From: Benno Lossin <benno.lossin@proton.me>
To: Wedson Almeida Filho <wedsonaf@gmail.com>,
Alice Ryhl <aliceryhl@google.com>
Cc: mathys35.gasnier@gmail.com, "Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Andreas Hindborg" <a.hindborg@samsung.com>,
rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
"Martin Rodriguez Reboredo" <yakoyoku@gmail.com>
Subject: Re: [PATCH v2] rust: locks: Add `get_mut` method to `Lock`
Date: Thu, 15 Feb 2024 20:55:11 +0000 [thread overview]
Message-ID: <ff06ddd4-808a-44fd-9230-f60aa43ec1de@proton.me> (raw)
In-Reply-To: <CANeycqqwGE_eyFSDWkmHCBOMZ6+Ty-XK_hKixMtOYqc9_46j2A@mail.gmail.com>
On 15.02.24 17:50, Wedson Almeida Filho wrote:
> On Mon, 12 Feb 2024 at 11:22, Alice Ryhl <aliceryhl@google.com> wrote:
>>
>> On Mon, Feb 12, 2024 at 3:13 PM Mathys-Gasnier via B4 Relay
>> <devnull+mathys35.gasnier.gmail.com@kernel.org> wrote:
>>> + /// Gets the data contained in the lock
>>> + /// Having a mutable reference to the lock guarantees that no other threads have access to the lock.
>>> + /// Making it safe to get a mutable reference to the lock content.
>>> + pub fn get_mut(&mut self) -> &mut T {
>>> + self.data.get_mut()
>>> + }
>>
>> It's impossible to call this method. You can never have a mutable
>> reference to a Linux mutex because we pin our locks. At most, you can
>> have a Pin<&mut Self>.
>
> Perhaps you meant to say that it's impossible to call this method
> without unsafe blocks? From a `Pin<&mut T>`, we can call
> `get_unchecked_mut` to get an `&mut T`.
That is the wrong way to design this, since it forces an extra
`unsafe` call. Instead this function's receiver type should be
`self: Pin<&mut Self>`.
--
Cheers,
Benno
next prev parent reply other threads:[~2024-02-15 20:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 14:13 [PATCH v2] rust: locks: Add `get_mut` method to `Lock` Mathys-Gasnier via B4 Relay
2024-02-12 14:22 ` Alice Ryhl
2024-02-15 16:50 ` Wedson Almeida Filho
2024-02-15 20:55 ` Benno Lossin [this message]
2024-02-15 16:52 ` Wedson Almeida Filho
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