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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham 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 5998DC43381 for ; Wed, 20 Mar 2019 12:20:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 190E82075C for ; Wed, 20 Mar 2019 12:20:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727599AbfCTMUR (ORCPT ); Wed, 20 Mar 2019 08:20:17 -0400 Received: from charybdis-ext.suse.de ([195.135.221.2]:16898 "EHLO suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726366AbfCTMUQ (ORCPT ); Wed, 20 Mar 2019 08:20:16 -0400 Received: by suse.de (Postfix, from userid 1000) id 6683C4622; Wed, 20 Mar 2019 13:20:15 +0100 (CET) Date: Wed, 20 Mar 2019 13:20:15 +0100 From: Oscar Salvador To: Matthew Wilcox Cc: Baoquan He , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, pasha.tatashin@oracle.com, mhocko@suse.com, rppt@linux.vnet.ibm.com, richard.weiyang@gmail.com, linux-mm@kvack.org Subject: Re: [PATCH 1/3] mm/sparse: Clean up the obsolete code comment Message-ID: <20190320122011.stuoqugpjdt3d7cd@d104.suse.de> References: <20190320073540.12866-1-bhe@redhat.com> <20190320111959.GV19508@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190320111959.GV19508@bombadil.infradead.org> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 20, 2019 at 04:19:59AM -0700, Matthew Wilcox wrote: > On Wed, Mar 20, 2019 at 03:35:38PM +0800, Baoquan He wrote: > > /* > > - * returns the number of sections whose mem_maps were properly > > - * set. If this is <=0, then that means that the passed-in > > - * map was not consumed and must be freed. > > + * sparse_add_one_section - add a memory section > > + * @nid: The node to add section on > > + * @start_pfn: start pfn of the memory range > > + * @altmap: device page map > > + * > > + * Return 0 on success and an appropriate error code otherwise. > > */ > > I think it's worth documenting what those error codes are. Seems to be > just -ENOMEM and -EEXIST, but it'd be nice for users to know what they > can expect under which circumstances. > > Also, -EEXIST is a bad errno to return here: > > $ errno EEXIST > EEXIST 17 File exists > > What file? I think we should be using -EBUSY instead in case this errno > makes it back to userspace: > > $ errno EBUSY > EBUSY 16 Device or resource busy We return -EEXIST in case the section we are trying to add is already there, and that error is being caught by __add_pages(), which ignores the error in case is -EXIST and keeps going with further sections. Sure we can change that for -EBUSY, but I think -EEXIST makes more sense, plus that kind of error is never handed back to userspace. -- Oscar Salvador SUSE L3