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Date: Tue, 21 Sep 2021 08:32:09 +0200
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>, Ira Weiny <ira.weiny@intel.com>,
	linux-block@vger.kernel.org, Linux NVDIMM <nvdimm@lists.linux.dev>
Subject: Re: [PATCH 3/3] block: warn if ->groups is set when calling
 add_disk
Message-ID: <20210921063209.GA23736@lst.de>
References: <20210920072726.1159572-1-hch@lst.de> <20210920072726.1159572-4-hch@lst.de> <CAPcyv4iVL7bevm_MeFnkRK12SkwO4k5aR3-4KOAGMxThmJwOuA@mail.gmail.com>
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On Mon, Sep 20, 2021 at 04:50:03PM -0700, Dan Williams wrote:
> >
> >         ddev->parent = parent;
> > -       ddev->groups = groups;
> > +       if (!WARN_ON_ONCE(ddev->groups))
> > +               ddev->groups = groups;
> 
> That feels too compact to me, and dev_WARN_ONCE() might save someone a
> git blame to look up the reason for the warning:
> 
>     dev_WARN_ONCE(parent, ddev->groups, "unexpected pre-populated
> attribute group\n");
>     if (!ddev->groups)
>         ddev->groups = groups;
> 
> ...but not a deal breaker. Either way you can add:
> 

I'd rather keep it simple and optmize for the normal case..