_component()

Copy walk_component() into do_lookup().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2200,6 +2200,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	int want_write = 0;
 	int acc_mode = op->acc_mode;
 	struct file *filp;
+	struct inode *inode;
 	int error;
 
 	nd->flags &= ~LOOKUP_PARENT;
@@ -2237,12 +2238,36 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 		if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
 			symlink_ok = 1;
 		/* we _can_ be in RCU mode here */
-		error = walk_component(nd, path, &nd->last, LAST_NORM,
-					!symlink_ok);
-		if (error < 0)
-			return ERR_PTR(error);
-		if (error) /* symlink */
+		error = lookup_fast(nd, &nd->last, path, &inode);
+		if (unlikely(error)) {
+			if (error < 0)
+				goto exit;
+
+			error = lookup_slow(nd, &nd->last, path);
+			if (error < 0)
+				goto exit;
+
+			inode = path->dentry->d_inode;
+		}
+		error = -ENOENT;
+		if (!inode) {
+			path_to_nameidata(path, nd);
+			goto exit;
+		}
+
+		if (should_follow_link(inode, !symlink_ok)) {
+			if (nd->flags & LOOKUP_RCU) {
+				if (unlikely(unlazy_walk(nd, path->dentry))) {
+					error = -ECHILD;
+					goto exit;
+				}
+			}
+			BUG_ON(inode != path->dentry->d_inode);
 			return NULL;
+		}
+		path_to_nameidata(path, nd);
+		nd->inode = inode;
+
 		/* sayonara */
 		error = complete_walk(nd);
 		if (error)