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[2620:137:e000::1:20]) by mx.google.com with ESMTP id q5-20020a17090a304500b00263e299dff6si6997363pjl.74.2023.07.31.01.04.04; Mon, 31 Jul 2023 01:04:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=T9eeIHYX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229697AbjGaH31 (ORCPT + 99 others); Mon, 31 Jul 2023 03:29:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232382AbjGaH3I (ORCPT ); Mon, 31 Jul 2023 03:29:08 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7AE430D4; Mon, 31 Jul 2023 00:26:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=la9vCumXxx+thsCuV36iYTwTzNB80cwXHoef713V7Qg=; b=T9eeIHYXmNPGSPnCFwtK+zgU5S cYk8EAhh0XSe6erfq7j1UKpmPsS9kcrBXf+l/Ak2ctbOmNBk9sXN98ILVoOlMTcQAkKIEdOPYP6GO Z/TwuTEP9GafmzL8ZEGwPwlY3WZFsaFT9AJiK3FdbFXq23yC5QHi8o2oqozFKHwUGqLsml94+WLO6 R1E4oGUSh2BhDM12tZS5E1gvvtQr1+NU2ayqCfUTbcko9SgDl+DwD2igU9ZuQTL7X3YfW/2LFdP6l BIeVErVwoSeiQAswK0CXxTM5brhrTfVctrh+Ach/5cx4dcTj5DGFrAJl74mAXW6tuqwwwzvsD3ZI7 388e3qnw==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qQNI9-00EJQ7-2D; Mon, 31 Jul 2023 07:26:09 +0000 Date: Mon, 31 Jul 2023 00:26:09 -0700 From: Christoph Hellwig To: Jinyoung Choi Cc: "song@kernel.org" , "linux-raid@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "pmenzel@molgen.mpg.de" Subject: Re: [PATCH v2] md/bitmap: Avoid protection error writing bitmap page with block integrity Message-ID: References: <20230720092957epcms2p6cbd0ecdf7f5bf0db3c04eefaf0a6644d@epcms2p6> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230720092957epcms2p6cbd0ecdf7f5bf0db3c04eefaf0a6644d@epcms2p6> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 20, 2023 at 06:29:57PM +0900, Jinyoung Choi wrote: > Changing the bitmap page is also possible on the page where the DMA is > being performed or scheduled in the MD. Are you guys actually using the whacky bitmap feature? If so, this really is the least of our problems and you need to invest some real work into it to get it off ->bmap and into using ->read_iter and ->write_iter. Right now Song has a series from me queued up to deprecated it. I also don't think a simple wait for existing writers prevents you from other modifications, but maybe I'm issing something.