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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 AB145C3A59B for ; Sat, 17 Aug 2019 03:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CE9521743 for ; Sat, 17 Aug 2019 03:35:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="unNNdQ25" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726357AbfHQDfB (ORCPT ); Fri, 16 Aug 2019 23:35:01 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:48578 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbfHQDfB (ORCPT ); Fri, 16 Aug 2019 23:35:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=amkkG0fFLqOV5ST5JcqKziuKz5rtlbB6iQXsDBoiTrs=; b=unNNdQ25SMlyL0bMYg9BMDQyH evQOVq5s2u5MkwLkoNQP4Q7lz9gsoSmXrZTvYb66/KdDOwr4W5/vThPxWIP2Ty6m9V2Y5wu6UvAD2 mFFi0mKg/E4NvzbyVMPHoDVPZo39v1zuZxzFQZYz4bcbl/wnXR7idyqHiO0fTNkn9U9Gi6ZhqDBcY N6Z6cTpftFRYL4FbopyTWozBZFGK8z8tn6h0C4ffo4tBs35chF3/CjR1mdSrPAIwnBOzwOlerkbfN nALHNGXzeAg6F7BKg2ldDTI+ze7qoWVDr/FKVaHd1v/gAXOwcnm7YJIqniPVi/197MhmSA7ZAMxZW 0lENUUw9A==; Received: from willy by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1hypUI-0002m8-46; Sat, 17 Aug 2019 03:34:42 +0000 Date: Fri, 16 Aug 2019 20:34:42 -0700 From: Matthew Wilcox To: Zhaoyang Huang Cc: Andrew Morton , Zhaoyang Huang , Russell King , Mike Rapoport , Rob Herring , Florian Fainelli , Geert Uytterhoeven , Doug Berger , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arch : arm : add a criteria for pfn_valid Message-ID: <20190817033441.GD18474@bombadil.infradead.org> References: <1566010813-27219-1-git-send-email-huangzhaoyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1566010813-27219-1-git-send-email-huangzhaoyang@gmail.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 17, 2019 at 11:00:13AM +0800, Zhaoyang Huang wrote: > #ifdef CONFIG_HAVE_ARCH_PFN_VALID > int pfn_valid(unsigned long pfn) > { > - return memblock_is_map_memory(__pfn_to_phys(pfn)); > + return (pfn > max_pfn) ? > + false : memblock_is_map_memory(__pfn_to_phys(pfn)); > } This is a really awkward way to use the ternary operator. It's easier to read if you just: + if (pfn > max_pfn) + return 0; return memblock_is_map_memory(__pfn_to_phys(pfn)); (if you really wanted to be clever ... er, obscure, you'd've written: return (pfn <= max_pfn) && memblock_is_map_memory(__pfn_to_phys(pfn)); ... but don't do that) Also, why is this diverged between arm and arm64?