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Date:   Tue, 23 Nov 2021 19:10:48 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        gladkov.alexey@gmail.com, LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v2] fs: proc: store PDE()->data into inode->i_private
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On Mon, 22 Nov 2021 12:13:33 +0800 Muchun Song <songmuchun@bytedance.com> wrote:

> On Sat, Nov 20, 2021 at 6:56 AM Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > On Thu, 18 Nov 2021 23:23:39 -0800 Christoph Hellwig <hch@infradead.org> wrote:
> >
> > > On Fri, Nov 19, 2021 at 12:11:04PM +0800, Muchun Song wrote:
> > > > +
> > > > +/*
> > > > + * Obtain the private data passed by user through proc_create_data() or
> > > > + * related.
> > > > + */
> > > > +static inline void *pde_data(const struct inode *inode)
> > > > +{
> > > > +   return inode->i_private;
> > > > +}
> > > > +
> > > > +#define PDE_DATA(i)        pde_data(i)
> > >
> > > What is the point of pde_data?
> >
> > It's a regular old C function, hence should be in lower case.
> >
> > I assume the upper case thing is a holdover from when it was
> > implemented as a macro.
> >
> > >  If we really think changing to lower
> > > case is worth it (I don't think so, using upper case for getting at
> > > private data is a common idiom in file systems),
> >
> > It is?  How odd.
> >
> > I find the upper-case thing to be actively misleading.  It's mildly
> > surprising to discover that it's actually a plain old C function.
> >
> > > we can just do that
> > > scripted in one go.
> >
> > Yes, I'd like to see a followup patch which converts the current
> > PDE_DATA() callsites.
> >
> 
> You mean replace all PDE_DATA with pde_data in another patch?

That is indeed what I meant.