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From: Matthew Wilcox <willy@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David Laight" <david.laight.linux@gmail.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Darren Hart" <dvhart@infradead.org>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"André Almeida" <andrealmeid@igalia.com>,
	x86@kernel.org, "Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Christian Brauner" <brauner@kernel.org>,
	"Jan Kara" <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [patch 0/4] uaccess: Provide and use helpers for user masked access
Date: Tue, 19 Aug 2025 03:39:31 +0100	[thread overview]
Message-ID: <aKPj4_-3wNu2v4J2@casper.infradead.org> (raw)
In-Reply-To: <CAHk-=wibAE=yDhWdY7jQ7xvCtbmW5Tjtt_zMJcEzey3xfL=ViA@mail.gmail.com>

On Mon, Aug 18, 2025 at 02:36:31PM -0700, Linus Torvalds wrote:
> I realize some people have grown up being told that "goto is bad". Or
> have been told that exception handling should be baked into the
> language and be asynchronous. Both of those ideas are complete and
> utter garbage, and the result of minds that cannot comprehend reality.
> 
> Asynchronous exceptions are horrific and tend to cause huge
> performance problems (think setjmp()). The Linux kernel exception
> model with explicit exception points is not only "that's how you have
> to do it in C", it's also technically superior.
> 
> And "goto" is fine, as long as you have legible syntax and don't use
> it to generate spaghetti code. Being able to write bad code with goto
> doesn't make 'goto' bad - you can write bad code with *anything*.

Even Dijkstra doesn't argue against using goto for exception handling,

"I remember having read the explicit recommendation to restrict the use
of the go to statement to alarm exits, but I have not been able to trace
it; presumably, it has been made by C.A.R. Hoare."

https://www.cs.utexas.edu/~EWD/transcriptions/EWD02xx/EWD215.html


  parent reply	other threads:[~2025-08-19  2:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-13 15:57 Thomas Gleixner
2025-08-13 15:57 ` [patch 1/4] uaccess: Provide common helpers for masked user access Thomas Gleixner
2025-08-26  7:04   ` Christophe Leroy
2025-09-13 18:01     ` Thomas Gleixner
2025-08-13 15:57 ` [patch 2/4] futex: Convert to get/put_user_masked_u32() Thomas Gleixner
2025-08-13 15:57 ` [patch 3/4] x86/futex: Use user_*_masked_begin() Thomas Gleixner
2025-08-26  7:09   ` Christophe Leroy
2025-08-13 15:57 ` [patch 4/4] select: Use user_read_masked_begin() Thomas Gleixner
2025-08-17 13:49 ` [patch 0/4] uaccess: Provide and use helpers for user masked access David Laight
2025-08-17 14:00   ` Linus Torvalds
2025-08-17 15:29     ` David Laight
2025-08-17 15:36       ` Linus Torvalds
2025-08-18 11:59         ` David Laight
2025-08-18 21:21   ` David Laight
2025-08-18 21:36     ` Linus Torvalds
2025-08-18 22:21       ` Al Viro
2025-08-18 23:00         ` Linus Torvalds
2025-08-19  0:39           ` Al Viro
2025-08-20 23:48             ` Al Viro
2025-08-21  7:45               ` Christian Brauner
2025-08-21 22:49                 ` Al Viro
2025-08-19  2:39       ` Matthew Wilcox [this message]
2025-08-19 21:33       ` David Laight
2025-08-19  4:44     ` Thomas Weißschuh

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