On Monday, August 29, 2022 4:36 PM, Li Zhijian wrote:
> On 29/08/2022 13:44, Daisuke Matsuda wrote:
> > An incoming Read request causes multiple Read responses. If a user MR to
> > copy data from is unavailable or responder cannot send a reply, then the
> > error messages can be printed for each response attempt, resulting in
> > message overflow.
> >
> > Signed-off-by: Daisuke Matsuda <matsuda-daisuke@xxxxxxxxxxx>
> > ---
> > drivers/infiniband/sw/rxe/rxe_resp.c | 6 +-----
> > 1 file changed, 1 insertion(+), 5 deletions(-)
> >
> > diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> > index b36ec5c4d5e0..4b3e8aec2fb8 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> > @@ -811,8 +811,6 @@ static enum resp_states read_reply(struct rxe_qp *qp,
> >
> > err = rxe_mr_copy(mr, res->read.va, payload_addr(&ack_pkt),
> > payload, RXE_FROM_MR_OBJ);
> > - if (err)
> > - pr_err("Failed copying memory\n");
> Not relate to this patch.
> I'm wondering why this err is ignored, rxe_mr_copy() does the real execution or rxe_mr_copy() would never fail ?
> IMO, when err happens, responder shall notify the request anyhow.
Practically, I have never seen rxe_mr_copy() failed before,
but I agree the implementation may be incorrect as you mentioned.
As far as I tested, responder replied with the requested amount of payloads
even when rxe_mr_copy() is modified to fail. In this case,
requester may mistakenly believe that they get data correctly.
For more details, see IB Specification Vol 1-Revision-1.5 Ch.9.7.5.1.3 (page.334).
Daisuke Matsuda
>
> Thanks
> Zhijian
>
> > if (mr)
> > rxe_put(mr);
> >
> > @@ -823,10 +821,8 @@ static enum resp_states read_reply(struct rxe_qp *qp,
> > }
> >
> > err = rxe_xmit_packet(qp, &ack_pkt, skb);
> > - if (err) {
> > - pr_err("Failed sending RDMA reply.\n");
> > + if (err)
> > return RESPST_ERR_RNR;
> > - }
> >
> > res->read.va += payload;
> > res->read.resid -= payload;
