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Date:   Wed, 29 Nov 2023 17:48:15 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Christian Brauner <brauner@kernel.org>
Cc:     Alice Ryhl <aliceryhl@google.com>, Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@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>,
        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>,
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        Matthew Wilcox <willy@infradead.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
Subject: Re: [PATCH 5/7] rust: file: add `Kuid` wrapper
Message-ID: <20231129164815.GI23596@noisy.programming.kicks-ass.net>
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On Wed, Nov 29, 2023 at 05:28:27PM +0100, Christian Brauner wrote:

> > +pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk,
> > +				  struct pid_namespace *ns)
> > +{
> > +	return task_tgid_nr_ns(tsk, ns);
> > +}
> > +EXPORT_SYMBOL_GPL(rust_helper_task_tgid_nr_ns);
> 
> I'm a bit puzzled by all these rust_helper_*() calls. Can you explain
> why they are needed? Because they are/can be static inlines and that
> somehow doesn't work?

Correct, because Rust can only talk to C ABI, it cannot use C headers.
Bindgen would need to translate the full C headers into valid Rust for
that to work.

I really think the Rust peoples should spend more effort on that,
because you are quite right, all this wrappery is tedious at best.