Re: [PATCH v5 0/4] New Microsemi PCI Switch Management Driver

From: Bjorn Helgaas <helgaas@kernel.org>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: Keith Busch <keith.busch@intel.com>,
	Myron Stowe <myron.stowe@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Jonathan Corbet <corbet@lwn.net>,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Emil Velikov <emil.l.velikov@gmail.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	Wei Zhang <wzhang@fb.com>,
	Kurt Schwemmer <kurt.schwemmer@microsemi.com>,
	Stephen Bates <stephen.bates@microsemi.com>,
	linux-pci@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 0/4] New Microsemi PCI Switch Management Driver
Date: Wed, 1 Mar 2017 18:32:16 -0600	[thread overview]
Message-ID: <20170302003216.GC13171@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <d3d5567a-2147-43c5-d094-fb5345f02143@deltatee.com>

On Tue, Feb 28, 2017 at 10:11:56AM -0700, Logan Gunthorpe wrote:
> 
> > This driver doesn't have anything to do with the PCI core, other than
> > using the pci_register_driver() interface (just like all other drivers
> > for PCI-connected devices), so drivers/pci doesn't really feel like
> > the right place for it.  Putting it in drivers/pci leads to the sort
> > of confusion you mentioned above ("To make this entirely clear ...").
> > 
> > Would drivers/perf or drivers/misc/switchtec/ be possible places for
> > it?
> 
> I made a similar argument when we made the decision of where to put the
> code. In the end, the device _is_ a PCI Switch and someone going through
> menuconfig or the source tree would probably look there first.
> 
> As for drivers/perf, our device does a fair bit more than performance
> counters so it doesn't seem like it really fits in there. drivers/misc
> just seems like a dumping ground which we'd prefer not to contribute to.
> We also considered drivers/char (seeing it exposes a char device), but
> that also seems like a dumping ground with stuff that belongs and other
> stuff that just ended up stuck between the cracks.
> 
> If you still feel strongly about this we can move it into misc, but I
> think from an organizational perspective pci/switch makes a bit more sense.

It's not a perfect fit in drivers/pci because it's not bus
infrastructure and I don't want to be the default maintainer of it,
but I agree there's not really an alternative that's clearly better,
so let's leave it where it is for now.

> In any case, I also wish we could have had this discussion 3 months ago
> when we posted the RFC and not when I have people pushing to get this
> merged.

You and me both!  I hope some of those same people are pushing to help
avoid the tragedy of the commons by helping review other
contributions.

Bjorn