Re: [PATCH v4 7/9] IB/core: generic RDMA READ/WRITE API

[Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>]

On 03/10/2016 08:21 AM, Christoph Hellwig wrote:
> I see the use case for enabling MRs for debugging, but I still don't
> think the ULP is the right place.  I also don't see where you
> cna do this currently: for srpt, the only driver converted in this
> series there is no support for registrations at all currently,
> and with the the series you can force it to register with a one
> line code change in rdma_rw_use_mr.  For iSERt, which I plan to
> convert for 4.7 (and which has some WIP code in git) MR support
> exists, but is only enabled if the device supports the vendor
> specific signature handover extension (aka if running on mlx5 hardware).
> With the future conversion you'll still have a simply compile time
> switch to always enabled it, and I'd be fine with adding a module
> parameter to force it as well.

Hello Christoph,

The above is fine with me. But when I ran a test with rdma_rw_use_mr() 
changed into "return true" the following error messages appeared in the 
kernel log:

[  364.460709] ib_srpt 0x1: parsing SRP descriptor table failed.
[  383.604809] ib_srpt 0x0: parsing SRP descriptor table failed.
[  383.605627] ib_srpt 0x2: parsing SRP descriptor table failed.
[  386.702905] ib_srpt 0x3: parsing SRP descriptor table failed.
[  386.703092] ib_srpt 0x4: parsing SRP descriptor table failed.
[  386.703242] ib_srpt 0x5: parsing SRP descriptor table failed.
[  386.703411] ib_srpt 0x6: parsing SRP descriptor table failed.

Is this expected? I ran this test on a server equipped with two mlx4 
HCAs with latest firmware (2.36.5000). I installed git commit 
c4c65482b56a433a82bc5b63db8ba125727e9f80 of the rdma-rw-api merged with 
v4.5-rc7. Initiator and target drivers were running on the same server 
and were communicating with each other via loopback. Before I modified 
rdma_rw_use_mr() the same test passed on the same setup.

Do you perhaps want me to look further into this?

Thanks,

Bart.
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