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Re: [git pull] uaccess-related bits of vfs.git

From Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups linux.kernel
Subject Re: [git pull] uaccess-related bits of vfs.git
Date 2017-05-13 21:10 +0200
Message-ID <tGKAq-7Ln-7@gated-at.bofh.it> (permalink)
References (3 earlier) <tGzbX-8r2-5@gated-at.bofh.it> <tGHVU-5Ze-5@gated-at.bofh.it> <tGIIi-6ye-11@gated-at.bofh.it> <tGIRY-6C1-17@gated-at.bofh.it> <tGJEl-7aE-3@gated-at.bofh.it>
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On Sat, May 13, 2017 at 11:04 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
>
> My point is, this stuff needs looking at.

No.

You don't have a point. I've tried to explain that there's no
performance difference, and there is no way in hell that the current
"__" versions are better.

So what's the point in looking? All you are ever going to come up with
is theoretical "this might" cases.

The only sane forward is to just get rid of them. At that point, you
*may* end up actually noticing something, but if you do, it's not a
"you might" issue.

There's literally no upside to this "needs looking at". There are only
downsides.

And one major downside of your "needs looking at". is this one:

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 24 Mar 2015 10:42:18 -0700
>
> So I'd suggest we should just do a wholesale replacement of
> __copy_to/from_user() with the non-underlined cases. Then, we could
> switch insividual ones back - with reasoning of why they matter, and
> with pointers to how it does access_ok() two lines before.
>
> We should probably even consider looking at __get_user/__put_user().
> Few of them are actually performance-critical.

Look at that date. It's over two years ago. In the intervening two
years, how many of those conversions have happened?

Here's a hint: it's a very very round number.

                 Linus

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Thread

Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 03:10 +0200
  Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 09:00 +0200
    Re: [git pull] uaccess-related bits of vfs.git Adam Borowski <kilobyte@angband.pl> - 2017-05-13 14:10 +0200
      Re: [git pull] uaccess-related bits of vfs.git Brian Gerst <brgerst@gmail.com> - 2017-05-13 15:50 +0200
      Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 18:50 +0200
    Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 18:20 +0200
    Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 18:20 +0200
      Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 19:10 +0200
        Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 19:20 +0200
          Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 20:10 +0200
            Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 20:30 +0200
              Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:20 +0200
                Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:40 +0200
            Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 21:10 +0200
              Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:20 +0200
              Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:00 +0200
                Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:10 +0200
                Re: [git pull] uaccess-related bits of vfs.git Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-13 22:40 +0200
                Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:50 +0200
              Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:40 +0200
                Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 23:00 +0200
                Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 23:30 +0200
        Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 19:20 +0200
      Re: [git pull] uaccess-related bits of vfs.git Ingo Molnar <mingo@kernel.org> - 2017-05-14 20:20 +0200
        Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-14 21:00 +0200

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