Re: [PATCH] RDMA/rxe: Don't set BTH_ACK_MASK for UC or UD QPs

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2024/6/24 10:03, Honggang LI 写道:
> BTH_ACK_MASK bit is used to indicate that an acknowledge
> (for this packet) should be scheduled by the responder.
> Both UC and UD QPs are unacknowledged, so don't set
> BTH_ACK_MASK for UC or UD QPs.

 From IBTA
"
o9-30: If a TCA responder implements Reliable Connection service, or if
a CA responder implements Reliable Datagram or XRC service, the 
responder shall behave as follows. A responder shall acknowledge each 
request packet received. A responder shall generate an explicit response
for each RDMA READ request received. A responder shall generate an
explicit response for each ATOMIC Request received. A responder shall
generate response packets in the PSN order in which the original request
packets were received, including RDMA READ responses.
"

This ack_req should be based on "Reliable Connection service".
As such, I am fine with this commit.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Thanks,
Zhu Yanjun

> 
> Fixes: 8700e3e7c485 ("Soft RoCE driver")
> Signed-off-by: Honggang LI <honggangli@163.com>
> ---
>   drivers/infiniband/sw/rxe/rxe_req.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
> index cd14c4c2dff9..ffd7ed712a02 100644
> --- a/drivers/infiniband/sw/rxe/rxe_req.c
> +++ b/drivers/infiniband/sw/rxe/rxe_req.c
> @@ -445,8 +445,12 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
>   	qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
>   					 qp->attr.dest_qp_num;
>   
> -	ack_req = ((pkt->mask & RXE_END_MASK) ||
> -		(qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
> +	if (qp_type(qp) == IB_QPT_UD || qp_type(qp) == IB_QPT_UC)
> +		ack_req = 0;
> +	else {
> +		ack_req = ((pkt->mask & RXE_END_MASK) ||
> +			(qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
> +	}
>   	if (ack_req)
>   		qp->req.noack_pkts = 0;
>