Date: Mon, 18 Apr 2016 11:40:47 -0600
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>, dledford@redhat.com,
        linux-rdma@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/7] IB/hfi1: Remove write() and use ioctl() for user
 access
Message-ID: <20160418174047.GB13865@obsidianresearch.com>
References: <20160414153727.6387.96381.stgit@scvm10.sc.intel.com>
 <20160414164550.GC6247@obsidianresearch.com>
 <20160418130909.GD11508@infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20160418130909.GD11508@infradead.org>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1550
Lines: 32

On Mon, Apr 18, 2016 at 06:09:09AM -0700, Christoph Hellwig wrote:
> On Thu, Apr 14, 2016 at 10:45:50AM -0600, Jason Gunthorpe wrote:
> > On Thu, Apr 14, 2016 at 08:41:35AM -0700, Dennis Dalessandro wrote:
> > > This patch series removes the write() interface for user access in favor of an
> > > ioctl() based approach. This is in response to the complaint that we had
> > > different handlers for write() and writev() doing different things and expecting
> > > different types of data. See:
> > 
> > I think we should wait on applying these patches until we globally sort out
> > what to do with the rdma uapi.
> > 
> > It just doesn't make alot of sense for drivers to have their own personal
> > char devices. :(
> 
> I looked through the patches I tend to disagree - while we should wait
> for a global UAPI for anything that's actually RDMA/verbs related these
> seem to be misc little bits specific to the driver that have no business
> in any sort of generic RDMA API.

I wasn't arguing this should integrate into verbs in some way, only
that the way to access the driver-specific uAPI of a RDMA device should
be through the RDMA common uAPI and not through a random char dev.

.. and of course that the driver-specific API be subject to a sane
review and use of the normal standards, not just written off as
driver-garbage nobody cares about. :(

For instance, if we had a driver specific channel, it casts this
endless stream of uAPI verbs patches in a different light: maybe they
should go down the driver-specific channel instead.

Jason