From patchwork Fri Jan 12 15:06:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 10161245 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3995C602D8 for ; Fri, 12 Jan 2018 15:06:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F24BF2880A for ; Fri, 12 Jan 2018 15:06:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E670C28830; Fri, 12 Jan 2018 15:06:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 805FC2880A for ; Fri, 12 Jan 2018 15:06:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933968AbeALPGe (ORCPT ); Fri, 12 Jan 2018 10:06:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50476 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933917AbeALPGd (ORCPT ); Fri, 12 Jan 2018 10:06:33 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6A3C9550B0; Fri, 12 Jan 2018 15:06:33 +0000 (UTC) Received: from localhost (ovpn-112-12.rdu2.redhat.com [10.10.112.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2FECC7D501; Fri, 12 Jan 2018 15:06:30 +0000 (UTC) From: Mike Snitzer To: axboe@kernel.dk Cc: Ming Lei , hare@suse.de, Bart.VanAssche@wdc.com, David Jeffery , dm-devel@redhat.com, linux-block@vger.kernel.org Subject: [for-4.16 PATCH v5 4/4] dm: fix incomplete request_queue initialization Date: Fri, 12 Jan 2018 10:06:06 -0500 Message-Id: <20180112150606.6037-5-snitzer@redhat.com> In-Reply-To: <20180112150606.6037-1-snitzer@redhat.com> References: <20180112150606.6037-1-snitzer@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 12 Jan 2018 15:06:33 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP DM is no longer prone to having its request_queue be improperly initialized. Summary of changes: - defer DM's blk_register_queue() from add_disk()-time until dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev(). - dm_setup_md_queue() is updated to fully initialize DM's request_queue (_after_ all table loads have occurred and the request_queue's type, features and limits are known). A very welcome side-effect of these changes is DM no longer needs to: 1) backfill the "mq" sysfs entry (because historically DM didn't initialize the request_queue to use blk-mq until _after_ blk_register_queue() was called via add_disk()). 2) call elv_register_queue() to get .request_fn request-based DM device's "iosched" exposed in syfs. In addition, blk-mq debugfs support is now made available because request-based DM's blk-mq request_queue is now properly initialized before dm_setup_md_queue() calls blk_register_queue(). These changes also stave off the need to introduce new DM-specific workarounds in block core, e.g. this proposal: https://patchwork.kernel.org/patch/10067961/ In the end DM devices should be less unicorn in nature (relative to initialization and availability of block core infrastructure provided by the request_queue). Signed-off-by: Mike Snitzer Tested-by: Ming Lei --- drivers/md/dm-rq.c | 9 --------- drivers/md/dm.c | 11 ++++++++++- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 9d32f25489c2..c28357f5cb0e 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -713,8 +713,6 @@ int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t) return error; } - elv_register_queue(md->queue); - return 0; } @@ -812,15 +810,8 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) } dm_init_md_queue(md); - /* backfill 'mq' sysfs registration normally done in blk_register_queue */ - err = blk_mq_register_dev(disk_to_dev(md->disk), q); - if (err) - goto out_cleanup_queue; - return 0; -out_cleanup_queue: - blk_cleanup_queue(q); out_tag_set: blk_mq_free_tag_set(md->tag_set); out_kfree_tag_set: diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 7475739fee49..8c26bfc35335 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1761,7 +1761,7 @@ static struct mapped_device *alloc_dev(int minor) goto bad; md->dax_dev = dax_dev; - add_disk(md->disk); + add_disk_no_queue_reg(md->disk); format_dev_t(md->name, MKDEV(_major, minor)); md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0); @@ -2021,6 +2021,7 @@ EXPORT_SYMBOL_GPL(dm_get_queue_limits); int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) { int r; + struct queue_limits limits; enum dm_queue_mode type = dm_get_md_type(md); switch (type) { @@ -2057,6 +2058,14 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) break; } + r = dm_calculate_queue_limits(t, &limits); + if (r) { + DMERR("Cannot calculate initial queue limits"); + return r; + } + dm_table_set_restrictions(t, md->queue, &limits); + blk_register_queue(md->disk); + return 0; }