From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id CDE138E004D for ; Tue, 11 Dec 2018 00:09:56 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id o21so6384918edq.4 for ; Mon, 10 Dec 2018 21:09:56 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id ge18-v6sor3659994ejb.16.2018.12.10.21.09.55 for (Google Transport Security); Mon, 10 Dec 2018 21:09:55 -0800 (PST) Date: Tue, 11 Dec 2018 05:09:53 +0000 From: Wei Yang Subject: Re: [PATCH] mm, sparse: remove check with __highest_present_section_nr in for_each_present_section_nr() Message-ID: <20181211050953.nj3kwmwzhprsam5z@master> Reply-To: Wei Yang References: <20181211035128.43256-1-richard.weiyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181211035128.43256-1-richard.weiyang@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wei Yang Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com, osalvador@suse.de On Tue, Dec 11, 2018 at 11:51:28AM +0800, Wei Yang wrote: >A valid present section number is in [0, __highest_present_section_nr]. >And the return value of next_present_section_nr() meets this >requirement. This means it is not necessary to check it with ^ , if it is not (-1) Would like to add this to be more exact. >__highest_present_section_nr again in for_each_present_section_nr(). > >Since we pass an unsigned long *section_nr* to >for_each_present_section_nr(), we need to cast it to int before >comparing. > >Signed-off-by: Wei Yang >--- > mm/sparse.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > >diff --git a/mm/sparse.c b/mm/sparse.c >index a4fdbcb21514..9eaa8f98a3d2 100644 >--- a/mm/sparse.c >+++ b/mm/sparse.c >@@ -197,8 +197,7 @@ static inline int next_present_section_nr(int section_nr) > } > #define for_each_present_section_nr(start, section_nr) \ > for (section_nr = next_present_section_nr(start-1); \ >- ((section_nr >= 0) && \ >- (section_nr <= __highest_present_section_nr)); \ >+ (int)section_nr >= 0; \ > section_nr = next_present_section_nr(section_nr)) > > static inline unsigned long first_present_section_nr(void) >-- >2.15.1 -- Wei Yang Help you, Help me