smb: server: let smb_direct_post_send_data() return data_length

This make it easier moving to common code shared with the client.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: metze-samba

fs/smb/server/transport_rdma.c

@@ -944,7 +944,7 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
 			goto flush_failed;
 	}
 
-	return 0;
+	return data_length;
 err:
 	smbdirect_connection_free_send_io(msg);
 flush_failed:
@@ -1000,7 +1000,7 @@ static int smb_direct_send_iter(struct smbdirect_socket *sc,
 						&send_ctx,
 						iter,
 						iov_iter_count(iter));
-		if (unlikely(ret)) {
+		if (unlikely(ret < 0)) {
 			error = ret;
 			break;
 		}