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AJvYcCU+zqarBVriihrSWTBMhx25dzVvtnmPByubyDZYsa3pI61lVrXZpVit5YqKx7l9L+qVWE6UFRbMxrYQTRc=@vger.kernel.org X-Gm-Message-State: AOJu0Yz0kzQDfvM32V98Fgs+Cu+dmzcUpKgzslga2i+Du/xC6RdkPUCs DTN6+F+5PCpMmydixZgzvyXUTOf/wYly3S0/nJY8EkKFY8XTr7cfcIWBM7PO71juEag/nmLMiEX AT8Su1YSgWfq67VphFjYUvSSehg== X-Google-Smtp-Source: AGHT+IHcfJR1o5/SgW7SusAyBpFPhf8oQEmKCsMNeMnl/O4RPVhDd3fZEZ5wBk57GJl19qVgKFljWCgGGjDoMSQ0VXQ= X-Received: from mattgilbride.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:2ac5]) (user=mattgilbride job=sendgmr) by 2002:a25:b11e:0:b0:e11:5c41:54e2 with SMTP id 3f1490d57ef6-e17a38b7fe3mr191276.0.1724344681870; Thu, 22 Aug 2024 09:38:01 -0700 (PDT) Date: Thu, 22 Aug 2024 16:37:54 +0000 In-Reply-To: <20240822-b4-rbtree-v12-0-014561758a57@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240822-b4-rbtree-v12-0-014561758a57@google.com> X-Mailer: b4 0.13.0 Message-ID: <20240822-b4-rbtree-v12-2-014561758a57@google.com> Subject: [PATCH v12 2/5] 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 Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng 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 51c53a25bc7d..29e7a0795266 100644 --- a/rust/kernel/rbtree.rs +++ b/rust/kernel/rbtree.rs @@ -42,14 +42,30 @@ /// 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. @@ -57,9 +73,11 @@ /// /// // 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. @@ -67,9 +85,10 @@ /// /// // 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>(()) @@ -109,9 +128,11 @@ /// /// // 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. @@ -119,9 +140,10 @@ /// /// // 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. @@ -133,9 +155,11 @@ /// /// // 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 2.46.0.184.g6999bdac58-goog