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From: Jason Gunthorpe <jgg@mellanox.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: davem@davemloft.net, dledford@redhat.com,
	Sindhu Devale <sindhu.devale@intel.com>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com,
	Shiraz Saleem <shiraz.saleem@intel.com>
Subject: Re: [net-next] i40iw/i40e: Remove link dependency on i40e
Date: Tue, 22 May 2018 15:33:34 -0600	[thread overview]
Message-ID: <20180522213334.GE7502@mellanox.com> (raw)
In-Reply-To: <079ceee3bc8cd0ea50dd7ddc12b27512ca5ac49e.camel@intel.com>

On Tue, May 22, 2018 at 02:04:06PM -0700, Jeff Kirsher wrote:
> On Tue, 2018-05-22 at 14:56 -0600, Jason Gunthorpe wrote:
> > On Tue, May 22, 2018 at 01:38:31PM -0700, Jeff Kirsher wrote:
> > > From: Sindhu Devale <sindhu.devale@intel.com>
> > > 
> > > Currently i40iw is dependent on i40e symbols
> > > i40e_register_client and i40e_unregister_client due to
> > > which i40iw cannot be loaded without i40e being loaded.
> > > 
> > > This patch allows RDMA driver to build and load without
> > > linking to LAN driver and without LAN driver being loaded
> > > first. Once the LAN driver is loaded, the RDMA driver
> > > is notified through the netdevice notifiers to register
> > > as client to the LAN driver. Add function pointers to IDC
> > > register/unregister in the private VSI structure. This
> > > allows a RDMA driver to build without linking to i40e.
> > 
> > Why would you want to do this? The rdma driver is non-functional
> > without the ethernet driver, so why on earth would we want to defeat
> > the module dependency mechanism?
> 
> This change is driven by the OSV's like Red Hat, where customer's were
> updating the i40e driver, which in turn broke i40iw.

So that isn't a reason to put something into the main line kernel, and
I'm deeply skeptical this change is even sane.

It has been a while since I've looked at RH's kernel, but AFAIK,
breakage should only happen if the ABIs around
i40e_unregister_client/etc change..

So if the i40e module updates breaks the ABI, then stuffing that same
broken ABI through a function pointer is *totally* wrong.

Looks like a NAK for the RDMA side.

Jason

  reply	other threads:[~2018-05-22 21:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-22 20:38 Jeff Kirsher
2018-05-22 20:56 ` Jason Gunthorpe
2018-05-22 21:04   ` Jeff Kirsher
2018-05-22 21:33     ` Jason Gunthorpe [this message]
2018-05-22 21:50       ` Jeff Kirsher
2018-05-22 21:54         ` Jason Gunthorpe
2018-05-23  6:20         ` Christoph Hellwig
2018-05-23  6:19     ` Christoph Hellwig
2018-05-23 15:03       ` Alexander Duyck
2018-05-23 15:18         ` Jason Gunthorpe
2018-05-23 19:00 ` David Miller

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