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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 4 May 2024 10:50:29 -0700
Message-ID: <CAHk-=whz-pFHfC4nNdrBtWs4KOm7Q2d2quHmFFYzz1Dz7d7LnQ@mail.gmail.com>
Subject: Re: [PATCH v3] tty: tty_io: remove hung_up_tty_fops
To: paulmck@kernel.org
Cc: Boqun Feng <boqun.feng@gmail.com>, Marco Elver <elver@google.com>, 
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Dmitry Vyukov <dvyukov@google.com>, 
	syzbot <syzbot+b7c3ba8cdc2f6cf83c21@syzkaller.appspotmail.com>, 
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, 
	Nathan Chancellor <nathan@kernel.org>, Arnd Bergmann <arnd@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>, 
	Jiri Slaby <jirislaby@kernel.org>
Content-Type: text/plain; charset="UTF-8"

On Fri, 3 May 2024 at 22:08, Paul E. McKenney <paulmck@kernel.org> wrote:
>
> You are right, this is going to need some arch-specific code for a few
> of the architectures.  Hey, I was hoping!!!
>
> The compilers do not currently optimize these things, but things appear
> to me to be heading in that direction.

Ok, so it sounds like right now it makes no sense - presumably
__atomic_load_n() doesn't actually generate better code than
READ_ONCE() does as-is, and we have the issue with having to make it
per-architecture anyway.

But maybe in a couple of years we can revisit this when / if it
actually generates better code and is more widely applicable.

            Linus