configfs: return -ENAMETOOLONG earlier in configfs_lookup

mainline inclusion
from mainline-v5.15-rc1
commit 417b962d
category: bugfix
bugzilla: 187567, https://gitee.com/openeuler/kernel/issues/I5PK1G
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/configfs/dir.c?h=v6.0-rc3&id=417b962ddeca2b70eb72d28c87541bdad4e234f8

--------------------------------

Just like most other file systems: get the simple checks out of the
way first.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NZhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/configfs/dir.c

@@ -465,6 +465,9 @@ static struct dentry * configfs_lookup(struct inode *dir,
 	int found = 0;
 	int err;
 
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
 	/*
 	 * Fake invisibility if dir belongs to a group/default groups hierarchy
 	 * being attached
@@ -495,8 +498,6 @@ static struct dentry * configfs_lookup(struct inode *dir,
 		 * If it doesn't exist and it isn't a NOT_PINNED item,
 		 * it must be negative.
 		 */
-		if (dentry->d_name.len > NAME_MAX)
-			return ERR_PTR(-ENAMETOOLONG);
 		d_add(dentry, NULL);
 		return NULL;
 	}