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Date: Tue, 11 Jun 2024 14:44:09 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Alice Ryhl <aliceryhl@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>, Matthew Wilcox <willy@infradead.org>,
 Al Viro <viro@zeniv.linux.org.uk>, Kees Cook <keescook@chromium.org>, Alex
 Gaynor <alex.gaynor@gmail.com>, Wedson Almeida Filho <wedsonaf@gmail.com>,
 Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
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 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 v7 2/4] uaccess: always export _copy_[from|to]_user with
 CONFIG_RUST
Message-Id: <20240611144409.21840c70387b29eddcf5c2f5@linux-foundation.org>
In-Reply-To: <20240528-alice-mm-v7-2-78222c31b8f4@google.com>
References: <20240528-alice-mm-v7-0-78222c31b8f4@google.com>
	<20240528-alice-mm-v7-2-78222c31b8f4@google.com>
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On Tue, 28 May 2024 14:58:03 +0000 Alice Ryhl <aliceryhl@google.com> wrote:

> Rust code needs to be able to access _copy_from_user and _copy_to_user
> so that it can skip the check_copy_size check in cases where the length
> is known at compile-time, mirroring the logic for when C code will skip
> check_copy_size. To do this, we ensure that exported versions of these
> methods are available when CONFIG_RUST is enabled.
> 
> Alice has verified that this patch passes the CONFIG_TEST_USER_COPY test
> on x86 using the Android cuttlefish emulator.
> 
> ...
>
>  include/linux/uaccess.h | 46 ++++++++++++++++++++++++++++++++--------------
>  lib/usercopy.c          | 30 ++++--------------------------
>  2 files changed, 36 insertions(+), 40 deletions(-)

Acked-by: Andrew Morton <akpm@linux-foundation.org>