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,URIBL_BLOCKED autolearn=unavailable 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 A562FC43387 for ; Wed, 2 Jan 2019 12:55:41 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8B0692171F for ; Wed, 2 Jan 2019 12:55:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B0692171F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43V9yL2PmzzDqL5 for ; Wed, 2 Jan 2019 23:55:38 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=jejb@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43ST0z29MdzDqGh for ; Mon, 31 Dec 2018 05:06:55 +1100 (AEDT) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBUHx6TC088654 for ; Sun, 30 Dec 2018 13:06:53 -0500 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0b-001b2d01.pphosted.com with ESMTP id 2ppppujk3w-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 30 Dec 2018 13:06:53 -0500 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 30 Dec 2018 18:06:52 -0000 Received: from b03cxnp07029.gho.boulder.ibm.com (9.17.130.16) by e35.co.us.ibm.com (192.168.1.135) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Sun, 30 Dec 2018 18:06:47 -0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBUI6krn13172922 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Sun, 30 Dec 2018 18:06:47 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7D7B97806A; Sun, 30 Dec 2018 18:06:46 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8A3E278064; Sun, 30 Dec 2018 18:06:44 +0000 (GMT) Received: from [153.66.254.194] (unknown [9.80.193.237]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Sun, 30 Dec 2018 18:06:44 +0000 (GMT) Subject: Re: [PATCH v8 01/25] scsi/atari_scsi: Don't select CONFIG_NVRAM From: James Bottomley To: LEROY Christophe , Arnd Bergmann Date: Sun, 30 Dec 2018 10:06:43 -0800 In-Reply-To: <20181230185002.Horde.AdSknvcs4hP1Kh_T_Cos6w8@messagerie.si.c-s.fr> 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18123018-0012-0000-0000-000016F14095 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010317; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000272; SDB=6.01139345; UDB=6.00592790; IPR=6.00919542; MB=3.00024903; MTD=3.00000008; XFM=3.00000015; UTC=2018-12-30 18:06:50 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18123018-0013-0000-0000-000055A18D29 Message-Id: <1546193203.2844.9.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-12-30_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812300166 X-Mailman-Approved-At: Wed, 02 Jan 2019 23:53:24 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michael Schmitz , linux-scsi , "Martin K. Petersen" , Greg Kroah-Hartman , Linux Kernel Mailing List , Finn Thain , linux-m68k , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, 2018-12-30 at 18:50 +0100, LEROY Christophe wrote: > Arnd Bergmann a écrit : > > On Sat, Dec 29, 2018 at 3:51 AM Michael Schmitz > > wrote: [...] > > > (On second thought - I don't want to speculate whether there's > > > weird compiler options that could result in the > > > nvram_check_checksum and nvram_read_bytes symbols to still be > > > referenced in the final link, even though > > > IS_BUILTIN(CONFIG_NVRAM) always evaluates to false. Best > > > leave this as-is.) > > > > As far as I know, it's totally reliable with the supported > > compilers (gcc-4.6+). In the older compilers (e.g. 4.1), there was > > a corner case, where it could have failed to eliminate a function > > that was only referenced through a pointer from a discarded > > variable, but a plain IS_ENABLED() check like the one here > > was still ok, and lots of code relies on that. > > > > Other than that, I agree either way is totally fine here, so no > > objections to using the #ifdef. > > As far as I know, kernel codying style promotes the use of > IS_ENABLED() etc. instead of #ifdefs when possible. It's a preference, as with a lot of coding style stuff, which we leave up to the maintainer. 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). James