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mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.onmicrosoft.com; s=selector2-citrix-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=a4b9FBabi2Zvy5ESdh9529MReJHNaekB3PL7uFvPI3g=; b=K84O7HglJRBVJx5yjDu/XPph/mtar4qxMmgC9NansM/i5UiY6UQ3qnvQ+TiObn3R2YskK5pf41TzfrFvut40bZwwBfOKSmncWn2lg0z7LHKQ1r94Lqh1+SDhL0IO67Q0Yb3f8MTGou6t+6xXPK/CokjPZW1nK+dhCVTra2l6rMY= Date: Tue, 2 Mar 2021 11:57:46 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich CC: "xen-devel@lists.xenproject.org" , Andrew Cooper , Wei Liu , George Dunlap , Ian Jackson Subject: Re: [PATCH 2/2][4.15?] x86: fix build when NR_CPUS == 1 Message-ID: References: <1d8d5089-32a9-9c42-5949-8f9cd20f33e0@suse.com> <9b0a5689-fced-d986-3bfb-9ade47cf3635@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <9b0a5689-fced-d986-3bfb-9ade47cf3635@suse.com> X-ClientProxiedBy: AM6P191CA0015.EURP191.PROD.OUTLOOK.COM (2603:10a6:209:8b::28) To DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 1c2c2c17-5ace-4f25-a64d-08d8dd6a076d X-MS-TrafficTypeDiagnostic: DM6PR03MB3833: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; 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It seemed more logical to me to place it > >> next to where the issue is. > > > > I'm not sure whether I would prefer to place it in per_cpu directly to > > avoid similar issues popping up in other parts of the code in the > > future? > > That's going to be a lot of BUG_ON(), and hence a lot of "ud2" > instances. Not something I'm keen on having. The more that it's > not the per_cpu() which triggers the warning, but separate > conditionals allowing the compiler to deduce value ranges of > variables. Right. I don't see much other way around this then. Did you check with clang also? Acked-by: Roger Pau Monné Thanks, Roger.