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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 29 Mar 2017 14:24:37 -0700
Message-ID: <CA+55aFyEQ_naUW6Q+qVoBA24bgBh1=2H+V54k501uV2pKFv+nw@mail.gmail.com>
Subject: Re: [RFC][CFT][PATCHSET v1] uaccess unification
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
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        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Chen Liqin <liqin.linux@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Chris Metcalf <cmetcalf@mellanox.com>,
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On Wed, Mar 29, 2017 at 2:03 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> it's not as if having the possibility to inline them
> would really complicate the generic side of things...

I disagree.

I think one of the biggest problems with our current uaccess.h mess is
just how illegible the header files are, and the
INLINE_COPY_{TO,FROM}_USER thing is not helping.

I think it would be much better if the header file just had

 extern unsigned long _copy_from_user(void *, const void __user *,
unsigned long);

and nothing else. No unnecessary noise.

The same goes for things like [__]copy_in_user() - why is that thing
still inlined? If it was a *macro*, it might be useful due to the
might_fault() thing giving the caller information, but that's not even
the case here, so we'd actually be much better off without any of that
inlining stuff. Do it all in lib/usercopy.c, and move the
might_fault() in there too.

                Linus