From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA617C43387 for ; Sun, 30 Dec 2018 22:45:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7211120828 for ; Sun, 30 Dec 2018 22:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726900AbeL3WpW (ORCPT ); Sun, 30 Dec 2018 17:45:22 -0500 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:34502 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726861AbeL3WpW (ORCPT ); Sun, 30 Dec 2018 17:45:22 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by kvm5.telegraphics.com.au (Postfix) with ESMTP id 42EE12280E; Sun, 30 Dec 2018 17:45:18 -0500 (EST) Date: Mon, 31 Dec 2018 09:45:16 +1100 (AEDT) From: Finn Thain To: James Bottomley cc: LEROY Christophe , Arnd Bergmann , linuxppc-dev , linux-m68k , Linux Kernel Mailing List , Greg Kroah-Hartman , "Martin K. Petersen" , linux-scsi , Michael Schmitz Subject: Re: [PATCH v8 01/25] scsi/atari_scsi: Don't select CONFIG_NVRAM In-Reply-To: Message-ID: References: <20181228173846.Horde.z_zDEJN0rVd8tkt3HjYzmg2@messagerie.si.c-s.fr> <5e901432-65e2-c87b-31e3-36a394687a9a@gmail.com> <20181230185002.Horde.AdSknvcs4hP1Kh_T_Cos6w8@messagerie.si.c-s.fr> <1546193203.2844.9.camel@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 31 Dec 2018, Finn Thain wrote: > On Sun, 30 Dec 2018, James Bottomley wrote: > > > > > That said, as has been pointed out, the current #ifdef has a failing > > corner case when both are modular (because the code should then be > > included). The runtime macro that correctly expresses this is > > IS_REACHABLE(CONFIG_NVRAM). > > > > No, in the case of CONFIG_NVRAM=m, the conditional code is deliberately > excluded. This is discussed in the patch description. The convention on > PPC32 is that device drivers drop support for NVRAM in this situation. > > I've adopted the PPC32 convention here because M68K drivers and PPC32 > drivers have to co-exist (I'm thinking of valkyriefb, but there are other > examples). > I agree with your comment in principle, that these drivers should be using IS_REACHABLE(CONFIG_NVRAM), not defined(CONFIG_NVRAM). $ grep -lrw CONFIG_NVRAM drivers/ drivers/video/fbdev/matrox/matroxfb_base.c drivers/video/fbdev/platinumfb.c drivers/video/fbdev/controlfb.c drivers/video/fbdev/valkyriefb.c drivers/video/fbdev/imsttfb.c drivers/scsi/atari_scsi.c $ But I think this is not the fault of this patch; it's just a historical accident. Having said that, I will rework this series to convert all of the above drivers to IS_REACHABLE(CONFIG_NVRAM). I think it would be an improvement. Besides, it seems likely that some rework involving ppc_md will be needed too because as Arnd pointed out, it would be good to avoid two sets of nvram accessor methods. --