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	id AC58E68BEB; Thu,  7 May 2026 07:49:44 +0200 (CEST)
Date: Thu, 7 May 2026 07:49:44 +0200
From: Christoph Hellwig <hch@lst.de>
To: Chao Shi <coshi036@gmail.com>
Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, hch@lst.de,
	kbusch@kernel.org, sagi@grimberg.me, axboe@kernel.dk,
	Sungwoo Kim <iam@sung-woo.kim>, Dave Tian <daveti@purdue.edu>,
	Weidong Zhu <weizhu@fiu.edu>
Subject: Re: [PATCH RFC 2/2] nvme: set integrity metadata size for EXT_LBAS
 non-PI namespace
Message-ID: <20260507054944.GB19796@lst.de>
References: <20260427003457.1264511-1-coshi036@gmail.com> <20260427003457.1264511-2-coshi036@gmail.com>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Sun, Apr 26, 2026 at 08:34:57PM -0400, Chao Shi wrote:
> +		/*
> +		 * For PCIe EXT_LBAS non-PI namespaces the block layer sets
> +		 * capacity to 0 (we return false) to prevent block I/O, but a
> +		 * cached-rq bio may bypass bio_queue_enter freeze serialisation
> +		 * and reach nvme_setup_rw() with head->ms != 0 and no
> +		 * REQ_INTEGRITY set.  Populate bi->metadata_size so that
> +		 * bio_integrity_action() returns non-zero and bio_integrity_prep()
> +		 * sets REQ_INTEGRITY on any such bio, preventing the WARN_ON_ONCE
> +		 * at nvme_setup_rw() (addressed by patch 1/2).

This sounds like the Bug Keith is trying to fix in the block layer
("blk-mq: check for stale cached request in blk_mq_submit_bio") ?