Re: [PATCH for-next v5 5/6] RDMA/rxe: Lookup kernel AH from ah index in UD WQEs

[Zhu Yanjun <zyjzyj2000@gmail.com>]

On Wed, Oct 6, 2021 at 9:58 AM Bob Pearson <rpearsonhpe@gmail.com> wrote:
>
> Add code to rxe_get_av in rxe_av.c to use the AH index in UD send WQEs
> to lookup the kernel AH. For old user providers continue to use the AV
> passed in WQEs. Move setting pkt->rxe to before the call to rxe_get_av()
> to get access to the AH pool.
>
> Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
> ---
>  drivers/infiniband/sw/rxe/rxe_av.c  | 20 +++++++++++++++++++-
>  drivers/infiniband/sw/rxe/rxe_req.c |  8 +++++---
>  2 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_av.c b/drivers/infiniband/sw/rxe/rxe_av.c
> index 85580ea5eed0..38c7b6fb39d7 100644
> --- a/drivers/infiniband/sw/rxe/rxe_av.c
> +++ b/drivers/infiniband/sw/rxe/rxe_av.c
> @@ -101,11 +101,29 @@ void rxe_av_fill_ip_info(struct rxe_av *av, struct rdma_ah_attr *attr)
>
>  struct rxe_av *rxe_get_av(struct rxe_pkt_info *pkt)
>  {
> +       struct rxe_ah *ah;
> +       u32 ah_num;
> +
>         if (!pkt || !pkt->qp)
>                 return NULL;
>
>         if (qp_type(pkt->qp) == IB_QPT_RC || qp_type(pkt->qp) == IB_QPT_UC)
>                 return &pkt->qp->pri_av;
>
> -       return (pkt->wqe) ? &pkt->wqe->wr.wr.ud.av : NULL;
> +       if (!pkt->wqe)
> +               return NULL;
> +
> +       ah_num = pkt->wqe->wr.wr.ud.ah_num;
> +       if (ah_num) {
> +               /* only new user provider or kernel client */

struct rxe_ah *ah;
ah is only used in this snippet. Is it better to move to here?
It is only a trivial problem.

Zhu Yanjun
> +               ah = rxe_pool_get_index(&pkt->rxe->ah_pool, ah_num);
> +               if (!ah || ah->ah_num != ah_num || rxe_ah_pd(ah) != pkt->qp->pd) {
> +                       pr_warn("Unable to find AH matching ah_num\n");
> +                       return NULL;
> +               }
> +               return &ah->av;
> +       }
> +
> +       /* only old user provider for UD sends*/
> +       return &pkt->wqe->wr.wr.ud.av;
>  }
> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
> index fe275fcaffbd..0c9d2af15f3d 100644
> --- a/drivers/infiniband/sw/rxe/rxe_req.c
> +++ b/drivers/infiniband/sw/rxe/rxe_req.c
> @@ -379,9 +379,8 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
>         /* length from start of bth to end of icrc */
>         paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;
>
> -       /* pkt->hdr, rxe, port_num and mask are initialized in ifc
> -        * layer
> -        */
> +       /* pkt->hdr, port_num and mask are initialized in ifc layer */
> +       pkt->rxe        = rxe;
>         pkt->opcode     = opcode;
>         pkt->qp         = qp;
>         pkt->psn        = qp->req.psn;
> @@ -391,6 +390,9 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
>
>         /* init skb */
>         av = rxe_get_av(pkt);
> +       if (!av)
> +               return NULL;
> +
>         skb = rxe_init_packet(rxe, av, paylen, pkt);
>         if (unlikely(!skb))
>                 return NULL;
> --
> 2.30.2
>