freebsd stable - Feb 2018 - [HEADS UP] - OFED/RDMA stack update

+freebsd-arch@

Hi Meny,

Can you please post the KPI/KBI analysis that you generated to some
public location and provide a link here?  A straight MFC would be a
major break of KPI/KBI in -STABLE and the options we're looking at are:

a) Ignore the breakage and let downstream consumers deal with the
fallout.  This obviously isn't ideal in a -STABLE branch.

b) Provide compat shims to at least preserve the KPI.  One challenge is
that the changes include functions with the same name but different
signature/behavior.  See, for example, ib_create_cq in Meny's list once
he publishes it.

c) Have two versions of the OFED interfaces in 11-STABLE and not break
existing downstream consumers at all.

I've reached out to users that I know of and know will be affected.
If you use OFED and FreeBSD 11 this would be a good time to weigh
in with your thoughts, ideas, concerns etc..

Regards,
Navdeep

On Mon, 2018-02-26 at 14:49 +0000, Meny Yossefi wrote:
> Hi, 
> 
> We are currently working on MFC'ing the OFED/RDMA stack update
> mentioned below to FreeBSD11-STABLE.
> 
> We already have working version in
'projects/bsd_rdma_4_9_stable_11'
> (pending iWARP updates) and currently working on ULP integration.
> 
> Again, as always, for any concern/comments you might have, please
> don't hesitate contacting us.
> 
> freebsd-drivers at mellanox.com
> 
> 
> Regards, 
> 
> Meny Yossefi, 
> Mellanox technologies
> 
> 
> -----Original Message-----
> From: Meny Yossefi 
> Sent: Monday, November 13, 2017 11:09 AM
> To: 'freebsd-infiniband at freebsd.org' <freebsd-infiniband at
freebsd.org>;
> 'freebsd-current at freebsd.org' <freebsd-current at
freebsd.org>
> Cc: freebsd-drivers <freebsd-drivers at mellanox.com>
> Subject: [HEADS UP] - OFED/RDMA stack update 
> 
> Hi, 
> 
> This is to inform you that by end of this week we plan to merge the
> OFED/RDMA stack update from the project - 'bsd_rdma_4_9' into 12-
> CURRENT.
> The update aligns the OFED common code and RDMA vendor drivers with
> Linux v4.9.
> 
> We are still working on final modifications and build testing it prior
> to submission.
> 
> 
> For any concern/comments you might have, please don't hesitate
> contacting us.
> 
> freebsd-drivers at mellanox.com
> 
> 
> Regards, 
> 
> Meny Yossefi, 
> Mellanox technologies
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On Mon, Feb 26, 2018 at 02:21:39PM -0800, Navdeep Parhar
wrote:
> +freebsd-arch@
> 
> Hi Meny,
> 
> Can you please post the KPI/KBI analysis that you generated to some
> public location and provide a link here?  A straight MFC would be a
> major break of KPI/KBI in -STABLE and the options we're looking at are:
I put the report at
https://kib.kiev.ua/kib/ibcore_11_to_11_merged_compat_report.html
> 
> a) Ignore the breakage and let downstream consumers deal with the
> fallout.  This obviously isn't ideal in a -STABLE branch.
> 
> b) Provide compat shims to at least preserve the KPI.  One challenge is
> that the changes include functions with the same name but different
> signature/behavior.  See, for example, ib_create_cq in Meny's list once
> he publishes it.
Project did handled similar issues already.  One of the approaches is to
renname the ib_create_cq with the new signature to ib_create_cq_n12 and
check for (e.g.) _WANT_NEW_OFED symbol and to select one or another:
#ifdef _WANT_NEW_OFED
#define ib_create_cq(new args there) ib_create_cq_n21(new args there)
#else
#define ib_create_cq (ib_create_cq)
#endif

Then ULP that wants new KPI defines _WANT_NEW_OFED.
> 
> c) Have two versions of the OFED interfaces in 11-STABLE and not break
> existing downstream consumers at all.
It is possible to make them loadable simultaneously as modules, but it
is quite confusing to users, because Mellanox clearly wants mlx5_ib and
mlx4_ib to work only with new OFED, while cxgbe would use old OFED ?

Also, either we would need to mess with the ibcore.ko module name, or
with version.  I am not sure that our module handling is robust enough
to make the version trick possible.
> 
> I've reached out to users that I know of and know will be affected.
> If you use OFED and FreeBSD 11 this would be a good time to weigh
> in with your thoughts, ideas, concerns etc..