From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id 70CBA420171 for ; Wed, 5 Jul 2023 18:12:26 +0200 (CEST) Date: Wed, 5 Jul 2023 18:12:25 +0200 From: Jan Kara To: Bart Van Assche Message-ID: <20230705161225.cwig5a3mo6oz7lew@quack3> References: <20230629165206.383-1-jack@suse.cz> <20230704122224.16257-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Cc: Dave Kleikamp , jfs-discussion@lists.sourceforge.net, Jan Kara , "Darrick J. Wong" , linux-nvme@lists.infradead.org, Joseph Qi , dm-devel@redhat.com, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, Jack Wang , Alasdair Kergon , drbd-dev@lists.linbit.com, linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, Sergey Senozhatsky , Christoph Hellwig , xen-devel@lists.xenproject.org, Gao Xiang , Christian Borntraeger , Kent Overstreet , Sven Schnelle , linux-pm@vger.kernel.org, Mike Snitzer , Chao Yu , Joern Engel , reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, David Sterba , Jaegeuk Kim , Trond Myklebust , Jens Axboe , linux-raid@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, Ted Tso , linux-mm@kvack.org, Song Liu , linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, Minchan Kim , ocfs2-devel@oss.oracle.com, Anna Schumaker , linux-fsdevel@vger.kernel.org, "Md. Haris Iqbal" , Andrew Morton , linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Subject: Re: [Drbd-dev] [PATCH 01/32] block: Provide blkdev_get_handle_* functions List-Id: "*Coordination* of development, patches, contributions -- *Questions* \(even to developers\) go to drbd-user, please." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue 04-07-23 07:06:26, Bart Van Assche wrote: > On 7/4/23 05:21, Jan Kara wrote: > > +struct bdev_handle { > > + struct block_device *bdev; > > + void *holder; > > +}; > > Please explain in the patch description why a holder pointer is introduced > in struct bdev_handle and how it relates to the bd_holder pointer in struct > block_device. Is one of the purposes of this patch series perhaps to add > support for multiple holders per block device? No. The reason for adding holder to struct bdev_handle is that it is an argument blkdev_put() needs. Currently, every user of blkdev_put() has to remember what it has passed as 'holder' to blkdev_get_by_*() call and pass that to blkdev_put(). With struct bdev_handle this will happen automatically. This is already explained in the changelog of this patch: "Create struct bdev_handle that contains all parameters that need to be passed to blkdev_put()..." If it was only about holder, the intrusive patches would not be warranted but as the description also says: "This will eventually allow us to pass one more argument to blkdev_put() without too much hassle." Because we will additionaly need to propagate the 'mode' argument used at open to blkdev_put(). Honza -- Jan Kara SUSE Labs, CR