On Fri, 2020-05-29 at 13:16 -0700, Jakub Kicinski wrote:
> On Fri, 29 May 2020 12:46:40 -0700 Saeed Mahameed wrote:
> > /* Re-sync */
> > +static struct mlx5_wqe_ctrl_seg *
> > +resync_post_get_progress_params(struct mlx5e_icosq *sq,
> > + struct mlx5e_ktls_offload_context_rx
> > *priv_rx)
> > +{
> > + struct mlx5e_ktls_rx_resync_ctx *resync = &priv_rx->resync;
> > + struct mlx5e_get_tls_progress_params_wqe *wqe;
> > + struct mlx5_wqe_ctrl_seg *cseg;
> > + struct mlx5_seg_get_psv *psv;
> > + u16 pi;
> > +
> > + dma_sync_single_for_device(resync->priv->mdev->device,
> > + resync->dma_addr,
> > + PROGRESS_PARAMS_PADDED_SIZE,
> > + DMA_FROM_DEVICE);
> > + BUILD_BUG_ON(MLX5E_KTLS_GET_PROGRESS_WQEBBS != 1);
> > + if (unlikely(!mlx5e_wqc_has_room_for(&sq->wq, sq->cc, sq->pc,
> > 1)))
> > + return ERR_PTR(-ENOSPC);
>
> I thought you said that resync requests are guaranteed to never fail?
>
I didn't say that :), maybe tariq did say this before my review,
but basically with the current mlx5 arch, it is impossible to guarantee
this unless we open 1 service queue per ktls offloads and that is going
to be an overkill!
This is a rare corner case anyway, where more than 1k tcp connections
sharing the same RX ring will request resync at the same exact moment.
> > + pi = mlx5e_icosq_get_next_pi(sq, 1);
> > + wqe = MLX5E_TLS_FETCH_GET_PROGRESS_PARAMS_WQE(sq, pi);
> > +
> > +#define GET_PSV_DS_CNT (DIV_ROUND_UP(sizeof(*wqe),
> > MLX5_SEND_WQE_DS))
> > +
> > + cseg = &wqe->ctrl;
> > + cseg->opmod_idx_opcode =
> > + cpu_to_be32((sq->pc << 8) | MLX5_OPCODE_GET_PSV |
> > + (MLX5_OPC_MOD_TLS_TIR_PROGRESS_PARAMS <<
> > 24));
> > + cseg->qpn_ds =
> > + cpu_to_be32((sq->sqn << MLX5_WQE_CTRL_QPN_SHIFT) |
> > GET_PSV_DS_CNT);
> > +
> > + psv = &wqe->psv;
> > + psv->num_psv = 1 << 4;
> > + psv->l_key = sq->channel->mkey_be;
> > + psv->psv_index[0] = cpu_to_be32(priv_rx->tirn);
> > + psv->va = cpu_to_be64(priv_rx->resync.dma_addr);
> > +
> > + icosq_fill_wi(sq, pi, MLX5E_ICOSQ_WQE_GET_PSV_TLS, 1, priv_rx);
> > + sq->pc++;
> > +
> > + return cseg;
> > +}
