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=-13.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 6B748C83012 for ; Wed, 2 Dec 2020 15:13:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B9AD20B1F for ; Wed, 2 Dec 2020 15:13:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728300AbgLBPMr (ORCPT ); Wed, 2 Dec 2020 10:12:47 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:35977 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727116AbgLBPMq (ORCPT ); Wed, 2 Dec 2020 10:12:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606921880; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BI29tL8haMOOy0hp46ljwCMGR3G48eRovDB8MadITvs=; b=Tanx0uce/dSE/N8PQ5f0mWNWppEo7igVg1qXZoPL4HByWAMQP3J/jCFasNIkZ1pDHJ3PTt t1Yg6MHsxPZHt/5zlVByF8SFDLg6fxaxv95j4vvRr66p7srfZOb5SrbMM4jROZ/UcBTgob q9aUriw+2II4yQL53uqIpxG6EI9aZRU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-518-nlBjB5GxPkG3Og55m4gtcQ-1; Wed, 02 Dec 2020 10:11:18 -0500 X-MC-Unique: nlBjB5GxPkG3Og55m4gtcQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A5F5B805BE8; Wed, 2 Dec 2020 15:11:17 +0000 (UTC) Received: from localhost (unknown [10.18.25.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8CC246086F; Wed, 2 Dec 2020 15:11:13 +0000 (UTC) Date: Wed, 2 Dec 2020 10:11:12 -0500 From: Mike Snitzer To: JeffleXu Cc: dm-devel@redhat.com, joseph.qi@linux.alibaba.com, linux-block@vger.kernel.org Subject: Re: dm: use gcd() to fix chunk_sectors limit stacking Message-ID: <20201202151112.GD20535@redhat.com> References: <20201201160709.31748-1-snitzer@redhat.com> <20201202033855.60882-1-jefflexu@linux.alibaba.com> <20201202033855.60882-2-jefflexu@linux.alibaba.com> <20201202050343.GA20535@redhat.com> <7326607a-b687-3989-dee7-cf469ab37ac4@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7326607a-b687-3989-dee7-cf469ab37ac4@linux.alibaba.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Dec 02 2020 at 2:10am -0500, JeffleXu wrote: > > > On 12/2/20 1:03 PM, Mike Snitzer wrote: > > What you've done here is fairly chaotic/disruptive: > > 1) you emailed a patch out that isn't needed or ideal, I dealt already > > staged a DM fix in linux-next for 5.10-rcX, see: > > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.10-rcX&id=f28de262ddf09b635095bdeaf0e07ff507b3c41b > > Then ti->type->io_hints() is still bypassed when type->iterate_devices() > not defined? Yes, the stacking of limits really is tightly coupled to device-based influence. Hypothetically some DM target that doesn't remap to any data devices may want to override limits... in practice there isn't a need for this. If that changes we can take action to accommodate it.. but I'm definitely not interested in modifying DM core in this area when there isn't a demonstrated need. Mike