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From: Alice Ryhl <aliceryhl@google.com>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: "Miguel Ojeda" <ojeda@kernel.org>,
	"Matthew Wilcox" <willy@infradead.org>,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Kees Cook" <keescook@chromium.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Wedson Almeida Filho" <wedsonaf@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	"Andreas Hindborg" <a.hindborg@samsung.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Arve Hjønnevåg" <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>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Trevor Gross" <tmgross@umich.edu>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	rust-for-linux@vger.kernel.org,
	"Christian Brauner" <brauner@kernel.org>
Subject: Re: [PATCH v6 1/4] rust: uaccess: add userspace pointers
Date: Fri, 19 Apr 2024 20:12:24 +0200	[thread overview]
Message-ID: <CAH5fLgh0rFMQcAA4a=Vk8uEkyHP455KeihR-2BkkOpgHS6teKA@mail.gmail.com> (raw)
In-Reply-To: <ZiKltinLGvKlBivm@boqun-archlinux>

On Fri, Apr 19, 2024 at 7:11 PM Boqun Feng <boqun.feng@gmail.com> wrote:
>
> On Thu, Apr 18, 2024 at 08:59:17AM +0000, Alice Ryhl wrote:
> [...]
> > +    /// Reads the entirety of the user slice, appending it to the end of the provided buffer.
> > +    ///
> > +    /// Fails with `EFAULT` if the read happens on a bad address.
> > +    pub fn read_all(mut self, buf: &mut Vec<u8>, flags: Flags) -> Result {
> > +        let len = self.length;
> > +        buf.reserve(len, flags)?;
>
> (Reportedy by Miguel)
>
> When compile with `make rusttest`, kernel crate is compiled as userspace
> program, so we need to explicitly pick where the `reserve` comes from
> (Vec or VecExt), the current version will hit the following error:
>
>         error[E0061]: this method takes 1 argument but 2 arguments were supplied
>            --> rust/kernel/uaccess.rs:296:13
>             |
>         296 |         buf.reserve(len, flags)?;
>             |             ^^^^^^^    -------
>             |                        | |
>             |                        | unexpected argument of type `Flags`
>             |                        help: remove the extra argument
>             |
>         note: method defined here
>            --> /home/boqun/linux-rust/rust/test/sysroot/lib/rustlib/src/rust/library/alloc/src/vec/mod.rs:910:12
>             |
>         910 |     pub fn reserve(&mut self, additional: usize) {
>             |            ^^^^^^^
>
>         error[E0277]: the `?` operator can only be applied to values that implement `Try`
>            --> rust/kernel/uaccess.rs:296:9
>             |
>         296 |         buf.reserve(len, flags)?;
>             |         ^^^^^^^^^^^^^^^^^^^^^^^^ the `?` operator cannot be applied to type `()`
>             |
>             = help: the trait `Try` is not implemented for `()`
>
>         error: aborting due to 2 previous errors
>
>         Some errors have detailed explanations: E0061, E0277.
>         For more information about an error, try `rustc --explain E0061`.
>
> and we need to the following fix
>
> diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs
> index 39481e374c40..80f7e7ca2f5e 100644
> --- a/rust/kernel/uaccess.rs
> +++ b/rust/kernel/uaccess.rs
> @@ -293,7 +293,7 @@ pub fn read<T: FromBytes>(&mut self) -> Result<T> {
>      /// Fails with `EFAULT` if the read happens on a bad address.
>      pub fn read_all(mut self, buf: &mut Vec<u8>, flags: Flags) -> Result {
>          let len = self.length;
> -        buf.reserve(len, flags)?;
> +        VecExt::<u8>::reserve(buf, len, flags)?;
>
>          // The call to `try_reserve` was successful, so the spare capacity is at least `len` bytes
>          // long.

I'm sorry, what? This seems like a problem with `make rusttest`.

Alice

  reply	other threads:[~2024-04-19 18:12 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-18  8:59 [PATCH v6 0/4] Memory management patches needed by Rust Binder Alice Ryhl
2024-04-18  8:59 ` [PATCH v6 1/4] rust: uaccess: add userspace pointers Alice Ryhl
2024-04-19 17:11   ` Boqun Feng
2024-04-19 18:12     ` Alice Ryhl [this message]
2024-04-18  8:59 ` [PATCH v6 2/4] uaccess: always export _copy_[from|to]_user with CONFIG_RUST Alice Ryhl
2024-05-14 17:27   ` Andrew Morton
2024-05-15  7:34     ` Arnd Bergmann
2024-04-18  8:59 ` [PATCH v6 3/4] rust: uaccess: add typed accessors for userspace pointers Alice Ryhl
2024-04-18 13:01   ` Benno Lossin
2024-04-18 13:17     ` Alice Ryhl
2024-04-18 16:23       ` Benno Lossin
2024-04-18 17:19         ` Boqun Feng
2024-04-18 19:35           ` Alice Ryhl
2024-04-18 20:01             ` Boqun Feng
2024-04-18 17:52     ` Trevor Gross
2024-04-25 16:13   ` Gary Guo
2024-04-26  7:13     ` Alice Ryhl
2024-04-18  8:59 ` [PATCH v6 4/4] rust: add abstraction for `struct page` Alice Ryhl
2024-04-18 18:52   ` Boqun Feng
2024-04-18 22:08     ` Benno Lossin
2024-04-18 22:56       ` Boqun Feng
2024-04-18 23:04         ` Boqun Feng
2024-04-19  8:36           ` Benno Lossin
2024-04-19 17:23             ` Boqun Feng
2024-04-19 19:24               ` Benno Lossin
2024-04-19 19:35                 ` Boqun Feng
2024-04-25 16:20         ` Gary Guo

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