ovl: avoid pointless cred reference count bump

security_inode_copy_up() allocates a set of new credentials and has
taken a reference count.

Link: https://lore.kernel.org/r/20241125-work-cred-v2-18-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/overlayfs/copy_up.c

@@ -741,15 +741,15 @@ static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
 		return err;
 
 	if (cc->new)
-		cc->old = override_creds(get_new_cred(cc->new));
+		cc->old = override_creds(cc->new);
 
 	return 0;
 }
 
 static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
 {
 	if (cc->new) {
-		put_cred(revert_creds(cc->old));
+		revert_creds(cc->old);
 		put_cred(cc->new);
 	}
 }