rust/helpers.c | 7 + rust/kernel/alloc/box_ext.rs | 24 +- rust/kernel/lib.rs | 1 + rust/kernel/rbtree.rs | 1290 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 1321 insertions(+), 1 deletion(-)
This patchset contains the red-black tree abstractions needed by the Rust implementation of the Binder driver. Binder driver benefits from O(log n) search/insertion/deletion of key/value mappings in various places, including `process.rs` and `range_alloc.rs`. In `range_alloc.rs`, the ability to store and search by a generic key type is also useful. Please see the Rust Binder RFC for usage examples [1]. Note that the `container_of` macro is currently used only by `rbtree` itself. Users of "rust: rbtree: add red-black tree implementation backed by the C version" [PATCH RFC 03/20] rust_binder: add threading support [PATCH RFC 05/20] rust_binder: add nodes and context managers [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: rbtree: add iterator" [PATCH RFC 17/20] rust_binder: add oneway spam detection Users of "rust: rbtree: add mutable iterator" [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: rbtree: add `RBTreeCursor`" [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: rbtree: add RBTree::entry" Not used in the original RFC, but introduced after further code review. See: https://r.android.com/2849906 The Rust Binder RFC addresses the upstream deprecation of red-black tree. Quoted here for convenience: "This RFC uses the kernel's red-black tree for key/value mappings, but we are aware that the red-black tree is deprecated. We did this to make the performance comparison more fair, since C binder also uses rbtree for this. We intend to replace these with XArrays instead. That said, we don't think that XArray is a good fit for the range allocator, and we propose to continue using the red-black tree for the range allocator." Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com/ [1] Signed-off-by: Matt Gilbride <mattgilbride@google.com> --- Changes in v7: - make `RawVacantEntry.rbtree` a raw pointer like `RawVacantEntry.child_field_of_parent`, since the latter can technically point at a field of the former. We prefer that the implementation be explicit about the safety guarantees of both because of the relationship between them. - Link to v6: https://lore.kernel.org/r/20240711-b4-rbtree-v6-0-14bef1a8cdba@google.com Changes in v6: - Minimize usage of `*mut bindings::rb_node`, replacing with `NonNull<bindings::rb_node>`. Specifically, changing `RBTreeCursor.current` to be `NonNull<bindings::rb_node>` and updating the corresponding functions. - Update `RBTreeCursor:to_key_value` helpers to have their own lifetime (they are not instance methods, using a different lifetime than that of the `impl` block they are in makes things more clear. - Fix misplaced semicolon in `cursor_lower_bound`. - Link to v5: https://lore.kernel.org/r/20240606-b4-rbtree-v5-0-96fe1a0e97c0@google.com Changes in v5: - Used `Box::write` in `RBTreeNodeReservation::into_node`, removing unnecessary `unsafe` blocks. - Updated `RBTreeCursor::remove_current` to return the removed node. - Link to v4: https://lore.kernel.org/r/20240603-b4-rbtree-v4-0-308e43d6abfc@google.com Changes in v4: - rebased onto the tip of rust-for-linux/rust-next (97ab3e8eec0ce79d9e265e6c9e4c480492180409) - addressed comments from draft PR on GitHub: https://github.com/Rust-for-Linux/linux/pull/1081 - Link to v3: https://lore.kernel.org/r/20240418-b4-rbtree-v3-0-323e134390ce@google.com Changes in v3: - Address various feedback re: SAFETY and INVARIANT comments from v2. - Update variable naming and add detailed comments for the `RBTree::insert` (later moved to `RBTree::raw_entry`) implementation. - Link to v2: https://lore.kernel.org/r/20240219-b4-rbtree-v2-0-0b113aab330d@google.com Changes in v2: - Update documentation link to the C header file - Use `core::convert::Infallible` in try_reserve_node - Link to v1: https://lore.kernel.org/r/20240205-b4-rbtree-v1-0-995e3eee38c0@google.com --- Alice Ryhl (1): rust: rbtree: add `RBTree::entry` Benno Lossin (1): rust: kernel: add `drop_contents` to `BoxExt` Matt Gilbride (1): rust: rbtree: add `RBTreeCursor` Wedson Almeida Filho (3): rust: rbtree: add red-black tree implementation backed by the C version rust: rbtree: add iterator rust: rbtree: add mutable iterator rust/helpers.c | 7 + rust/kernel/alloc/box_ext.rs | 24 +- rust/kernel/lib.rs | 1 + rust/kernel/rbtree.rs | 1290 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 1321 insertions(+), 1 deletion(-) --- base-commit: 97ab3e8eec0ce79d9e265e6c9e4c480492180409 change-id: 20231205-b4-rbtree-abb1a016f0a0 Best regards, -- Matt Gilbride <mattgilbride@google.com>
On Fri, Jul 26, 2024 at 07:57:39PM +0000, Matt Gilbride wrote: > This patchset contains the red-black tree abstractions needed by the Rust > implementation of the Binder driver. > > Binder driver benefits from O(log n) search/insertion/deletion of > key/value mappings in various places, including `process.rs` and > `range_alloc.rs`. In `range_alloc.rs`, the ability to store and > search by a generic key type is also useful. > > Please see the Rust Binder RFC for usage examples [1]. Note that > the `container_of` macro is currently used only by `rbtree` itself. > > Users of "rust: rbtree: add red-black tree implementation backed by the C version" > [PATCH RFC 03/20] rust_binder: add threading support > [PATCH RFC 05/20] rust_binder: add nodes and context managers > [PATCH RFC 06/20] rust_binder: add oneway transactions > > Users of "rust: rbtree: add iterator" > [PATCH RFC 17/20] rust_binder: add oneway spam detection > > Users of "rust: rbtree: add mutable iterator" > [PATCH RFC 06/20] rust_binder: add oneway transactions > > Users of "rust: rbtree: add `RBTreeCursor`" > [PATCH RFC 06/20] rust_binder: add oneway transactions > > Users of "rust: rbtree: add RBTree::entry" > Not used in the original RFC, but introduced after further > code review. See: https://r.android.com/2849906 > > The Rust Binder RFC addresses the upstream deprecation of red-black > tree. Quoted here for convenience: > > "This RFC uses the kernel's red-black tree for key/value mappings, but we > are aware that the red-black tree is deprecated. We did this to make the > performance comparison more fair, since C binder also uses rbtree for > this. We intend to replace these with XArrays instead. That said, we > don't think that XArray is a good fit for the range allocator, and we > propose to continue using the red-black tree for the range allocator." > > Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com/ [1] > Signed-off-by: Matt Gilbride <mattgilbride@google.com> Thanks! For patch #5, there is a small style issue, which can be fixed by: diff --git a/rust/kernel/rbtree.rs b/rust/kernel/rbtree.rs index f6d5162e46f5..96fd45f9dc52 100644 --- a/rust/kernel/rbtree.rs +++ b/rust/kernel/rbtree.rs @@ -465,9 +465,7 @@ pub fn cursor_lower_bound(&mut self, key: &K) -> Option<RBTreeCursor<'_, K, V>> } } - let Some(best) = best_match else { - return None; - }; + let best = best_match?; // SAFETY: `best` is a non-null node so it is valid by the type invariants. let links = unsafe { addr_of_mut!((*best.as_ptr()).links) }; with that, for the whole series: Reviewed-by: Boqun Feng <boqun.feng@gmail.com> I also put this on rust-dev branch for my own testing purpose (with the above fix applied, and using Benno's version of patch #1 since it's already in rust-dev). Regards, Boqun > --- > Changes in v7: > - make `RawVacantEntry.rbtree` a raw pointer like > `RawVacantEntry.child_field_of_parent`, since the latter can > technically point at a field of the former. We prefer that the > implementation be explicit about the safety guarantees of both because > of the relationship between them. > - Link to v6: https://lore.kernel.org/r/20240711-b4-rbtree-v6-0-14bef1a8cdba@google.com > > Changes in v6: > - Minimize usage of `*mut bindings::rb_node`, replacing with > `NonNull<bindings::rb_node>`. Specifically, changing > `RBTreeCursor.current` to be `NonNull<bindings::rb_node>` and updating > the corresponding functions. > - Update `RBTreeCursor:to_key_value` helpers to have their own lifetime > (they are not instance methods, using a different lifetime than that > of the `impl` block they are in makes things more clear. > - Fix misplaced semicolon in `cursor_lower_bound`. > - Link to v5: https://lore.kernel.org/r/20240606-b4-rbtree-v5-0-96fe1a0e97c0@google.com > > Changes in v5: > - Used `Box::write` in `RBTreeNodeReservation::into_node`, removing > unnecessary `unsafe` blocks. > - Updated `RBTreeCursor::remove_current` to return the removed node. > - Link to v4: https://lore.kernel.org/r/20240603-b4-rbtree-v4-0-308e43d6abfc@google.com > > Changes in v4: > - rebased onto the tip of rust-for-linux/rust-next (97ab3e8eec0ce79d9e265e6c9e4c480492180409) > - addressed comments from draft PR on GitHub: https://github.com/Rust-for-Linux/linux/pull/1081 > - Link to v3: https://lore.kernel.org/r/20240418-b4-rbtree-v3-0-323e134390ce@google.com > > Changes in v3: > - Address various feedback re: SAFETY and INVARIANT comments from v2. > - Update variable naming and add detailed comments for the `RBTree::insert` (later moved to > `RBTree::raw_entry`) implementation. > - Link to v2: https://lore.kernel.org/r/20240219-b4-rbtree-v2-0-0b113aab330d@google.com > > Changes in v2: > - Update documentation link to the C header file > - Use `core::convert::Infallible` in try_reserve_node > - Link to v1: https://lore.kernel.org/r/20240205-b4-rbtree-v1-0-995e3eee38c0@google.com > > --- > Alice Ryhl (1): > rust: rbtree: add `RBTree::entry` > > Benno Lossin (1): > rust: kernel: add `drop_contents` to `BoxExt` > > Matt Gilbride (1): > rust: rbtree: add `RBTreeCursor` > > Wedson Almeida Filho (3): > rust: rbtree: add red-black tree implementation backed by the C version > rust: rbtree: add iterator > rust: rbtree: add mutable iterator > > rust/helpers.c | 7 + > rust/kernel/alloc/box_ext.rs | 24 +- > rust/kernel/lib.rs | 1 + > rust/kernel/rbtree.rs | 1290 ++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 1321 insertions(+), 1 deletion(-) > --- > base-commit: 97ab3e8eec0ce79d9e265e6c9e4c480492180409 > change-id: 20231205-b4-rbtree-abb1a016f0a0 > > Best regards, > -- > Matt Gilbride <mattgilbride@google.com> >
© 2016 - 2024 Red Hat, Inc.