Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757300Ab3CSTk5 (ORCPT ); Tue, 19 Mar 2013 15:40:57 -0400 Received: from webmail.solarflare.com ([12.187.104.25]:40303 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754455Ab3CSTkz (ORCPT ); Tue, 19 Mar 2013 15:40:55 -0400 Message-ID: <1363722051.3491.29.camel@bwh-desktop.uk.solarflarecom.com> Subject: Re: [RFC PATCH] Allow optional module parameters From: Ben Hutchings To: Rusty Russell CC: Andy Lutomirski , , , Jon Masters , Lucas De Marchi Date: Tue, 19 Mar 2013 19:40:51 +0000 In-Reply-To: <87hak8qfu5.fsf@rustcorp.com.au> References: <87ehfhtftn.fsf@rustcorp.com.au> <87sj3tsawh.fsf@rustcorp.com.au> <87hak8qfu5.fsf@rustcorp.com.au> Organization: Solarflare Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 (3.2.3-3.fc16) Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-Originating-IP: [10.17.20.137] X-TM-AS-Product-Ver: SMEX-10.0.0.1412-7.000.1014-19730.001 X-TM-AS-Result: No--28.807600-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2432 Lines: 59 On Tue, 2013-03-19 at 13:02 +1030, Rusty Russell wrote: > Andy Lutomirski writes: > > On Sun, Mar 17, 2013 at 7:24 PM, Rusty Russell wrote: > >> Andy Lutomirski writes: > >>> On Thu, Mar 14, 2013 at 10:03 PM, Rusty Russell wrote: > >>>> Err, yes. Don't remove module parameters, they're part of the API. Do > >>>> you have a particular example? > >>> > >>> So things like i915.i915_enable_ppgtt, which is there to enable > >>> something experimental, needs to stay forever once the relevant > >>> feature becomes non-experimental and non-optional? This seems silly. > ... > >>> Having the module parameter go away while still allowing the module to > >>> load seems like a good solution (possibly with a warning in the logs > >>> so the user can eventually delete the parameter). > >> > >> Why not do that for *every* missing parameter then? Why have this weird > >> notation where the user must know that the parameter might one day go > >> away? > > > > Fair enough. What about the other approach, then? Always warn if an > > option doesn't match (built-in or otherwise) but load the module > > anyways. > > What does everyone think of this? Jon, Lucas, does this match your > experience? I'm not sure why I'm being cc'd on this, though I did recently remove a module parameter (sfc.rx_alloc_method). For what it's worth: > Subject: modules: don't fail to load on unknown parameters. > > Although parameters are supposed to be part of the kernel API, experimental > parameters are often removed. In addition, downgrading a kernel might cause > previously-working modules to fail to load. > > On balance, it's probably better to warn, and load the module anyway. I agree with this. > Reported-by: Andy Lutomirski > Signed-off-by: Rusty Russell [...] This should also go to stable, so the downgrading issue doesn't continue to bite people. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/