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Date:   Tue, 5 Sep 2023 10:33:08 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Daniel Wagner <dwagner@suse.de>
Cc:     Christoph Hellwig <hch@lst.de>, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
        Sagi Grimberg <sagi@grimberg.me>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        James Smart <james.smart@broadcom.com>,
        Chaitanya Kulkarni <kch@nvidia.com>
Subject: Re: [RFC v1 1/4] nvmet-trace: avoid dereferencing pointer too early
Message-ID: <20230905083308.GA20920@lst.de>
References: <20230829091350.16156-1-dwagner@suse.de> <20230829091350.16156-2-dwagner@suse.de> <20230905064846.GA19701@lst.de> <77nt3zr7rap6w7bpvm6vfdqqf4xc46afq4tzlifsn3zlry5wvh@t2e6orslw6on>
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On Tue, Sep 05, 2023 at 10:24:51AM +0200, Daniel Wagner wrote:
> On Tue, Sep 05, 2023 at 08:48:46AM +0200, Christoph Hellwig wrote:
> > > +static inline u16 nvmet_req_to_ctrl_id(struct nvmet_req *req)
> > >  {
> > > -	return req->sq->ctrl;
> > > +	if (!req->sq || !req->sq->ctrl)
> > > +		return 0;
> > > +	return req->sq->ctrl->cntlid;
> > 
> > Can you add a comment here why we have this check?
> 
> /*
>  * The queue and controller pointer are not valid until an
>  * association has been established.
>  */

sounds good.