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AJvYcCWMpj69yAoEjpApHhQNwmLinZIIABgIdBkdzIEee6znQNrPQw2/iwx7PQu4QVDSzID8DyLeXWq8oofVtnZNwimUnudvMU9ciQxcz9tW X-Gm-Message-State: AOJu0YzH+K0t1qbD4B0c+Lxrp4WV607b8MKilbfPkusxFLVJmntqrxwp +OhPpMttefZhVAnWeZpfT9qO8RAdjh2bTWEE1/Ecb50b2xjP8CK4IBFJ43aCmuba8tz1ojzrGrB giR0uOkPZhDSRxvyK6tPZKH4LGA== X-Google-Smtp-Source: AGHT+IFsKSJand81HJsB482IL+bVTcDYlp8FOZxBQTJoHPmeT261LBWcO7/EdrsYf/ej/U/w4aLjjy6B6V84Yo8Yke0= X-Received: from mattgilbride.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:2ac5]) (user=mattgilbride job=sendgmr) by 2002:a05:620a:3b16:b0:79f:8aa:a85a with SMTP id af79cd13be357-79f19a1fdbamr1722285a.9.1720714873681; Thu, 11 Jul 2024 09:21:13 -0700 (PDT) Date: Thu, 11 Jul 2024 16:20:59 +0000 In-Reply-To: <20240711-b4-rbtree-v6-0-14bef1a8cdba@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240711-b4-rbtree-v6-0-14bef1a8cdba@google.com> X-Mailer: b4 0.13.0 Message-ID: <20240711-b4-rbtree-v6-3-14bef1a8cdba@google.com> Subject: [PATCH v6 3/6] rust: rbtree: add iterator From: Matt Gilbride To: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Andreas Hindborg , Alice Ryhl , Greg Kroah-Hartman , "=?utf-8?q?Arve_Hj=C3=B8nnev=C3=A5g?=" , Todd Kjos , Martijn Coenen , Joel Fernandes , Carlos Llamas , Suren Baghdasaryan , Christian Brauner Cc: Rob Landley , Davidlohr Bueso , Michel Lespinasse , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Matt Gilbride Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Wedson Almeida Filho - Add Iterator implementation for `RBTree`, allowing iteration over (key, value) pairs in key order. - Add individual `keys()` and `values()` functions to iterate over keys or values alone. - Update doctests to use iteration instead of explicitly getting items. Iteration is needed by the binder driver to enumerate all values in a tree for oneway spam detection [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-17-08b= a9197f637@google.com/ [1] Signed-off-by: Wedson Almeida Filho Reviewed-by: Alice Ryhl Tested-by: Alice Ryhl Signed-off-by: Matt Gilbride --- rust/kernel/rbtree.rs | 130 +++++++++++++++++++++++++++++++++++++++++++---= ---- 1 file changed, 112 insertions(+), 18 deletions(-) diff --git a/rust/kernel/rbtree.rs b/rust/kernel/rbtree.rs index a515bfa80113..40db6d3e732b 100644 --- a/rust/kernel/rbtree.rs +++ b/rust/kernel/rbtree.rs @@ -47,14 +47,30 @@ /// assert_eq!(tree.get(&30).unwrap(), &300); /// } /// +/// // Iterate over the nodes we just inserted. +/// { +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &100)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert_eq!(iter.next().unwrap(), (&30, &300)); +/// assert!(iter.next().is_none()); +/// } +/// +/// // Print all elements. +/// for (key, value) in &tree { +/// pr_info!("{} =3D {}\n", key, value); +/// } +/// /// // Replace one of the elements. /// tree.try_create_and_insert(10, 1000, flags::GFP_KERNEL)?; /// /// // Check that the tree reflects the replacement. /// { -/// assert_eq!(tree.get(&10).unwrap(), &1000); -/// assert_eq!(tree.get(&20).unwrap(), &200); -/// assert_eq!(tree.get(&30).unwrap(), &300); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &1000)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert_eq!(iter.next().unwrap(), (&30, &300)); +/// assert!(iter.next().is_none()); /// } /// /// // Change the value of one of the elements. @@ -62,9 +78,11 @@ /// /// // Check that the tree reflects the update. /// { -/// assert_eq!(tree.get(&10).unwrap(), &1000); -/// assert_eq!(tree.get(&20).unwrap(), &200); -/// assert_eq!(tree.get(&30).unwrap(), &3000); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &1000)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert_eq!(iter.next().unwrap(), (&30, &3000)); +/// assert!(iter.next().is_none()); /// } /// /// // Remove an element. @@ -72,9 +90,10 @@ /// /// // Check that the tree reflects the removal. /// { -/// assert_eq!(tree.get(&10), None); -/// assert_eq!(tree.get(&20).unwrap(), &200); -/// assert_eq!(tree.get(&30).unwrap(), &3000); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert_eq!(iter.next().unwrap(), (&30, &3000)); +/// assert!(iter.next().is_none()); /// } /// /// # Ok::<(), Error>(()) @@ -114,9 +133,11 @@ /// /// // Check the nodes we just inserted. /// { -/// assert_eq!(tree.get(&10).unwrap(), &100); -/// assert_eq!(tree.get(&20).unwrap(), &200); -/// assert_eq!(tree.get(&30).unwrap(), &300); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &100)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert_eq!(iter.next().unwrap(), (&30, &300)); +/// assert!(iter.next().is_none()); /// } /// /// // Remove a node, getting back ownership of it. @@ -124,9 +145,10 @@ /// /// // Check that the tree reflects the removal. /// { -/// assert_eq!(tree.get(&10).unwrap(), &100); -/// assert_eq!(tree.get(&20).unwrap(), &200); -/// assert_eq!(tree.get(&30), None); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &100)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert!(iter.next().is_none()); /// } /// /// // Create a preallocated reservation that we can re-use later. @@ -138,9 +160,11 @@ /// /// // Check that the tree reflect the new insertion. /// { -/// assert_eq!(tree.get(&10).unwrap(), &100); -/// assert_eq!(tree.get(&15).unwrap(), &150); -/// assert_eq!(tree.get(&20).unwrap(), &200); +/// let mut iter =3D tree.iter(); +/// assert_eq!(iter.next().unwrap(), (&10, &100)); +/// assert_eq!(iter.next().unwrap(), (&15, &150)); +/// assert_eq!(iter.next().unwrap(), (&20, &200)); +/// assert!(iter.next().is_none()); /// } /// /// # Ok::<(), Error>(()) @@ -167,6 +191,26 @@ pub fn new() -> Self { _p: PhantomData, } } + + /// Returns an iterator over the tree nodes, sorted by key. + pub fn iter(&self) -> Iter<'_, K, V> { + // INVARIANT: `bindings::rb_first` returns a valid pointer to a tr= ee node given a valid pointer to a tree root. + Iter { + _tree: PhantomData, + // SAFETY: `self.root` is a valid pointer to the tree root. + next: unsafe { bindings::rb_first(&self.root) }, + } + } + + /// Returns an iterator over the keys of the nodes in the tree, in sor= ted order. + pub fn keys(&self) -> impl Iterator { + self.iter().map(|(k, _)| k) + } + + /// Returns an iterator over the values of the nodes in the tree, sort= ed by key. + pub fn values(&self) -> impl Iterator { + self.iter().map(|(_, v)| v) + } } =20 impl RBTree @@ -358,6 +402,56 @@ fn drop(&mut self) { } } =20 +impl<'a, K, V> IntoIterator for &'a RBTree { + type Item =3D (&'a K, &'a V); + type IntoIter =3D Iter<'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 Iter<'a, K, V> { + _tree: PhantomData<&'a RBTree>, + next: *mut bindings::rb_node, +} + +// SAFETY: The [`Iter`] gives out immutable references to K and V, so it h= as the same +// thread safety requirements as immutable references. +unsafe impl<'a, K: Sync, V: Sync> Send for Iter<'a, K, V> {} + +// SAFETY: The [`Iter`] gives out immutable references to K and V, so it h= as the same +// thread safety requirements as immutable references. +unsafe impl<'a, K: Sync, V: Sync> Sync for Iter<'a, K, V> {} + +impl<'a, K, V> Iterator for Iter<'a, K, V> { + type Item =3D (&'a K, &'a V); + + fn next(&mut self) -> Option { + if self.next.is_null() { + return None; + } + + // SAFETY: By the type invariant of `Iter`, `self.next` is a valid= node in an `RBTree`, + // and by the type invariant of `RBTree`, all nodes point to the l= inks field of `Node` objects. + let cur =3D unsafe { container_of!(self.next, Node, links) }; + + // SAFETY: `self.next` is a valid tree node by the type invariants. + self.next =3D unsafe { bindings::rb_next(self.next) }; + + // SAFETY: By the same reasoning above, it is safe to dereference = the node. Additionally, + // it is ok to return a reference to members because the iterator = must outlive it. + Some(unsafe { (&(*cur).key, &(*cur).value) }) + } +} + /// A memory reservation for a red-black tree node. /// /// --=20 2.45.2.803.g4e1b14247a-goog