From: Jens Axboe <axboe@kernel.dk>
To: Tejun Heo <tj@kernel.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>,
Waiman Long <longman@redhat.com>, Yu Kuai <yukuai3@huawei.com>,
Josef Bacik <josef@toxicpanda.com>,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2] blk_iocost: remove some duplicate irq disable/enables
Date: Thu, 3 Oct 2024 16:06:28 -0600 [thread overview]
Message-ID: <d5b34514-aa3a-47dc-9521-d2774c1785a2@kernel.dk> (raw)
In-Reply-To: <Zv8NBM4mOVoMoBQS@slm.duckdns.org>
On 10/3/24 3:30 PM, Tejun Heo wrote:
> On Thu, Oct 03, 2024 at 11:22:09AM -1000, Tejun Heo wrote:
>> Yeah, that should be spin_lock_irq() for consistency but at the same time it
>> doesn't look like anything is actually grabbing that lock (or blkcg->lock
>> nesting outside of it) from an IRQ context, so no actual deadlock scenario
>> exists and lockdep doesn't trigger.
>
> Oh, wait, it's not that. blkg_conf_prep() implies queue_lock, so the IRQ is
> disabled around it and adding _irq will trigger lockdep.
Ah makes sense, didn't realize it was nested under the queue lock. Then it
does look like it's just that one spot.
--
Jens Axboe
next prev parent reply other threads:[~2024-10-03 22:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-02 10:47 [PATCH v2] blk_iocost: remove some duplicate irq disable/enables Dan Carpenter
2024-10-02 13:17 ` Jens Axboe
2024-10-02 17:49 ` Waiman Long
2024-10-02 18:10 ` Dan Carpenter
2024-10-02 18:40 ` Waiman Long
2024-10-03 12:03 ` Dan Carpenter
2024-10-03 13:21 ` Jens Axboe
2024-10-03 14:31 ` Dan Carpenter
2024-10-03 14:38 ` Jens Axboe
2024-10-03 15:49 ` Waiman Long
2024-10-03 16:24 ` Jens Axboe
2024-10-03 21:22 ` Tejun Heo
2024-10-03 21:30 ` Tejun Heo
2024-10-03 22:06 ` Jens Axboe [this message]
2024-10-04 10:53 ` Dan Carpenter
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