All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michal Kalderon <mkalderon@marvell.com>
To: Jason Gunthorpe <jgg@mellanox.com>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	Leon Romanovsky <leon@kernel.org>,
	Kamal Heib <kamalheib1@gmail.com>
Subject: RE: [EXT] Re: rdma-core new/old compatability
Date: Tue, 3 Mar 2020 14:42:15 +0000	[thread overview]
Message-ID: <MN2PR18MB318285FCB1291FAEF1C406B6A1E40@MN2PR18MB3182.namprd18.prod.outlook.com> (raw)
In-Reply-To: <20200227135529.GH26318@mellanox.com>

> From: Jason Gunthorpe <jgg@mellanox.com>
> Sent: Thursday, February 27, 2020 3:55 PM
> 
> ----------------------------------------------------------------------
> On Thu, Feb 27, 2020 at 01:11:13PM +0000, Michal Kalderon wrote:
> > Hi Kamal, Jason,
> >
> > Running a version of ibv_devinfo compiled against an old rdma-core
> > (ibv_devinfo from libibverbs-utils-16.2-3-fc28.x86_64 ) failed to run with
> rdma-core release 28.0 for qedr.
> >
> > The patch that caused this is commit c2841076
> > https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__github.com_linux-
> > 2Drdma_rdma-
> 2Dcore_commit_c28410765bdfe5cbed3cb2cdb1584eac3941469c-23d
> > iff-
> 2D8da8bc8b2790169de557d5dee83a278e&d=DwIBAg&c=nKjWec2b6R0mOyP
> az7xt
> > fQ&r=5_8rRZTDuAS-6X-cGRU9Fo4yjCnkS1t7T3-
> gjL4FQng&m=8roKblaWiyWNhzEkhi8
> > gJYJs1ZHqJ0lqf_0OMh3fHBM&s=x5-
> fhg21NUEcxJ2zxM135ujpopHtey138zz9waiflS8
> > &e=
> > c28410765bdf
> >
> > libibverbs: Fix incorrect return code ...
> >
> > The proper return code is EOPNOTSUPP when an operation is not
> supported.
> >
> > Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
> >
> > The reason it failed is because qedr doesn't have a query_device_ex
> > callback, so vctx->query_device_ex returns EOPNOTSUPP, and old
> > libibverbs Compares the return code to ENOSYS
> 
> This is surprising and unfortunate
> 
> > I think applications compiled against old rdma-core should continue to
> > run on new ones as well.  Can this commit be reverted?
> 
> I would prefer to only revert the little bit that might be needed for
> compatability.
> 
> Perhaps we should change the dummy function to implement
> query_device_ex for all providers? Zeroing the extended data should be
> sufficient I think.
I've submitted pull-request #713 that implements the dummy function.

Thanks,
Michal

> 
> Unfortunately we are changing return codes inadvertantly quite often, and
> the providers tend to use different codes.
> 
> Jason

      reply	other threads:[~2020-03-03 14:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-27 13:11 rdma-core new/old compatability Michal Kalderon
2020-02-27 13:55 ` Jason Gunthorpe
2020-03-03 14:42   ` Michal Kalderon [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=MN2PR18MB318285FCB1291FAEF1C406B6A1E40@MN2PR18MB3182.namprd18.prod.outlook.com \
    --to=mkalderon@marvell.com \
    --cc=jgg@mellanox.com \
    --cc=kamalheib1@gmail.com \
    --cc=leon@kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.