Date:   Wed, 15 Dec 2021 23:46:31 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
        nvdimm@lists.linux.dev, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, djwong@kernel.org,
        dan.j.williams@intel.com, david@fromorbit.com, jane.chu@oracle.com
Subject: Re: [PATCH v8 7/9] dax: add dax holder helper for filesystems
Message-ID: <Ybru12651I+lETBq@infradead.org>
References: <20211202084856.1285285-1-ruansy.fnst@fujitsu.com>
 <20211202084856.1285285-8-ruansy.fnst@fujitsu.com>
 <Ybi8pmieExZbd/Ee@infradead.org>
 <2c0d1b44-5b7f-f4d0-a7ca-0cf692a0cdd4@fujitsu.com>
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On Wed, Dec 15, 2021 at 10:21:00AM +0800, Shiyang Ruan wrote:
> 
> 
> 在 2021/12/14 23:47, Christoph Hellwig 写道:
> > On Thu, Dec 02, 2021 at 04:48:54PM +0800, Shiyang Ruan wrote:
> > > Add these helper functions, and export them for filesystem use.
> > 
> > What is the point of adding these wrappers vs just calling the
> > underlying functions?
> 
> I added them so that they can be called in a friendly way, even if
> CONFIG_DAX is off.  Otherwise, we need #if IS_ENABLED(CONFIG_DAX) to wrap
> them where they are called.

No need for wrappers, you can stub out the underlying functions as well.