RE: [PATCH 29/30] IB/mlx4: Create and use another QP1 for RoCEv2

Shachar Raindel
2015-02-19T16:11:03Z

> -----Original Message-----
> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-
> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Somnath Kotur
> Sent: Friday, February 20, 2015 12:03 AM
> To: roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Moni Shoua; Somnath Kotur
> Subject: [PATCH 29/30] IB/mlx4: Create and use another QP1 for RoCEv2
>
> From: Moni Shoua <monis-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>
> The mlx4 driver uses a special QP to implement the GSI QP. This kind of
> QP allows to build the InfiniBand headers in SW to be put before the
> payload that comes in with the WR. The mlx4 HW builds the packet,
> calculates the ICRC and puts it at the end of the payload. This ICRC
> calculation however depends on the QP configuration which is determined
> when QP is modified (roce_mode during INIT->RTR). On the other hand,
> ICRC
> verification when packet is received does to depend on this

The grammar in this sentence is broken. Generally speaking, it is hard to understand what the patch does and aim to do from this commit message.
Please rephrase.

> configuration.
> Therefore, using 2 GSI QPs for send (one for each RoCE version) and 1
> GSI QP for receive are required.
>
> Signed-off-by: Moni Shoua <monis-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Somnath Kotur <somnath.kotur-laKkSmNT4hbQT0dZR+AlfA@public.gmane.org>
> ---
> drivers/infiniband/hw/mlx4/mlx4_ib.h | 7 ++
> drivers/infiniband/hw/mlx4/qp.c | 154
> ++++++++++++++++++++++++++++++----
> 2 files changed, 143 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h
> b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> index 018bda6..a853330 100644
> --- a/drivers/infiniband/hw/mlx4/mlx4_ib.h
> +++ b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> @@ -159,11 +159,18 @@ struct mlx4_ib_wq {
> unsigned tail;
> };
>
> +enum {
> + MLX4_IB_QP_CREATE_ROCE_V2_GSI = IB_QP_CREATE_RESERVED_START
> +};
> +
> enum mlx4_ib_qp_flags {
> MLX4_IB_QP_LSO = IB_QP_CREATE_IPOIB_UD_LSO,
> MLX4_IB_QP_BLOCK_MULTICAST_LOOPBACK =
> IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK,
> MLX4_IB_QP_NETIF = IB_QP_CREATE_NETIF_QP,
> MLX4_IB_QP_CREATE_USE_GFP_NOIO = IB_QP_CREATE_USE_GFP_NOIO,
> +
> + /* Mellanox specific flags start from IB_QP_CREATE_RESERVED_START
> */
> + MLX4_IB_ROCE_V2_GSI_QP = MLX4_IB_QP_CREATE_ROCE_V2_GSI,

Why do you need 2 enums for this flag definition?
Also, the comment refers to IB_QP_CREATE_RESERVED_START, which is not appearing here.

> MLX4_IB_SRIOV_TUNNEL_QP = 1 << 30,
> MLX4_IB_SRIOV_SQP = 1 << 31,
> };
> diff --git a/drivers/infiniband/hw/mlx4/qp.c
> b/drivers/infiniband/hw/mlx4/qp.c
> index 9996527..161b933 100644
> --- a/drivers/infiniband/hw/mlx4/qp.c
> +++ b/drivers/infiniband/hw/mlx4/qp.c
> @@ -81,6 +81,7 @@ struct mlx4_ib_sqp {
> u32 send_psn;
> struct ib_ud_header ud_header;
> u8 header_buf[MLX4_IB_UD_HEADER_SIZE];
> + struct ib_qp *roce_v2_gsi;
> };
>
> enum {
> @@ -150,7 +151,10 @@ static int is_sqp(struct mlx4_ib_dev *dev, struct
> mlx4_ib_qp *qp)
> }
> }
> }
> - return proxy_sqp;
> + if (proxy_sqp)
> + return 1;
> +
> + return !!(qp->flags & MLX4_IB_ROCE_V2_GSI_QP);

What are the implications of this double-QP scheme in virtualization scenario?

> }
>
> /* used for INIT/CLOSE port logic */
> @@ -672,6 +676,7 @@ static int create_qp_common(struct mlx4_ib_dev *dev,
> struct ib_pd *pd,
> qp = &sqp->qp;
> qp->pri.vid = 0xFFFF;
> qp->alt.vid = 0xFFFF;
> + sqp->roce_v2_gsi = NULL;
> } else {
> qp = kzalloc(sizeof (struct mlx4_ib_qp), gfp);
> if (!qp)
> @@ -1029,9 +1034,17 @@ static void destroy_qp_common(struct mlx4_ib_dev
> *dev, struct mlx4_ib_qp *qp,
> del_gid_entries(qp);
> }
>
> -static u32 get_sqp_num(struct mlx4_ib_dev *dev, struct ib_qp_init_attr
> *attr)
> +static int get_sqp_num(struct mlx4_ib_dev *dev, struct ib_qp_init_attr
> *attr)
> {
> /* Native or PPF */
> + if ((!mlx4_is_mfunc(dev->dev) || mlx4_is_master(dev->dev)) &&
> + attr->create_flags & MLX4_IB_QP_CREATE_ROCE_V2_GSI) {
> + int sqpn;
> + int res = mlx4_qp_reserve_range(dev->dev, 1, 1, &sqpn, 0);
> +
> + return res ? -abs(res) : sqpn;

This seems wrong. Mlx4_qp_reserve_range returns either 0 (success) or negative errno value on error. The check here should therefore say "res ? res : sqpn;".

If you want, you can add a WARN_ON(res > 0); above it.

> + }
> +
> if (!mlx4_is_mfunc(dev->dev) ||
> (mlx4_is_master(dev->dev) &&
> attr->create_flags & MLX4_IB_SRIOV_SQP)) {
> @@ -1039,6 +1052,7 @@ static u32 get_sqp_num(struct mlx4_ib_dev *dev,
> struct ib_qp_init_attr *attr)
> (attr->qp_type == IB_QPT_SMI ? 0 : 2) +
> attr->port_num - 1;
> }
> +
> /* PF or VF -- creating proxies */
> if (attr->qp_type == IB_QPT_SMI)
> return dev->dev->caps.qp0_proxy[attr->port_num - 1];
> @@ -1046,9 +1060,9 @@ static u32 get_sqp_num(struct mlx4_ib_dev *dev,
> struct ib_qp_init_attr *attr)
> return dev->dev->caps.qp1_proxy[attr->port_num - 1];
> }
>
> -struct ib_qp *mlx4_ib_create_qp(struct ib_pd *pd,
> - struct ib_qp_init_attr *init_attr,
> - struct ib_udata *udata)
> +static struct ib_qp *_mlx4_ib_create_qp(struct ib_pd *pd,
> + struct ib_qp_init_attr *init_attr,
> + struct ib_udata *udata)
> {
> struct mlx4_ib_qp *qp = NULL;
> int err;
> @@ -1066,6 +1080,7 @@ struct ib_qp *mlx4_ib_create_qp(struct ib_pd *pd,
> MLX4_IB_SRIOV_TUNNEL_QP |
> MLX4_IB_SRIOV_SQP |
> MLX4_IB_QP_NETIF |
> + MLX4_IB_QP_CREATE_ROCE_V2_GSI |
> MLX4_IB_QP_CREATE_USE_GFP_NOIO))
> return ERR_PTR(-EINVAL);
>
> @@ -1074,13 +1089,19 @@ struct ib_qp *mlx4_ib_create_qp(struct ib_pd
> *pd,
> return ERR_PTR(-EINVAL);
> }
>
> - if (init_attr->create_flags &&
> - (udata ||
> - ((init_attr->create_flags & ~(MLX4_IB_SRIOV_SQP |
> MLX4_IB_QP_CREATE_USE_GFP_NOIO)) &&
> - init_attr->qp_type != IB_QPT_UD) ||
> - ((init_attr->create_flags & MLX4_IB_SRIOV_SQP) &&
> - init_attr->qp_type > IB_QPT_GSI)))
> - return ERR_PTR(-EINVAL);
> + if (init_attr->create_flags) {
> + /* userspace is not allowed to set create flags */
> + if (udata)
> + return ERR_PTR(-EINVAL);
> +
> + if ((init_attr->create_flags & ~(MLX4_IB_SRIOV_SQP |
> MLX4_IB_QP_CREATE_USE_GFP_NOIO) &&
> + init_attr->qp_type != IB_QPT_UD) &&

You changed the logic of the condition here - you switched from OR between the clauses to an AND.
You can just split each verification to a separate if statement, like you did with udata. Please also add a justification for the condition when doing so.

> + (init_attr->create_flags & MLX4_IB_SRIOV_SQP &&
> + init_attr->qp_type > IB_QPT_GSI) &&
> + (init_attr->create_flags & MLX4_IB_QP_CREATE_ROCE_V2_GSI
> &&
> + init_attr->qp_type != IB_QPT_GSI))
> + return ERR_PTR(-EINVAL);
> + }
>
> switch (init_attr->qp_type) {
> case IB_QPT_XRC_TGT:
> @@ -1117,19 +1138,25 @@ struct ib_qp *mlx4_ib_create_qp(struct ib_pd
> *pd,
> case IB_QPT_SMI:
> case IB_QPT_GSI:
> {
> + int sqpn;
> +
> /* Userspace is not allowed to create special QPs: */
> if (udata)
> return ERR_PTR(-EINVAL);
> + sqpn = get_sqp_num(to_mdev(pd->device), init_attr);
> +
> + if (sqpn < 0)
> + return ERR_PTR(sqpn);
>
> err = create_qp_common(to_mdev(pd->device), pd, init_attr,
> udata,
> - get_sqp_num(to_mdev(pd->device), init_attr),
> + sqpn,
> &qp, gfp);
> if (err)
> return ERR_PTR(err);
>
> qp->port = init_attr->port_num;
> - qp->ibqp.qp_num = init_attr->qp_type == IB_QPT_SMI ? 0 : 1;
> -
> + qp->ibqp.qp_num = init_attr->qp_type == IB_QPT_SMI ? 0 :
> + init_attr->create_flags & MLX4_IB_QP_CREATE_ROCE_V2_GSI
> ? sqpn : 1;
> break;
> }
> default:
> @@ -1140,7 +1167,41 @@ struct ib_qp *mlx4_ib_create_qp(struct ib_pd *pd,
> return &qp->ibqp;
> }
>
> -int mlx4_ib_destroy_qp(struct ib_qp *qp)
> +struct ib_qp *mlx4_ib_create_qp(struct ib_pd *pd,
> + struct ib_qp_init_attr *init_attr,
> + struct ib_udata *udata) {
> + struct ib_qp *ibqp;
> + struct mlx4_ib_dev *dev = to_mdev(pd->device);
> +
> + ibqp = _mlx4_ib_create_qp(pd, init_attr, udata);
> +
> + if (!IS_ERR_OR_NULL(ibqp) &&
> + (init_attr->qp_type == IB_QPT_GSI) &&
> + !(init_attr->create_flags & MLX4_IB_QP_CREATE_ROCE_V2_GSI)) {
> + struct mlx4_ib_sqp *sqp = to_msqp((to_mqp(ibqp)));
> + int is_eth = rdma_port_get_link_layer(pd->device, init_attr-
> >port_num) ==
> + IB_LINK_LAYER_ETHERNET;
> +
> + if (is_eth &&
> + dev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_ROCE_V1_V2) {
> + init_attr->create_flags |=
> MLX4_IB_QP_CREATE_ROCE_V2_GSI;
> + sqp->roce_v2_gsi = ib_create_qp(pd, init_attr);
> +
> + if (IS_ERR_OR_NULL(sqp->roce_v2_gsi)) {
> + pr_err("Failed to create GSI QP for RoCEv2
> (%ld)\n", PTR_ERR(sqp->roce_v2_gsi));
> + sqp->roce_v2_gsi = NULL;
> + } else {
> + sqp = to_msqp(to_mqp(sqp->roce_v2_gsi));
> + sqp->qp.flags |= MLX4_IB_ROCE_V2_GSI_QP;
> + }
> +
> + init_attr->create_flags &=
> ~MLX4_IB_QP_CREATE_ROCE_V2_GSI;
> + }
> + }
> + return ibqp;
> +}
> +
> +static int _mlx4_ib_destroy_qp(struct ib_qp *qp)
> {
> struct mlx4_ib_dev *dev = to_mdev(qp->device);
> struct mlx4_ib_qp *mqp = to_mqp(qp);
> @@ -1166,6 +1227,20 @@ int mlx4_ib_destroy_qp(struct ib_qp *qp)
> return 0;
> }
>
> +int mlx4_ib_destroy_qp(struct ib_qp *qp)
> +{
> + struct mlx4_ib_qp *mqp = to_mqp(qp);
> +
> + if (mqp->mlx4_ib_qp_type == MLX4_IB_QPT_GSI) {
> + struct mlx4_ib_sqp *sqp = to_msqp(mqp);
> +
> + if (sqp->roce_v2_gsi)
> + ib_destroy_qp(sqp->roce_v2_gsi);
> + }
> +
> + return _mlx4_ib_destroy_qp(qp);
> +}
> +
> static int to_mlx4_st(struct mlx4_ib_dev *dev, enum mlx4_ib_qp_type
> type)
> {
> switch (type) {
> @@ -1539,6 +1614,14 @@ static int __mlx4_ib_modify_qp(struct ib_qp
> *ibqp,
> mlx4_ib_steer_qp_reg(dev, qp, 1);
> steer_qp = 1;
> }
> +
> + if (ibqp->qp_type == IB_QPT_GSI) {
> + enum ib_gid_type gid_type = qp->flags &
> MLX4_IB_ROCE_V2_GSI_QP ?
> + IB_GID_TYPE_ROCE_V2 : IB_GID_TYPE_IB;
> + u8 qpc_roce_mode = gid_type_to_qpc(gid_type);
> +
> + context->rlkey_roce_mode |= (qpc_roce_mode << 6);
> + }
> }
>
> if (attr_mask & IB_QP_PKEY_INDEX) {
> @@ -1936,8 +2019,8 @@ out:
> return err;
> }
>
> -int mlx4_ib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
> - int attr_mask, struct ib_udata *udata)
> +static int _mlx4_ib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr
> *attr,
> + int attr_mask, struct ib_udata *udata)
> {
> struct mlx4_ib_dev *dev = to_mdev(ibqp->device);
> struct mlx4_ib_qp *qp = to_mqp(ibqp);
> @@ -2040,6 +2123,25 @@ out:
> return err;
> }
>
> +int mlx4_ib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
> + int attr_mask, struct ib_udata *udata)
> +{
> + struct mlx4_ib_qp *mqp = to_mqp(ibqp);
> + int ret;
> +
> + ret = _mlx4_ib_modify_qp(ibqp, attr, attr_mask, udata);
> +
> + if (mqp->mlx4_ib_qp_type == MLX4_IB_QPT_GSI) {

You are missing a check here for _mlx4_ib_modify_qp failing. In such case, you should bail out immediately, as modifying the roce_v2 QP will fail as well.

> + struct mlx4_ib_sqp *sqp = to_msqp(mqp);
> +
> + if (sqp->roce_v2_gsi)
> + ret = ib_modify_qp(sqp->roce_v2_gsi, attr, attr_mask);
> + if (ret)
> + pr_err("Failed to modify GSI QP for RoCEv2 (%d)\n",
> ret);
> + }
> + return ret;
> +}
> +
> static int vf_get_qp0_qkey(struct mlx4_dev *dev, int qpn, u32 *qkey)
> {
> int i;
> @@ -2702,6 +2804,22 @@ int mlx4_ib_post_send(struct ib_qp *ibqp, struct
> ib_send_wr *wr,
> __be32 blh;
> int i;
>
> + if (qp->mlx4_ib_qp_type == MLX4_IB_QPT_GSI) {
> + struct mlx4_ib_sqp *sqp = to_msqp(qp);
> +
> + if (sqp->roce_v2_gsi) {
> + struct mlx4_ib_ah *ah = to_mah(wr->wr.ud.ah);
> + struct ib_gid_attr gid_attr;
> + union ib_gid gid;
> +
> + if (!ib_get_cached_gid(ibqp->device,
> + be32_to_cpu(ah->av.ib.port_pd) >> 24,

This is the 4th time, in this file, where you are doing a be32_to_cpu + shift just to get the port number from the AV. Consider either adding it as an explicit field or writing a small helper for doing this (mlx4_ib_ah_to_port). Also, many of the other uses are in the same function, consider keeping a cached copy of the value.

> + ah->av.ib.gid_index, &gid, &gid_attr))
> + qp = (gid_attr.gid_type == IB_GID_TYPE_ROCE_V2) ?
> + to_mqp(sqp->roce_v2_gsi) : qp;

What happens if sqp->roce_v2_gsi is NULL? Can it happen? If so, wouldn't the to_mqp code cause really weird results?

> + }
> + }
> +
> spin_lock_irqsave(&qp->sq.lock, flags);
>
> ind = qp->sq_next_wqe;
> --
> 1.7.1
>
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