Re: [PATCH 2/2] RDMA/rxe: Handle remote errors in the midst of a Read reply sequence

[Li Zhijian <lizhijian@fujitsu.com>]

On 13/10/2022 09:47, Daisuke Matsuda wrote:
> Requesting nodes do not handle a reported error correctly if it is
> generated in the middle of multi-packet Read responses, and the node tries
> to resend the request endlessly. Let completer terminate the connection in
> that case.
>
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> ---
> FOR REVIEWERS:
>    I referred to IB Specification Vol 1-Revision-1.5 to make this patch.
>    Please see Ch.9.9.2.2, Ch.9.9.2.4.2 and Table 59.
>
>   drivers/infiniband/sw/rxe/rxe_comp.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c
> index fb0c008af78c..c9170dd99f3a 100644
> --- a/drivers/infiniband/sw/rxe/rxe_comp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_comp.c
> @@ -200,6 +200,10 @@ static inline enum comp_state check_psn(struct rxe_qp *qp,
>   		 */
>   		if (pkt->psn == wqe->last_psn)
>   			return COMPST_COMP_ACK;
> +		else if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE &&
> +			 (qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST ||
> +			  qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE))
When IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST or IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE will be assigned to qp->comp.opcode ?
I wonder if "(pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE) "  is enough ?

Thanks
Zhijian


> +			return COMPST_CHECK_ACK;
>   		else
>   			return COMPST_DONE;
>   	} else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
> @@ -228,6 +232,10 @@ static inline enum comp_state check_ack(struct rxe_qp *qp,
>   
>   	case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
>   	case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
> +		/* Check NAK code to handle a remote error */
> +		if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE)
> +			break;
> +
>   		if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
>   		    pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
>   			/* read retries of partial data may restart from