Re: [PATCH for-next] IB/cma: Introduce rdma_set_min_rnr_timer()

Jason Gunthorpe
2021-03-31T17:36:20Z

On Wed, Mar 31, 2021 at 05:09:27PM +0000, Parav Pandit wrote:
>
>
> > From: Haakon Bugge <haakon.bugge@oracle.com>
> > Sent: Wednesday, March 31, 2021 8:20 PM
> >
> > > On 31 Mar 2021, at 15:35, Jason Gunthorpe <jgg@nvidia.com> wrote:
> > >
> > > On Wed, Mar 31, 2021 at 01:34:06PM +0000, Haakon Bugge wrote:
> > >
> > >>> Actually I bet you could do this same thing entirely in userspace by
> > >>> adjusting rdma_init_qp_attr() to copy the data that would be stored
> > >>> in the cm_id.. ??
> > >>
> > >> This will definitely not solve the issue for kernel ULP, e.g., RDS.
> > >
> > > Sure, that makes sense to have some rdmacm api in-kernel only
> >
> > Let me send a v2 doing only that.
> >
> > >> Further, why do we have rdma_set_option() with option
> > RDMA_OPTION_ID_ACK_TIMEOUT ?
> > >
> > > It may have been a mistake to do it like that
> >
> Timeout value goes in the CM request message so setting it through
> the cm_id object was likely correct. This reflects into cm msg as
> well as in the QP of the cm_id.

Ah, yes if it goes in the wire in a CM message it has to go to the
kernel.

Jason