Date: Mon, 18 Apr 2016 11:24:11 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Christoph Hellwig <hch@infradead.org>,
        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: <20160418182411.GA4904@infradead.org>
References: <20160414153727.6387.96381.stgit@scvm10.sc.intel.com>
 <20160414164550.GC6247@obsidianresearch.com>
 <20160418130909.GD11508@infradead.org>
 <20160418174047.GB13865@obsidianresearch.com>
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On Mon, Apr 18, 2016 at 11:40:47AM -0600, Jason Gunthorpe wrote:
> 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.

Well, it's stuff not related to our RDMA userspace API (which _is_
Verbs, not counting for the complete crackpot abuse in usnic), but
very device specific. 

The stuff the intel driver are doing isn't pretty, but unfortunately
not unusual either - lots of SCSI or network driver have ioctls
like that.  Now we could argue if the ioctls should be one the
main node (uverbs) or the a driver private chardev, or not exist
at all and people will have to patch the driver with some vendor
version if they really need it.  Examples for either of these
choices exist in the tree.