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Date:   Thu, 30 Nov 2023 07:25:01 -0800
From:   Boqun Feng <boqun.feng@gmail.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Alice Ryhl <aliceryhl@google.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Gary Guo <gary@garyguo.net>,
        =?iso-8859-1?Q?Bj=F6rn?= Roy Baron <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        Andreas Hindborg <a.hindborg@samsung.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arve =?iso-8859-1?B?SGr4bm5lduVn?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Carlos Llamas <cmllamas@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Kees Cook <keescook@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Daniel Xu <dxu@dxuuu.xyz>, linux-kernel@vger.kernel.org,
        rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Josh Triplett <josh@joshtriplett.org>
Subject: Re: [PATCH 1/7] rust: file: add Rust abstraction for `struct file`
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On Thu, Nov 30, 2023 at 11:42:26AM +0100, Peter Zijlstra wrote:
> On Wed, Nov 29, 2023 at 09:08:14AM -0800, Boqun Feng wrote:
> 
> > But but but, I then realized we have asm goto in C but Rust doesn't
> > support them, and I haven't thought through how hard tht would be..
> 
> You're kidding right?
> 

I'm not, but I've found this:

	https://github.com/Amanieu/rfcs/blob/inline-asm/text/0000-inline-asm.md#asm-goto

seems to me, the plan for this is something like below:

	asm!(
		"cmp {}, 42",
		"jeq {}",
		in(reg) val,
		label { println!("a"); },
		fallthrough { println!("b"); }
    	);

But it's not implemented yet. Cc Josh in case that he knows more about
this.

Regards,
Boqun

> I thought we *finally* deprecated all compilers that didn't support
> asm-goto and x86 now mandates asm-goto to build, and then this toy
> language comes around ?
> 
> What a load of crap ...