On Thu, 2017-07-13 at 11:20 -0600, Jason Gunthorpe wrote: > On Thu, Jul 13, 2017 at 12:51:16AM -0700, Christoph Hellwig wrote: > > > if (qp->qp_cap_cache & MLX5_RX_CSUM_VALID) > > > - wc->wc_flags |= (!!(cqe->hds_ip_ext & MLX5_CQE_L4_OK) & > > > - !!(cqe->hds_ip_ext & MLX5_CQE_L3_OK) & > > > - (get_cqe_l3_hdr_type(cqe) == > > > - MLX5_CQE_L3_HDR_TYPE_IPV4)) << > > > - IBV_WC_IP_CSUM_OK_SHIFT; > > > + wc->wc_flags |= > > > + ((bool)(cqe->hds_ip_ext & MLX5_CQE_L4_OK) & > > > + (bool)(cqe->hds_ip_ext & MLX5_CQE_L3_OK) & > > > + (get_cqe_l3_hdr_type(cqe) == > > > + MLX5_CQE_L3_HDR_TYPE_IPV4)) > > > + << IBV_WC_IP_CSUM_OK_SHIFT; > > > > Meh. This code is complete crap. Please factor it out into a little > > helper that mere humans can read first. And then replace the odd ^ used > > as && with proper if constructs and all should make much more sense. > > As far as I could make out, this ugly thing is designed like this for > performance. Hello Jason, How about using an expression like the below to avoid that branches get inserted for testing the MLX5_CQE_L4_OK and MLX5_CQE_L3_OK flags? (cqe->hds_ip_ext & (MLX5_CQE_L4_OK | MLX5_CQE_L3_OK)) == MLX5_CQE_L4_OK | MLX5_CQE_L3_OK Bart.-- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
