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Date:   Wed, 12 Apr 2023 13:45:03 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Damien Le Moal <dlemoal@kernel.org>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Bart Van Assche <bvanassche@acm.org>,
        linux-block@vger.kernel.org
Subject: Re: [PATCH 08/18] blk-mq: fold __blk_mq_insert_req_list into
 blk_mq_insert_request
Message-ID: <20230412114503.GA8979@lst.de>
References: <20230412053248.601961-1-hch@lst.de> <20230412053248.601961-9-hch@lst.de> <fd0e02c6-8fbb-cb7b-4925-331c132aeb7a@kernel.org> <20230412072009.GA21504@lst.de> <d95970c1-1fea-7e35-e29b-6013d2ba42e1@kernel.org>
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On Wed, Apr 12, 2023 at 04:33:04PM +0900, Damien Le Moal wrote:
> On 4/12/23 16:20, Christoph Hellwig wrote:
> > On Wed, Apr 12, 2023 at 04:16:36PM +0900, Damien Le Moal wrote:
> >>>  	} else {
> >>> +		trace_block_rq_insert(rq);
> >>
> >> Shouldn't we keep the trace call under ctx->lock to preserve precise tracing ?
> > 
> > ctx->lock doesn't synchronize any of the in the request that is traced
> > here.
> 
> I am not worried about the values shown by the trace entries, but rather the
> order of the inserts: with the trace call outside the lock, the trace may end up
> showing an incorrect insertion order ?

Maybe.  I can respin the series and move it back under the lock.