netdev - RE: [PATCH v2 1/2] fs: Export __receive

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Date:   Tue, 16 Aug 2022 17:29:53 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Kuniyuki Iwashima' <kuniyu@...zon.com>
CC:     "davem@...emloft.net" <davem@...emloft.net>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "tkhai@...ru" <tkhai@...ru>,
        "viro@...iv.linux.org.uk" <viro@...iv.linux.org.uk>
Subject: RE: [PATCH v2 1/2] fs: Export __receive_fd()

From: Kuniyuki Iwashima
> Sent: 16 August 2022 18:15
> 
> From:   David Laight <David.Laight@...LAB.COM>
> Date:   Tue, 16 Aug 2022 08:03:14 +0000
> > From: Kirill Tkhai
> > > Sent: 15 August 2022 22:15
> > >
> > > This is needed to make receive_fd_user() available in modules, and it will be used in next patch.
> > >
> > > Signed-off-by: Kirill Tkhai <tkhai@...ru>
> > > ---
> > > v2: New
> > >  fs/file.c |    1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/fs/file.c b/fs/file.c
> > > index 3bcc1ecc314a..e45d45f1dd45 100644
> > > --- a/fs/file.c
> > > +++ b/fs/file.c
> > > @@ -1181,6 +1181,7 @@ int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
> > >  	__receive_sock(file);
> > >  	return new_fd;
> > >  }
> > > +EXPORT_SYMBOL_GPL(__receive_fd);
> >
> > It doesn't seem right (to me) to be exporting a function
> > with a __ prefix.
> 
> +1.
> Now receive_fd() has inline and it's the problem.
> Can we avoid this by moving receive_fd() in fs/file.c without inline and
> exporting it?

It looks like it is receive_fd_user() that should be made a real
function and then exported.
__receive_fd() can then be static.
The extra function call will be noise - and the compiler may
well either tail-call it or inline different copies of __receive_fd()
into the two callers.

	David

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