[PATCH v2 13/16] overlayfs/readdir: Convert to cred_guard()

[Vinicius Costa Gomes <vinicius.gomes@intel.com>]

Replace the override_creds_light()/revert_creds_light() pairs of
operations with cred_guard()/cred_scoped_guard().

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 fs/overlayfs/readdir.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index c8bf681f5cf0..41e01fe3ae4a 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -273,9 +273,8 @@ static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data
 	int err;
 	struct ovl_cache_entry *p;
 	struct dentry *dentry, *dir = path->dentry;
-	const struct cred *old_cred;
 
-	old_cred = ovl_override_creds_light(rdd->dentry->d_sb);
+	cred_guard(ovl_creds(rdd->dentry->d_sb));
 
 	err = down_write_killable(&dir->d_inode->i_rwsem);
 	if (!err) {
@@ -290,7 +289,6 @@ static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data
 		}
 		inode_unlock(dir->d_inode);
 	}
-	revert_creds_light(old_cred);
 
 	return err;
 }
@@ -753,10 +751,9 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 	struct dentry *dentry = file->f_path.dentry;
 	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct ovl_cache_entry *p;
-	const struct cred *old_cred;
 	int err;
 
-	old_cred = ovl_override_creds_light(dentry->d_sb);
+	cred_guard(ovl_creds(dentry->d_sb));
 	if (!ctx->pos)
 		ovl_dir_reset(file);
 
@@ -808,7 +805,6 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 	}
 	err = 0;
 out:
-	revert_creds_light(old_cred);
 	return err;
 }
 
@@ -856,11 +852,9 @@ static struct file *ovl_dir_open_realfile(const struct file *file,
 					  const struct path *realpath)
 {
 	struct file *res;
-	const struct cred *old_cred;
 
-	old_cred = ovl_override_creds_light(file_inode(file)->i_sb);
+	cred_guard(ovl_creds(file_inode(file)->i_sb));
 	res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));
-	revert_creds_light(old_cred);
 
 	return res;
 }
@@ -983,11 +977,9 @@ int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
 	int err;
 	struct ovl_cache_entry *p, *n;
 	struct rb_root root = RB_ROOT;
-	const struct cred *old_cred;
 
-	old_cred = ovl_override_creds_light(dentry->d_sb);
+	cred_guard(ovl_creds(dentry->d_sb));
 	err = ovl_dir_read_merged(dentry, list, &root);
-	revert_creds_light(old_cred);
 	if (err)
 		return err;
 
-- 
2.46.0