Received-SPF: pass (google.com: domain of linux-kernel+bounces-62164-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Message-ID: <a5f7bf1e-0846-476d-8d21-b816fd3916ca@gmail.com>
Date: Mon, 12 Feb 2024 15:11:41 -0300
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v2 4/4] rust: add abstraction for `struct page`
Content-Language: en-US
To: Alice Ryhl <aliceryhl@google.com>
Cc: 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>,
 Benno Lossin <benno.lossin@proton.me>,
 Andreas Hindborg <a.hindborg@samsung.com>, Kees Cook
 <keescook@chromium.org>, Al Viro <viro@zeniv.linux.org.uk>,
 Andrew Morton <akpm@linux-foundation.org>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 =?UTF-8?Q?Arve_Hj=C3=B8nnev=C3=A5g?= <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>, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org,
 Christian Brauner <brauner@kernel.org>
References: <20240208-alice-mm-v2-0-d821250204a6@google.com>
 <20240208-alice-mm-v2-4-d821250204a6@google.com>
 <d35a656b-b802-4f1e-90d6-7320d61ed818@gmail.com>
 <CAH5fLghM2thHeQifehUDT1b64okVn3sh6Eg_oPxqoK2zU-EJGw@mail.gmail.com>
From: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
In-Reply-To: <CAH5fLghM2thHeQifehUDT1b64okVn3sh6Eg_oPxqoK2zU-EJGw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

On 2/12/24 06:36, Alice Ryhl wrote:
> On Sat, Feb 10, 2024 at 5:23 AM Martin Rodriguez Reboredo
> <yakoyoku@gmail.com> wrote:
>>
>> On 2/8/24 12:47, Alice Ryhl wrote:
>>> [...]
>>> +    /// Maps the page and reads from it into the given buffer.
>>> +    ///
>>> +    /// This method will perform bounds checks on the page offset. If `offset ..
>>> +    /// offset+len` goes outside ot the page, then this call returns `EINVAL`.
>>> +    ///
>>> +    /// # Safety
>>> +    ///
>>> +    /// * Callers must ensure that `dst` is valid for writing `len` bytes.
>>> +    /// * Callers must ensure that this call does not race with a write to the
>>> +    ///   same page that overlaps with this read.
>>
>> This safety section says that a call mustn't race with a page that
>> overlaps this read, hmmmmm.
> 
> Is there a question here?

I've said more like introducing the next point, but if you want to use
`copy_nonoverlapping` then the safety section should mention that both
`src` and `dst` memory areas are forbidden to be overlapping.

> [...]
> I'll use copy_nonoverlapping. Thanks for the suggestion.
> 
> Alice

You're welcome.