> -----Original Message----- > From: Anand Ashok Khoje <anand.a.khoje@xxxxxxxxxx> > Sent: Friday, 13 May 2022 06:10 > To: Linux RDMA <linux-rdma@xxxxxxxxxxxxxxx>; Jason Gunthorpe > <jgg@xxxxxxxx>; Doug Ledford <dledford@xxxxxxxxxx> > Cc: Rama Nichanamatlu <rama.nichanamatlu@xxxxxxxxxx>; Manjunath Patil > <manjunath.b.patil@xxxxxxxxxx> > Subject: [EXTERNAL] Re: [RFC] Adding private data and private data len > as argument to rdma_disconnect() > > Hi, > > > A kind reminder. > > > Thanks, > > Anand > > On 5/5/22 15:32, Anand Ashok Khoje wrote: > > Hi, > > > > I just wanted to float an idea for an enhancement and get opinions. > > > > There is a provision in ib_cm layer API ib_send_cm_dreq() to send a > > private_data along with the DREQ. > > This private_data is helpful in situations where the receiver of DREQ > > may want > > to understand the reason for the DREQ and do some action on the basis > > of that > > reason. > > We have come across issues where it was critical for the RDS code to > > understand > > the reason behind a DREQ and recover/tweak some parameters. > > > > Now, rdma_cm layer has a wrapper around ib_send_cm_dreq() i.e > > rdma_disconnect(). > > rdma_disconnect() is used by the consumers of rdma_cm. > > rdma_disconnect() does > > not have an argument that accepts private data. Due to this, consumers > > are not > > able to use this feature. > > > > In case if we add the arguments private_data and private_data_length > to > > rds_disconnect(), the only challenge would be to add those to the > callers > > of it (NULL and 0). > > > > Please let me know your thoughts on this. > > > > Thanks > > Anand > > Not all providers support the transfer of private data in control messages after connection establishment - rdma_reject()/rdma_accept() being the last opportunity to send private data in connections lifetime for e.g. iWarp connections. Maybe that is why it is not exposed at the disconnect API call? Would RoCE support it? I think you also ask for extending the CM event infrastructure to carry private data in DISCONNECTED events? Thanks, Bernard
