linux-ext4 - Re: [PATCH 01/32] block: Provide blkdev_get_handle

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Message-ID: <20230705102128.vquve4qencbbn2br@quack3>
Date:   Wed, 5 Jul 2023 12:21:28 +0200
From:   Jan Kara <jack@...e.cz>
To:     Keith Busch <kbusch@...nel.org>
Cc:     Jan Kara <jack@...e.cz>, linux-block@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
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Subject: Re: [PATCH 01/32] block: Provide blkdev_get_handle_* functions

On Tue 04-07-23 10:28:36, Keith Busch wrote:
> 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);
> 
> I believe 'sizeof(*handle)' is the preferred style.

OK.

> > +	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);
> 
> Need a 'kfree(handle)' before the error return. Or would it be simpler
> to get the bdev first so you can check the mode settings against a
> read-only bdev prior to the kmalloc?

Yeah. Good point with kfree(). I'm not sure calling blkdev_get_by_dev()
first will be "simpler" - then we need blkdev_put() in case of kmalloc()
failure. Thanks for review!
 
								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR