Subject: Re: [PATCH rdma-next v2 7/7] RDMA/cma: Provide ECE reject reason

From: Jason Gunthorpe <[email-masked]>
Date: Mon, 25 May 2020 15:36:47 -0300

On Mon, May 25, 2020 at 09:22:42PM +0300, Leon Romanovsky wrote:
> On Mon, May 25, 2020 at 03:14:17PM -0300, Jason Gunthorpe wrote:
> > On Mon, Apr 13, 2020 at 05:15:38PM +0300, Leon Romanovsky wrote:
> > > @@ -4223,7 +4223,7 @@ int rdma_notify(struct rdma_cm_id *id, enum ib_event_type event)
> > >  EXPORT_SYMBOL(rdma_notify);
> > >
> > >  int rdma_reject(struct rdma_cm_id *id, const void *private_data,
> > > -		u8 private_data_len)
> > > +		u8 private_data_len, enum rdma_ucm_reject_reason reason)
> > >  {
> > >  	struct rdma_id_private *id_priv;
> > >  	int ret;
> > > @@ -4237,10 +4237,12 @@ int rdma_reject(struct rdma_cm_id *id, const void *private_data,
> > >  			ret = cma_send_sidr_rep(id_priv, IB_SIDR_REJECT, 0,
> > >  						private_data, private_data_len);
> > >  		} else {
> > > +			enum ib_cm_rej_reason r =
> > > +				(reason) ?: IB_CM_REJ_CONSUMER_DEFINED;
> > > +
> > >  			trace_cm_send_rej(id_priv);
> > > -			ret = ib_send_cm_rej(id_priv->cm_id.ib,
> > > -					     IB_CM_REJ_CONSUMER_DEFINED, NULL,
> > > -					     0, private_data, private_data_len);
> > > +			ret = ib_send_cm_rej(id_priv->cm_id.ib, r, NULL, 0,
> > > +					     private_data, private_data_len);
> > >  		}
> > >  	} else if (rdma_cap_iw_cm(id->device, id->port_num)) {
> > >  		ret = iw_cm_reject(id_priv->cm_id.iw,
> > > diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
> > > index d41598954cc4..99482dc5934b 100644
> > > +++ b/drivers/infiniband/core/ucma.c
> > > @@ -1178,12 +1178,17 @@ static ssize_t ucma_reject(struct ucma_file *file, const char __user *inbuf,
> > >  	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
> > >  		return -EFAULT;
> > >
> > > +	if (cmd.reason &&
> > > +	    cmd.reason != RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED)
> > > +		return -EINVAL;
> >
> > It would be clearer to set cmd.reason to IB_CM_REJ_CONSUMER_DEFINED at
> > this point..
> >
> > if (!cmd.reason)
> >    cmd.reason = IB_CM_REJ_CONSUMER_DEFINED
> >
> > if (cmd.reason != IB_CM_REJ_CONSUMER_DEFINED && cmd.reason !=
> >     RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED)
> >    return -EINVAL
> >
> > Esaier to follow and no reason userspace shouldn't be able to
> > explicitly specifiy the reason's that it is allowed to use.
> >
> >
> > > index 8d961d8b7cdb..f8781b132f62 100644
> > > +++ b/include/rdma/rdma_cm.h
> > > @@ -324,11 +324,12 @@ int __rdma_accept_ece(struct rdma_cm_id *id, struct rdma_conn_param *conn_param,
> > >   */
> > >  int rdma_notify(struct rdma_cm_id *id, enum ib_event_type event);
> > >
> > > +
> > >  /**
> >
> > Extra hunk?
> >
> > >   * rdma_reject - Called to reject a connection request or response.
> > >   */
> > >  int rdma_reject(struct rdma_cm_id *id, const void *private_data,
> > > -		u8 private_data_len);
> > > +		u8 private_data_len, enum rdma_ucm_reject_reason reason);
> > >
> > >  /**
> > >   * rdma_disconnect - This function disconnects the associated QP and
> > > diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
> > > index c4ca1412bcf9..e545f2de1e13 100644
> > > +++ b/include/uapi/rdma/rdma_user_cm.h
> > > @@ -78,6 +78,10 @@ enum rdma_ucm_port_space {
> > >  	RDMA_PS_UDP   = 0x0111,
> > >  };
> > >
> > > +enum rdma_ucm_reject_reason {
> > > +	RDMA_USER_CM_REJ_VENDOR_OPTION_NOT_SUPPORTED = 35
> > > +};
> >
> > not sure we need ABI defines for IBTA constants?
> 
> Do you want to give an option to write any number?
> Right now, I'm enforcing only allowed by IBTA reason
> and which is used in user space.

no, just the allowed numbers, just wondering if we need constants for
fixed IBTA values .. 

Jason