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=-5.3 required=3.0 tests=BAYES_00, 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 9E01CC64E8A for ; Mon, 30 Nov 2020 14:51:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AB5E820719 for ; Mon, 30 Nov 2020 14:51:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB5E820719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B44636B005D; Mon, 30 Nov 2020 09:51:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AF5158D0007; Mon, 30 Nov 2020 09:51:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9E2E38D0005; Mon, 30 Nov 2020 09:51:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0223.hostedemail.com [216.40.44.223]) by kanga.kvack.org (Postfix) with ESMTP id 8521A6B005D for ; Mon, 30 Nov 2020 09:51:54 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 45FF01F1B for ; Mon, 30 Nov 2020 14:51:54 +0000 (UTC) X-FDA: 77541374148.24.tub68_3315b62273a2 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 2D79C1A4A0 for ; Mon, 30 Nov 2020 14:51:54 +0000 (UTC) X-HE-Tag: tub68_3315b62273a2 X-Filterd-Recvd-Size: 2632 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Mon, 30 Nov 2020 14:51:53 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 3C4A86736F; Mon, 30 Nov 2020 15:51:50 +0100 (CET) Date: Mon, 30 Nov 2020 15:51:50 +0100 From: Christoph Hellwig To: Jan Kara Cc: Christoph Hellwig , Jens Axboe , Tejun Heo , Josef Bacik , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Johannes Thumshirn , dm-devel@redhat.com, Jan Kara , linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Chao Yu Subject: Re: [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Message-ID: <20201130145150.GA24694@lst.de> References: <20201128161510.347752-1-hch@lst.de> <20201128161510.347752-31-hch@lst.de> <20201130094421.GD11250@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201130094421.GD11250@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) 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 Mon, Nov 30, 2020 at 10:44:21AM +0100, Jan Kara wrote: > I know I'm like a broken record about this but I still don't understand > here... I'd expect the new code to be: > > if (size == capacity || > (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) > return false; > pr_info("%s: detected capacity change from %lld to %lld\n", > disk->disk_name, size, capacity); > + if (!capacity || !size) > + return false; > kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); > return true; > > At least that would be equivalent to the original functionality of > set_capacity_and_notify(). And if you indeed intend to change when > "RESIZE=1" events are sent, then I'd expect an explanation in the changelog > why this cannot break userspace (I remember we've already broken some udev > rules in the past by generating unexpected events and we had to revert > those changes in the partition code so I'm more careful now). The rest of > the patch looks good to me. I explained that I think the GENHD_FL_UP is the more useful one here in reply to your last comment. If the size changes to or from 0 during runtime we probably do want an event. But I'll add your hunk for now and we can discuss this separately.