From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DDD41360 for ; Wed, 23 Mar 2022 05:46:25 +0000 (UTC) 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=7ZAsD6U+OpZrl9q+vvF5BO0Ld/peFEuasZX9wg8w/7c=; b=nlGt60I9cy8CABM8dFM997RIev lf+Vu/g9DqcVUJgBuwjYjHU9jOV3QQCh4gomYHEWmUbee1hju7Vb6RO0DEA9S5CmbmQe/zXKweFXn 8EVK7EgUoutyRvQb8bI9IhY1/UZJtuu/qqg9kSmpHJ1YGuAsMtO/ZauNT7m3eiq2M7Urm1DDCQ6cy u9yF+0Tbj77cKFKrTYwHSOfN80W+1eYN9ITP5OdtfmjQfHxk1qXo0WX7STlhFRN4cS2UgCMWDrFen cyC6TLzVbiAgxvrwxolPd8ULMLpgLYxqVhw8SAFfUge+NFNrjR50q2wFlEV6DOACqQ0c/5lF0epQv 0VigWM/g==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWtok-00CoLR-Fp; Wed, 23 Mar 2022 05:45:58 +0000 Date: Tue, 22 Mar 2022 22:45:58 -0700 From: Christoph Hellwig To: Jane Chu Cc: Christoph Hellwig , "david@fromorbit.com" , "djwong@kernel.org" , "dan.j.williams@intel.com" , "vishal.l.verma@intel.com" , "dave.jiang@intel.com" , "agk@redhat.com" , "snitzer@redhat.com" , "dm-devel@redhat.com" , "ira.weiny@intel.com" , "willy@infradead.org" , "vgoyal@redhat.com" , "linux-fsdevel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-xfs@vger.kernel.org" Subject: Re: [PATCH v6 4/6] dax: add DAX_RECOVERY flag and .recovery_write dev_pgmap_ops Message-ID: References: <20220319062833.3136528-1-jane.chu@oracle.com> <20220319062833.3136528-5-jane.chu@oracle.com> <3dabd58b-70f2-12af-419f-a7dfc07fbb1c@oracle.com> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3dabd58b-70f2-12af-419f-a7dfc07fbb1c@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Mar 22, 2022 at 11:05:09PM +0000, Jane Chu wrote: > > This DAX_RECOVERY doesn't actually seem to be used anywhere here or > > in the subsequent patches. Did I miss something? > > dax_iomap_iter() uses the flag in the same patch, > + if ((map_len == -EIO) && (iov_iter_rw(iter) == WRITE)) { > + flags |= DAX_RECOVERY; > + map_len = dax_direct_access(dax_dev, pgoff, nrpg, > + flags, &kaddr, NULL); Yes, it passes it on to dax_direct_access, and dax_direct_access passes it onto ->direct_access. But nothing in this series actually checks for it as far as I can tell. > >> Also introduce a new dev_pagemap_ops .recovery_write function. > >> The function is applicable to FSDAX device only. The device > >> page backend driver provides .recovery_write function if the > >> device has underlying mechanism to clear the uncorrectable > >> errors on the fly. > > > > Why is this not in struct dax_operations? > > Per Dan's comments to the v5 series, adding .recovery_write to > dax_operations causes a number of trivial dm targets changes. > Dan suggested that adding .recovery_write to pagemap_ops could > cut short the logistics of figuring out whether the driver backing > up a page is indeed capable of clearing poison. Please see > https://lkml.org/lkml/2022/2/4/31 But at least in this series there is 1:1 association between the pgmap and the dax_device so that scheme won't work. It would have to lookup the pgmap based on the return physical address from dax_direct_access. Which sounds more complicated than just adding the (annoying) boilerplate code to DM. > include/linux/memremap.h doesn't know struct iov_iter which is defined > in include/linux/uio.h, would you prefer to adding include/linux/uio.h > to include/linux/memremap.h ? As it is not derefences just adding a struct iov_iter; line to memremap.h below the includes should be all that is needed. 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 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 70D0EC433EF for ; Wed, 23 Mar 2022 06:08:44 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-472-ZaG_ysGsO7SuBTzJOmpDUQ-1; Wed, 23 Mar 2022 02:08:39 -0400 X-MC-Unique: ZaG_ysGsO7SuBTzJOmpDUQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 79A01185A7A4; Wed, 23 Mar 2022 06:08:37 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB0414B8D43; Wed, 23 Mar 2022 06:08:34 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 8B9231940340; Wed, 23 Mar 2022 06:08:32 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 9CF361949762 for ; Wed, 23 Mar 2022 06:08:31 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 2301D40D2823; Wed, 23 Mar 2022 06:08:31 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast07.extmail.prod.ext.rdu2.redhat.com [10.11.55.23]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1ECBE40D2820 for ; Wed, 23 Mar 2022 06:08:30 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D19373C01B80 for ; Wed, 23 Mar 2022 06:08:30 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-511-Vrp3m0PLNNCX5el9SOxB2A-1; Wed, 23 Mar 2022 02:08:27 -0400 X-MC-Unique: Vrp3m0PLNNCX5el9SOxB2A-1 Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWtok-00CoLR-Fp; Wed, 23 Mar 2022 05:45:58 +0000 Date: Tue, 22 Mar 2022 22:45:58 -0700 From: Christoph Hellwig To: Jane Chu Message-ID: References: <20220319062833.3136528-1-jane.chu@oracle.com> <20220319062833.3136528-5-jane.chu@oracle.com> <3dabd58b-70f2-12af-419f-a7dfc07fbb1c@oracle.com> MIME-Version: 1.0 In-Reply-To: <3dabd58b-70f2-12af-419f-a7dfc07fbb1c@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Subject: Re: [dm-devel] [PATCH v6 4/6] dax: add DAX_RECOVERY flag and .recovery_write dev_pgmap_ops X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "nvdimm@lists.linux.dev" , "dave.jiang@intel.com" , "snitzer@redhat.com" , "djwong@kernel.org" , "david@fromorbit.com" , "linux-kernel@vger.kernel.org" , "willy@infradead.org" , Christoph Hellwig , "dm-devel@redhat.com" , "vgoyal@redhat.com" , "vishal.l.verma@intel.com" , "linux-fsdevel@vger.kernel.org" , "dan.j.williams@intel.com" , "ira.weiny@intel.com" , "linux-xfs@vger.kernel.org" , "agk@redhat.com" Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Mar 22, 2022 at 11:05:09PM +0000, Jane Chu wrote: > > This DAX_RECOVERY doesn't actually seem to be used anywhere here or > > in the subsequent patches. Did I miss something? > > dax_iomap_iter() uses the flag in the same patch, > + if ((map_len == -EIO) && (iov_iter_rw(iter) == WRITE)) { > + flags |= DAX_RECOVERY; > + map_len = dax_direct_access(dax_dev, pgoff, nrpg, > + flags, &kaddr, NULL); Yes, it passes it on to dax_direct_access, and dax_direct_access passes it onto ->direct_access. But nothing in this series actually checks for it as far as I can tell. > >> Also introduce a new dev_pagemap_ops .recovery_write function. > >> The function is applicable to FSDAX device only. The device > >> page backend driver provides .recovery_write function if the > >> device has underlying mechanism to clear the uncorrectable > >> errors on the fly. > > > > Why is this not in struct dax_operations? > > Per Dan's comments to the v5 series, adding .recovery_write to > dax_operations causes a number of trivial dm targets changes. > Dan suggested that adding .recovery_write to pagemap_ops could > cut short the logistics of figuring out whether the driver backing > up a page is indeed capable of clearing poison. Please see > https://lkml.org/lkml/2022/2/4/31 But at least in this series there is 1:1 association between the pgmap and the dax_device so that scheme won't work. It would have to lookup the pgmap based on the return physical address from dax_direct_access. Which sounds more complicated than just adding the (annoying) boilerplate code to DM. > include/linux/memremap.h doesn't know struct iov_iter which is defined > in include/linux/uio.h, would you prefer to adding include/linux/uio.h > to include/linux/memremap.h ? As it is not derefences just adding a struct iov_iter; line to memremap.h below the includes should be all that is needed. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel