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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 B97AAC07E96 for ; Thu, 15 Jul 2021 06:52:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9492061370 for ; Thu, 15 Jul 2021 06:52:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231298AbhGOGy7 (ORCPT ); Thu, 15 Jul 2021 02:54:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230016AbhGOGy7 (ORCPT ); Thu, 15 Jul 2021 02:54:59 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69C55C06175F for ; Wed, 14 Jul 2021 23:52:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RytKYXm4KX75fZPuEx0/hV8/+9xmwDuSUAB8ht171wA=; b=mltIaCBwgrX66P0slkl+2j+B2M rQrOgnmLTMAs3lfTc48w2haDkZU6ODizMF0ERmJ3rMuFv0dicbWjMOJPX/JnCvz3KxRNLIeWd4lYJ p2k/zVvo9eyxktFhj7M7A+IB3rD/y6eYaoUCVplS4x2lsGcYtleIjrvsbUqF19Fz1rhUZ3iIo898m 5pR0/tPZYKxv5WrYNtBOK0Y6HmGquYQ1rZo54fWqsFBUDvSURWyJSIyVljogEZAMWU3B7HrqWo/K0 3P8MEpaaYnzPWhWoYO30Y7EfyoH0uLrNLrkKkqDc4oN7qnSoCsLQEcvD8yh41zwsc53k67cIJXoRK PEvqzC1A==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m3vAy-0034Lh-O9; Thu, 15 Jul 2021 06:49:15 +0000 Date: Thu, 15 Jul 2021 07:48:52 +0100 From: Christoph Hellwig To: Joao Martins Cc: linux-mm@kvack.org, Dan Williams , Vishal Verma , Dave Jiang , Naoya Horiguchi , Matthew Wilcox , Jason Gunthorpe , John Hubbard , Jane Chu , Muchun Song , Mike Kravetz , Andrew Morton , Jonathan Corbet , nvdimm@lists.linux.dev, linux-doc@vger.kernel.org Subject: Re: [PATCH v3 04/14] mm/memremap: add ZONE_DEVICE support for compound pages Message-ID: References: <20210714193542.21857-1-joao.m.martins@oracle.com> <20210714193542.21857-5-joao.m.martins@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210714193542.21857-5-joao.m.martins@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org > +static inline unsigned long pgmap_geometry(struct dev_pagemap *pgmap) > +{ > + if (!pgmap || !pgmap->geometry) > + return PAGE_SIZE; > + return pgmap->geometry; Nit, but avoiding all the negations would make this a little easier to read: if (pgmap && pgmap->geometry) return pgmap->geometry; return PAGE_SIZE > + if (pgmap_geometry(pgmap) > PAGE_SIZE) > + percpu_ref_get_many(pgmap->ref, (pfn_end(pgmap, range_id) > + - pfn_first(pgmap, range_id)) / pgmap_pfn_geometry(pgmap)); > + else > + percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id) > + - pfn_first(pgmap, range_id)); This is a horrible undreadable mess, which is trivially fixed by a strategically used local variable: refs = pfn_end(pgmap, range_id) - pfn_first(pgmap, range_id); if (pgmap_geometry(pgmap) > PAGE_SIZE) refs /= pgmap_pfn_geometry(pgmap); percpu_ref_get_many(pgmap->ref, refs);