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Date: Tue, 17 Dec 2024 08:19:28 +0100
From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 1/2] block: avoid to hold q->limits_lock across APIs
 for atomic update queue limits
Message-ID: <20241217071928.GA19884@lst.de>
References: <20241216080206.2850773-1-ming.lei@redhat.com> <20241216080206.2850773-2-ming.lei@redhat.com> <20241216154901.GA23786@lst.de> <Z2DZc1cVzonHfMIe@fedora> <20241217044056.GA15764@lst.de> <Z2EizLh58zjrGUOw@fedora>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Tue, Dec 17, 2024 at 03:05:48PM +0800, Ming Lei wrote:
> On Tue, Dec 17, 2024 at 05:40:56AM +0100, Christoph Hellwig wrote:
> > On Tue, Dec 17, 2024 at 09:52:51AM +0800, Ming Lei wrote:
> > > The local copy can be updated in any way with any data, so does another
> > > concurrent update on q->limits really matter?
> > 
> > Yes, because that means one of the updates get lost even if it is
> > for entirely separate fields.
> 
> Right, but the limits are still valid anytime.
> 
> Any suggestion for fixing this deadlock?

What is "this deadlock"?