From: Christoph Hellwig <hch@lst.de>
To: Jan Kara <jack@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Dan Schatzberg <schatzberg.dan@gmail.com>,
kernel test robot <oliver.sang@intel.com>,
Jan Stancek <jstancek@redhat.com>,
linux-block <linux-block@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] loop: use task_work for autoclear operation
Date: Mon, 10 Jan 2022 17:40:54 +0100 [thread overview]
Message-ID: <20220110164054.GA7047@lst.de> (raw)
In-Reply-To: <20220110134234.qebxn5gghqupsc7t@quack3.lan>
On Mon, Jan 10, 2022 at 02:42:34PM +0100, Jan Kara wrote:
> I see. But:
> a) We didn't fully establish a real deadlock scenario from the lockdep
> report, did we? The lockdep report involved suspend locks, some locks on
> accessing files in /proc etc. and it was not clear whether it all reflects
> a real deadlock possibility or just a fact that lockdep tracking is rather
> coarse-grained at times. Now lockdep report is unpleasant and loop device
> locking was ugly anyway so your async change made sense but once lockdep is
> silenced we should really establish whether there is real deadlock and more
> work is needed or not.
>
> b) Unless we have a realistic plan of moving *all* blk_mq_freeze_queue()
> calls from under open_mutex in loop driver, moving stuff "where possible"
> from under open_mutex is IMO just muddying water.
Agreed. I also have to say I'm not a fan of proliferating the use of
task_work_add.
prev parent reply other threads:[~2022-01-10 16:40 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-07 11:00 [PATCH v2 1/2] block: export task_work_add() Tetsuo Handa
2022-01-07 11:04 ` [PATCH v2 2/2] loop: use task_work for autoclear operation Tetsuo Handa
2022-01-10 6:20 ` Jan Stancek
2022-01-10 10:30 ` Jan Kara
2022-01-10 11:28 ` Tetsuo Handa
2022-01-10 13:42 ` Jan Kara
2022-01-10 15:08 ` Tetsuo Handa
2022-01-12 13:16 ` Jan Kara
2022-01-12 14:00 ` Tetsuo Handa
2022-01-13 15:23 ` Jan Kara
2022-01-14 11:05 ` Tetsuo Handa
2022-01-14 16:05 ` Jan Kara
2022-01-13 10:44 ` Jan Kara
2022-01-14 15:50 ` Tetsuo Handa
2022-01-14 19:58 ` Jan Kara
2022-01-15 0:34 ` Tetsuo Handa
2022-01-17 8:15 ` Christoph Hellwig
2022-01-17 9:34 ` Tetsuo Handa
2022-01-17 14:10 ` Tetsuo Handa
2022-01-18 15:58 ` Tetsuo Handa
2022-01-18 16:15 ` Christoph Hellwig
2022-01-20 14:20 ` Christoph Hellwig
2022-01-20 15:42 ` Jan Kara
2022-01-10 16:40 ` Christoph Hellwig [this message]
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