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Date: Mon, 15 Dec 2025 06:31:53 +0100
From: Christoph Hellwig <hch@lst.de>
To: Yongpeng Yang <yangyongpeng.storage@gmail.com>
Cc: Damien Le Moal <dlemoal@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
	Yongpeng Yang <yangyongpeng@xiaomi.com>,
	Yongpeng Yang <yangyongpeng.storage@outlook.com>
Subject: Re: [PATCH v2 1/1] zloop: ensure atomicity of state checks in
 zloop_queue_rq
Message-ID: <20251215053153.GA30599@lst.de>
References: <20251213134545.207014-3-yangyongpeng.storage@gmail.com>
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On Sat, Dec 13, 2025 at 09:45:46PM +0800, Yongpeng Yang wrote:
> From: Yongpeng Yang <yangyongpeng@xiaomi.com>
> 
> The state check of zlo->state in zloop_queue_rq() fails to guarantee
> atomicity. This patch changes zlo->state to an atomic_t type variable,
> avoiding the use of the zloop_ctl_mutex lock for protection.

Err, no.  atomic_t for states is rarely a good idea.  And unless I'm
missing something this state check is just an optimization, so a
data_race() should be enough.  Either way this should probably first
be done and discussed for the loop code that has a lot more reviewers
and then ported to zloop.