From: Gary Guo <gary@garyguo.net>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: "Benno Lossin" <benno.lossin@proton.me>,
"Alice Ryhl" <aliceryhl@google.com>,
"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>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"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 4/4] rust: add abstraction for `struct page`
Date: Thu, 25 Apr 2024 17:20:18 +0100 [thread overview]
Message-ID: <20240425172018.015e1afd@eugeo> (raw)
In-Reply-To: <ZiGlC5AtRRikE1AI@boqun-archlinux>
On Thu, 18 Apr 2024 15:56:11 -0700
Boqun Feng <boqun.feng@gmail.com> wrote:
> Hmm.. here is the thing, having `&UnsafeCell<[u8]>` means having a `*mut
> [u8]>`, and it should always be safe to get a "length" of `*mut [u8]`,
> right? I haven't found any method doing that, but the length should be
> just a part of fat pointer, so I think getting that is a defined
> behavior. But maybe I'm missing something.
You can just use `unsafe_cell.get().len()`. `len` method exists on
raw slice pointers, gated by the `slice_ptr_len` feature, which will
be stable in 1.79.0.
Best,
Gary
prev parent reply other threads:[~2024-04-25 16:20 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
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 [this message]
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