diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index e59094981175..37be6e226d1b 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -552,9 +552,8 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
 	    && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
 		rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
 		scat = &rm->data.op_sg[sg];
-		ret = sizeof(struct rds_header) + RDS_CONG_MAP_BYTES;
-		ret = min_t(int, ret, scat->length - conn->c_xmit_data_off);
-		return ret;
+		ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length);
+		return sizeof(struct rds_header) + ret;
 	}
 
 	/* FIXME we may overallocate here */