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From: Niels Dossche <dossche.niels@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-nvme@lists.infradead.org, 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
Date: Thu, 10 Mar 2022 13:46:22 +0100	[thread overview]
Message-ID: <9a019440-98a5-983e-0fbb-ef9bed0193a6@gmail.com> (raw)
In-Reply-To: <20220310063846.GA24359@lst.de>

On 10/03/2022 07:38, Christoph Hellwig wrote:
> 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.

There are 3 callers of nvmet_ns_revalidate, of which 2 do not acquire the lock and 1 does.
I'll send a v3 patch which does the locking locally inside that if check by adding an additional argument to indicate whether the lock should be acquired or not.
Thanks.


      reply	other threads:[~2022-03-10 12:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-10  1:25 [PATCH v2] nvmet: add missing locks around nvmet_ns_revalidate Niels Dossche
2022-03-10  1:50 ` Chaitanya Kulkarni
2022-03-10  6:38 ` Christoph Hellwig
2022-03-10 12:46   ` Niels Dossche [this message]

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