From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Maciej W. Rozycki" Subject: Re: [PATCH 080/493] fddi: remove use of __devexit_p Date: Wed, 21 Nov 2012 23:49:50 +0000 (GMT) Message-ID: References: <1353349642-3677-1-git-send-email-wfp5p@virginia.edu> <1353349642-3677-80-git-send-email-wfp5p@virginia.edu> <20121119192949.GA16976@kroah.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Bill Pemberton , netdev@vger.kernel.org To: Greg KH Return-path: Received: from arrakis.dune.hu ([78.24.191.176]:37307 "EHLO eddie.linux-mips.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754093Ab2KVTAZ (ORCPT ); Thu, 22 Nov 2012 14:00:25 -0500 Received: from localhost.localdomain ([127.0.0.1]:44805 "EHLO localhost.localdomain" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6828054Ab2KUXturht0N (ORCPT ); Thu, 22 Nov 2012 00:49:50 +0100 In-Reply-To: <20121119192949.GA16976@kroah.com> Sender: netdev-owner@vger.kernel.org List-ID: Greg, > > I have unconfused myself now, so please replace the above with the > > following question: what about configurations (e.g. buses) that not > > support hotplug at all? For example apart from PCI the defxx driver > > concerned here supports the TURBOchannel bus that by design does not have > > the concept of live option card removal (no such circuitry). So should > > now the precious memory be wasted on systems that will never ever handle > > hotplug? > > CONFIG_HOTPLUG is always enabled now, so that's not an option anymore. > And again, a user can "hot unbind" a driver from a device from > userspace, no matter if the bus physically supports it or not. Hmm, what purpose does this serve for devices that cannot be physically removed? If there is none, shouldn't that policy be set by individual drivers or platform even? Even if HOTPLUG as a whole is unconditional (I suppose the amount of space core support itself takes is much less to what driver code can). TURBOchannel, although valid, is an old exotic case that might not be worth arguing for, except for purity maybe. But there are surely many contemporary systems out there that are known they are never going to support hot device replacement. Consider most of the embedded systems for example, where devices may even physically be cast into a single SOC (with no prospect of chipping off any pieces ever ;) ), that certainly could not care less of device replacement, but they do care a lot about memory consumption. Was this implication considered, discussed and diregarded as not important enough compared to benefits from hardcoding HOTPLUG support? I'm seriously asking for a pointer, not trying to cause any stir-up -- regrettably I fail to follow most discussions these days, but I would like to know what the background behind this decision was. Thanks a lot! Maciej