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References: <20230224-rust-ioctl-v2-1-5325e76a92df@asahilina.net>
Date:   Thu, 23 Mar 2023 13:18:15 +0100
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Asahi Lina" <lina@asahilina.net>,
        "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>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>
Cc:     linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org,
        asahi@lists.linux.dev, Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH v2] rust: ioctl: Add ioctl number manipulation functions
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On Thu, Mar 23, 2023, at 13:08, Asahi Lina wrote:
> Changes in v2:
> - Changed from assert!() to build_assert!() (static_assert!() can't work here)
...
> +/// Build an ioctl number, analogous to the C macro of the same name.
> +const fn _IOC(dir: u32, ty: u32, nr: u32, size: usize) -> u32 {
> +    core::assert!(dir <= bindings::_IOC_DIRMASK);
> +    core::assert!(ty <= bindings::_IOC_TYPEMASK);
> +    core::assert!(nr <= bindings::_IOC_NRMASK);
> +    core::assert!(size <= (bindings::_IOC_SIZEMASK as usize));

Just to make sure: did you actually change it according
to the changelog? It still looks like a runtime assertion
to me, but I don't really understand any rust.

      Arnd