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Date: Tue, 4 Jul 2023 13:43:51 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Jan Kara <jack@suse.cz>
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Cc: Dave Kleikamp <shaggy@kernel.org>, jfs-discussion@lists.sourceforge.net,
	"Darrick J. Wong" <djwong@kernel.org>, linux-nvme@lists.infradead.org,
	Joseph Qi <joseph.qi@linux.alibaba.com>, dm-devel@redhat.com,
	target-devel@vger.kernel.org, linux-mtd@lists.infradead.org,
	Jack Wang <jinpu.wang@ionos.com>,
	Alasdair Kergon <agk@redhat.com>, drbd-dev@lists.linbit.com,
	linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org,
	linux-scsi@vger.kernel.org, Sergey Senozhatsky <senozhatsky@chromium.org>,
	Christoph Hellwig <hch@infradead.org>,
	xen-devel@lists.xenproject.org, Gao Xiang <xiang@kernel.org>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Kent Overstreet <kent.overstreet@gmail.com>,
	Sven Schnelle <svens@linux.ibm.com>, linux-pm@vger.kernel.org,
	Mike Snitzer <snitzer@kernel.org>, Chao Yu <chao@kernel.org>,
	Joern Engel <joern@lazybastard.org>,
	reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org,
	linux-bcache@vger.kernel.org, David Sterba <dsterba@suse.com>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Jens Axboe <axboe@kernel.dk>, linux-raid@vger.kernel.org,
	linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	Ted Tso <tytso@mit.edu>, linux-mm@kvack.org, Song Liu <song@kernel.org>,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-xfs@vger.kernel.org, Minchan Kim <minchan@kernel.org>,
	ocfs2-devel@oss.oracle.com, Anna Schumaker <anna@kernel.org>,
	linux-fsdevel@vger.kernel.org, "Md. Haris Iqbal" <haris.iqbal@ionos.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org
Subject: Re: [Drbd-dev] [PATCH 01/32] block: Provide blkdev_get_handle_*
	functions
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On Tue, Jul 04, 2023 at 02:21:28PM +0200, Jan Kara wrote:
> +struct bdev_handle *blkdev_get_handle_by_dev(dev_t dev, blk_mode_t mode,
> +		void *holder, const struct blk_holder_ops *hops)
> +{
> +	struct bdev_handle *handle = kmalloc(sizeof(struct bdev_handle),
> +					     GFP_KERNEL);
> +	struct block_device *bdev;
> +
> +	if (!handle)
> +		return ERR_PTR(-ENOMEM);
> +	bdev = blkdev_get_by_dev(dev, mode, holder, hops);
> +	if (IS_ERR(bdev))
> +		return ERR_CAST(bdev);

Would we be better off with a handle->error (and a NULL return from this
function means "we couldn't allocate a handle")?  I have no objection
to what you've done here, just wondering if it might end up nicer for
the users.