From patchwork Wed Feb 12 17:07:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 11378839 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C29C513A4 for ; Wed, 12 Feb 2020 17:08:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F64321734 for ; Wed, 12 Feb 2020 17:08:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JgKFBE/+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728903AbgBLRID (ORCPT ); Wed, 12 Feb 2020 12:08:03 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:52259 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728410AbgBLRIC (ORCPT ); Wed, 12 Feb 2020 12:08:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581527278; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=uVtVcsiKhkuKKf+gRgkYGjwkWDveu2K52NRmmgOy/F0=; b=JgKFBE/+dnsXhH2r9vBJypHWD+ZJdagUdWJN2rFC96VpLGAWaR2CCimDc4gQecyKZWxTos rx/AW9yxn+OpHb6TXzJg1POHMplhEbxPB+4a2iUwqmzYD4zNzFSQEDGzYHgRhx1QnoFeGH eKqUu8G+XrnsY9dcooVXFSQB4GeBg0U= 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-282-w09-80CIMHqzsasM6BehBw-1; Wed, 12 Feb 2020 12:07:51 -0500 X-MC-Unique: w09-80CIMHqzsasM6BehBw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BCD1EDBA5; Wed, 12 Feb 2020 17:07:49 +0000 (UTC) Received: from horse.redhat.com (unknown [10.18.25.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2445C89F30; Wed, 12 Feb 2020 17:07:47 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id AAF6C220A24; Wed, 12 Feb 2020 12:07:46 -0500 (EST) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, hch@infradead.org Cc: vgoyal@redhat.com, dm-devel@redhat.com, jack@suse.cz Subject: [RFC PATCH 0/6] dax: Replace bdev_dax_pgoff() with dax_pgoff() Date: Wed, 12 Feb 2020 12:07:27 -0500 Message-Id: <20200212170733.8092-1-vgoyal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Currently dax code assumes that there is always a block device associated with it. And block device is passed around in few routines. I am implementing DAX support for virtiofs and there is no block device while we are using dax device. So I need dax code to move away from this assumption that there is always a block device. We seem to pass around block deivce only to calculate the partition offset into dax device. bdev_dax_pgoff() does get_start_sect(bdev). There are two proposed solutions to this problem. - Get rid of kernel partition support for pmem devices. - Caller stores offset into dax device and passes that in along with dax_device. First solution was discussed recently in this thread. https://lore.kernel.org/linux-fsdevel/20200107125159.GA15745@infradead.org/ I feel we already shipped partition support for dax block devices and going back now will be painful and its easy to break users out there which are using partitions. Hence I thought of writing patches for second proposal and see how bad it looks. To me patches are fairly small and don't break backward compatibility and seem like a good step in the direction of removing dax assumptions about block device. So I am posting this RFC patch series, which is just boot tested. Any feedback or comments are welcome. Thanks Vivek Vivek Goyal (6): dax: Define a helper dax_pgoff() which takes in dax_offset as argument dax,iomap,ext4,ext2,xfs: Save dax_offset in "struct iomap" fs/dax.c: Start using dax_pgoff() instead of bdev_dax_pgoff() dax, dm/md: Use dax_pgoff() instead of bdev_dax_pgoff() drivers/dax: Use dax_pgoff() instead of bdev_dax_pgoff() dax: Remove bdev_dax_pgoff() helper drivers/dax/super.c | 11 +++++------ drivers/md/dm-linear.c | 9 ++++++--- drivers/md/dm-log-writes.c | 9 ++++++--- drivers/md/dm-stripe.c | 8 +++++--- fs/dax.c | 13 ++++++------- fs/ext2/inode.c | 1 + fs/ext4/inode.c | 1 + fs/xfs/xfs_iomap.c | 2 ++ include/linux/dax.h | 2 +- include/linux/iomap.h | 1 + 10 files changed, 34 insertions(+), 23 deletions(-)