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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 A7124C6379D for ; Fri, 20 Nov 2020 07:43:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B3DF222BA for ; Fri, 20 Nov 2020 07:43:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726556AbgKTHnF (ORCPT ); Fri, 20 Nov 2020 02:43:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:36314 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725818AbgKTHnE (ORCPT ); Fri, 20 Nov 2020 02:43:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E6A77AB3D; Fri, 20 Nov 2020 07:43:02 +0000 (UTC) Subject: Re: [PATCH 65/78] dm: remove the block_device reference in struct mapped_device To: Christoph Hellwig , Jens Axboe Cc: Justin Sanders , Josef Bacik , Ilya Dryomov , Jack Wang , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Minchan Kim , Mike Snitzer , Song Liu , "Martin K. Petersen" , dm-devel@redhat.com, linux-block@vger.kernel.org, drbd-dev@lists.linbit.com, nbd@other.debian.org, ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20201116145809.410558-1-hch@lst.de> <20201116145809.410558-66-hch@lst.de> From: Hannes Reinecke Message-ID: <310bff8b-dbda-609a-a392-619733b86bd1@suse.de> Date: Fri, 20 Nov 2020 08:43:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201116145809.410558-66-hch@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On 11/16/20 3:57 PM, Christoph Hellwig wrote: > Get rid of the long-lasting struct block_device reference in > struct mapped_device. The only remaining user is the freeze code, > where we can trivially look up the block device at freeze time > and release the reference at thaw time. > > Signed-off-by: Christoph Hellwig > --- > drivers/md/dm-core.h | 2 -- > drivers/md/dm.c | 22 +++++++++++----------- > 2 files changed, 11 insertions(+), 13 deletions(-) > > diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h > index d522093cb39dda..b1b400ed76fe90 100644 > --- a/drivers/md/dm-core.h > +++ b/drivers/md/dm-core.h > @@ -107,8 +107,6 @@ struct mapped_device { > /* kobject and completion */ > struct dm_kobject_holder kobj_holder; > > - struct block_device *bdev; > - > struct dm_stats stats; > > /* for blk-mq request-based DM support */ > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 6d7eb72d41f9ea..c789ffea2badde 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1744,11 +1744,6 @@ static void cleanup_mapped_device(struct mapped_device *md) > > cleanup_srcu_struct(&md->io_barrier); > > - if (md->bdev) { > - bdput(md->bdev); > - md->bdev = NULL; > - } > - > mutex_destroy(&md->suspend_lock); > mutex_destroy(&md->type_lock); > mutex_destroy(&md->table_devices_lock); > @@ -1840,10 +1835,6 @@ static struct mapped_device *alloc_dev(int minor) > if (!md->wq) > goto bad; > > - md->bdev = bdget_disk(md->disk, 0); > - if (!md->bdev) > - goto bad; > - > dm_stats_init(&md->stats); > > /* Populate the mapping, nobody knows we exist yet */ > @@ -2384,12 +2375,17 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) > */ > static int lock_fs(struct mapped_device *md) > { > + struct block_device *bdev; > int r; > > WARN_ON(md->frozen_sb); > > - md->frozen_sb = freeze_bdev(md->bdev); > + bdev = bdget_disk(md->disk, 0); > + if (!bdev) > + return -ENOMEM; > + md->frozen_sb = freeze_bdev(bdev); > if (IS_ERR(md->frozen_sb)) { > + bdput(bdev); > r = PTR_ERR(md->frozen_sb); > md->frozen_sb = NULL; > return r; > @@ -2402,10 +2398,14 @@ static int lock_fs(struct mapped_device *md) > > static void unlock_fs(struct mapped_device *md) > { > + struct block_device *bdev; > + > if (!test_bit(DMF_FROZEN, &md->flags)) > return; > > - thaw_bdev(md->bdev, md->frozen_sb); > + bdev = md->frozen_sb->s_bdev; > + thaw_bdev(bdev, md->frozen_sb); > + bdput(bdev); > md->frozen_sb = NULL; > clear_bit(DMF_FROZEN, &md->flags); > } > Yay. Just what I need for the blk-interposer code, where the ->bdev pointer is really getting in the way. Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer