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[2620:113:80c0:5::2222]) by mx.google.com with ESMTP id j3si569980eja.2.2019.03.20.05.20.16 for ; Wed, 20 Mar 2019 05:20:16 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning osalvador@suse.de does not designate 2620:113:80c0:5::2222 as permitted sender) client-ip=2620:113:80c0:5::2222; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning osalvador@suse.de does not designate 2620:113:80c0:5::2222 as permitted sender) smtp.mailfrom=osalvador@suse.de 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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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