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Date: Thu, 25 Apr 2024 21:56:54 +0000
To: Matt Gilbride <mattgilbride@google.com>, 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>, Andreas Hindborg <a.hindborg@samsung.com>, Alice Ryhl <aliceryhl@google.com>, 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>, Christian Brauner <brauner@kernel.org>
From: Benno Lossin <benno.lossin@proton.me>
Cc: Rob Landley <rob@landley.net>, Davidlohr Bueso <dave@stgolabs.net>, Michel Lespinasse <michel@lespinasse.org>, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/5] rust: rbtree: add `RBTreeIterator`
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References: <20240418-b4-rbtree-v3-0-323e134390ce@google.com> <20240418-b4-rbtree-v3-2-323e134390ce@google.com> <ba946689-d10b-4752-989f-4c6404d7ee55@proton.me>
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On 25.04.24 23:45, Benno Lossin wrote:
> On 18.04.24 16:15, Matt Gilbride wrote:
>> @@ -373,6 +416,56 @@ fn drop(&mut self) {
>>       }
>>   }
>>
>> +impl<'a, K, V> IntoIterator for &'a RBTree<K, V> {
>> +    type Item =3D (&'a K, &'a V);
>> +    type IntoIter =3D RBTreeIterator<'a, K, V>;
>> +
>> +    fn into_iter(self) -> Self::IntoIter {
>> +        self.iter()
>> +    }
>> +}
>> +
>> +/// An iterator over the nodes of a [`RBTree`].
>> +///
>> +/// Instances are created by calling [`RBTree::iter`].
>> +///
>> +/// # Invariants
>> +/// - `self.next` is a valid pointer.
>> +/// - `self.next` points to a node stored inside of a valid `RBTree`.
>> +pub struct RBTreeIterator<'a, K, V> {
>> +    _tree: PhantomData<&'a RBTree<K, V>>,
>> +    next: *mut bindings::rb_node,
>> +}
>> +
>> +// SAFETY: The [`RBTreeIterator`] gives out immutable references to K a=
nd V, so it has the same
>> +// thread safety requirements as immutable references.
>> +unsafe impl<'a, K: Sync, V: Sync> Send for RBTreeIterator<'a, K, V> {}
>=20
> The bounds on `K` and `V` look like typos to me. They should be `Send`
> instead.

Oops, scratch this comment, what you wrote is correct, since we treat
`RBTreeIterator` as `(&K, &V)`.

--=20
Cheers,
Benno