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Date:   Wed, 15 Jan 2020 14:27:21 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     rao Shoaib <rao.shoaib@oracle.com>
Cc:     linux-rdma@vger.kernel.org, monis@mellanox.com,
        dledford@redhat.com, sean.hefty@intel.com,
        hal.rosenstock@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] SGE buffer and max_inline data must have same size
Message-ID: <20200115182721.GE25201@ziepe.ca>
References: <1578962480-17814-1-git-send-email-rao.shoaib@oracle.com>
 <1578962480-17814-3-git-send-email-rao.shoaib@oracle.com>
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On Mon, Jan 13, 2020 at 04:41:20PM -0800, rao Shoaib wrote:
> From: Rao Shoaib <rao.shoaib@oracle.com>
> 
> SGE buffer size and max_inline data should be same. Maximum of the
> two values requested is used.
> 
> Signed-off-by: Rao Shoaib <rao.shoaib@oracle.com>
>  drivers/infiniband/sw/rxe/rxe_qp.c | 23 +++++++++++------------
>  1 file changed, 11 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
> index aeea994..41c669c 100644
> +++ b/drivers/infiniband/sw/rxe/rxe_qp.c
> @@ -235,18 +235,17 @@ static int rxe_qp_init_req(struct rxe_dev *rxe, struct rxe_qp *qp,
>  		return err;
>  	qp->sk->sk->sk_user_data = qp;
>  
> -	qp->sq.max_wr		= init->cap.max_send_wr;
> -	qp->sq.max_sge		= init->cap.max_send_sge;
> -	qp->sq.max_inline	= init->cap.max_inline_data;
> -
> -	wqe_size = max_t(int, sizeof(struct rxe_send_wqe) +
> -			 qp->sq.max_sge * sizeof(struct ib_sge),
> -			 sizeof(struct rxe_send_wqe) +
> -			 qp->sq.max_inline);
> -
> -	qp->sq.queue = rxe_queue_init(rxe,
> -				      &qp->sq.max_wr,
> -				      wqe_size);
> +	wqe_size = max_t(int, init->cap.max_send_sge * sizeof(struct ib_sge),
> +			 init->cap.max_inline_data);
> +	qp->sq.max_sge = wqe_size/sizeof(struct ib_sge);
> +	qp->sq.max_inline = wqe_size;
> +
> +	wqe_size += sizeof(struct rxe_send_wqe);

Where does this limit the user's request to RXE_MAX_WQE_SIZE ?

I seem to recall the if the requested max can't be satisified then
that is an EINVAL?

And the init->cap should be updated with the actual allocation.

So more like:

        if (init->cap.max_send_sge > RXE_MAX_SGE ||
           init->cap.max_inline_data > RXE_MAX_INLINE)
            return -EINVAL;

	wqe_size = max_t(int, init->cap.max_sge * sizeof(struct ib_sge),
			 init->cap.max_inline_data)
                   sizeof(struct rxe_send_wqe);
	qp->sq.max_sge = init->cap.max_send_sge = wqe_size/sizeof(struct ib_sge);
	qp->sq.max_inline = init->cap.max_inline_data = wqe_size;
	wqe_size += sizeof(struct rxe_send_wqe);

Jason