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Date: Thu, 10 Mar 2022 07:38:46 +0100
From: Christoph Hellwig <hch@lst.de>
To: Niels Dossche <dossche.niels@gmail.com>
Cc: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
 Sagi Grimberg <sagi@grimberg.me>, Chaitanya Kulkarni <kch@nvidia.com>,
 Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH v2] nvmet: add missing locks around nvmet_ns_revalidate
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On Thu, Mar 10, 2022 at 02:25:11AM +0100, Niels Dossche wrote:
> nvmet_ns_changed states via lockdep that the ns->subsys->lock must be
> held. The only caller of nvmet_ns_changed which does not acquire that
> lock is nvmet_ns_revalidate.

So acquire it in nvmet_ns_revalidate only when we actually call
nvmet_ns_changed.  Otherwise we take a subsystem-wide lock for every
Identify Namespace all.