From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org
Subject: Re: [PATCH] blk-cgroup: delay calling blkcg_exit_disk until disk_release
Date: Thu, 9 Feb 2023 07:47:38 +0800 [thread overview]
Message-ID: <Y+Q0mp1cV3Ca6bAf@T590> (raw)
In-Reply-To: <20230208151231.GA16018@lst.de>
On Wed, Feb 08, 2023 at 04:12:31PM +0100, Christoph Hellwig wrote:
> On Wed, Feb 08, 2023 at 03:38:40PM +0800, Ming Lei wrote:
> > > This now can cause a case where disk_release is called on a disk
> > > that hasn't been added. That's mostly harmless, except for a case
> > > in blk_throttl_exit that now needs to check for a NULL ->td pointer.
> >
> > With this way, blkcg_init_disk() could be called before q->root_blkg
> > is released in disk unbind & rebind use case, then memory leak?
>
> q->root_blkg is now disk->root_blkg. So in an unind and rebind case
> a different disk will be involved.
OK.
Another thing is that blkcg_init_disk() and blkcg_exit_disk() becomes
asymmetrical with this patch. So alloc_disk() & add_disk(), del_disk() & put_disk()
have to be done together. If it may be documented, this patch looks
fine.
Thanks,
Ming
next prev parent reply other threads:[~2023-02-08 23:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-08 6:35 [PATCH] blk-cgroup: delay calling blkcg_exit_disk until disk_release Christoph Hellwig
2023-02-08 7:38 ` Ming Lei
2023-02-08 15:12 ` Christoph Hellwig
2023-02-08 23:47 ` Ming Lei [this message]
2023-02-09 5:04 ` Christoph Hellwig
2023-02-09 8:56 ` Ming Lei
2023-02-09 15:12 ` Jens Axboe
2023-02-10 5:05 ` Ming Lei
2023-02-13 8:37 ` Ming Lei
2023-02-13 8:42 ` Christoph Hellwig
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