From: Christoph Hellwig <hch@infradead.org>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: Bart Van Assche <bvanassche@acm.org>,
tj@kernel.org, josef@toxicpanda.com, jack@suse.cz,
axboe@kernel.dk, cgroups@vger.kernel.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com, yangerkun@huawei.com,
"yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [PATCH 2/2] blk-ioprio: remove per-disk structure
Date: Thu, 11 Jul 2024 22:22:29 -0700 [thread overview]
Message-ID: <ZpC9le_FsIO0FCJQ@infradead.org> (raw)
In-Reply-To: <520b9c10-c152-77f3-bd5a-b86a1f5ac8ea@huaweicloud.com>
On Fri, Jul 12, 2024 at 09:10:30AM +0800, Yu Kuai wrote:
> > As one can see in the output of git grep -nHEB1 '>pd_(alloc|free)_fn\(',
> > none of the pd_alloc_fn / pd_free_fn callers checks whether or not these
> > pointers are NULL. Hence my question why this patch does not trigger any
> > NULL pointer dereferences?
>
> Because the blkcg_deactivate_policy() is removed as well, there are no
> callers now... blkcg_policy_register() is still called to make sure
> cpd_(alloc|free)_fn will still be called.
Can you throw in a patch documenting this? Any maybe add a check
that pd_alloc_fn / pd_free_fn exist in blkcg_activate_policy and
WARN and return an error otherwise?
next prev parent reply other threads:[~2024-07-12 5:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-11 9:00 [PATCH 0/2] blk-ioprio: remove per-disk structure Yu Kuai
2024-07-11 9:00 ` [PATCH 1/2] blk-ioprio: remove ioprio_blkcg_from_bio() Yu Kuai
2024-07-11 18:00 ` Bart Van Assche
2024-07-11 9:00 ` [PATCH 2/2] blk-ioprio: remove per-disk structure Yu Kuai
2024-07-11 18:03 ` Bart Van Assche
2024-07-12 1:10 ` Yu Kuai
2024-07-12 1:25 ` Yu Kuai
2024-07-12 5:22 ` Christoph Hellwig [this message]
2024-07-12 6:51 ` Yu Kuai
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