[ofa-general] Re: NOSRQ misc patch [PATCH V1]

[Michael S. Tsirkin]

> Quoting Pradeep Satyanarayana <pradeeps at linux.vnet.ibm.com>:
> Subject: Re: NOSRQ misc patch [PATCH V1]
> 
> Michael S. Tsirkin wrote:
> >> @@ -1168,9 +1170,9 @@ static struct ib_qp *ipoib_cm_create_tx_
> >>  	attr.recv_cq = priv->cq;
> >>  	attr.srq = priv->cm.srq;
> >>  	attr.cap.max_send_wr = ipoib_sendq_size;
> >> -	attr.cap.max_recv_wr = 1;
> >> +	attr.cap.max_recv_wr = 0;
> >>  	attr.cap.max_send_sge = 1;
> >> -	attr.cap.max_recv_sge = 1;
> >> +	attr.cap.max_recv_sge = 0;
> >>  	attr.sq_sig_type = IB_SIGNAL_ALL_WR;
> >>  	attr.qp_type = IB_QPT_RC;
> >>  	attr.send_cq = cq;
> > 
> > I don't see how does this fix things.
> > This line 
> >>  	attr.srq = priv->cm.srq;
> > connected the TX QP to SRQ, making it possible to get packets on this QP.
> > But if cm.srq is NULL, and a remote sends a packet on this connection,
> > the connection will get closed. Which is a quality of implementation issue.
> > 
> When the QP numbers are exchanged correctly, then it should not receive
> a packet on this QP in the first place.

Re-read the RFC. It is perfectly legal to reuse a passive QP for transmitting
packets. We don't do this currently but we might in the future.

> That is an error case and so should
> be a rare event. Assuming that still happens, that should be setup again 
> because it is an RC connection.

Won't it closed immediately again once remote tries to use it?

-- 
MST