[PATCH 0/3] Add Rust abstraction for Maple Trees

[Alice Ryhl <aliceryhl@google.com>]

This will be used in the Tyr driver [1] to allocate from the GPU's VA
space that is not owned by userspace, but by the kernel, for kernel GPU
mappings.

Danilo tells me that in nouveau, the maple tree is used for keeping
track of "VM regions" on top of GPUVM, and that he will most likely end
up doing the same in the Rust Nova driver as well.

These abstractions intentionally do not expose any way to make use of
external locking. You are required to use the internal spinlock. For
now, we do not support loads that only utilize rcu for protection.

This contains some parts taken from Andrew Ballance's RFC [2] from
April. However, it has also been reworked significantly compared to that
RFC taking the use-cases in Tyr into account.

[1]: https://lore.kernel.org/r/20250627-tyr-v1-1-cb5f4c6ced46@collabora.com
[2]: https://lore.kernel.org/r/20250405060154.1550858-1-andrewjballance@gmail.com

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
Alice Ryhl (3):
      rust: maple_tree: add MapleTree
      rust: maple_tree: add MapleTree::lock() and load()
      rust: maple_tree: add MapleTreeAlloc

 MAINTAINERS               |   2 +
 rust/helpers/helpers.c    |   1 +
 rust/helpers/maple_tree.c |  14 ++
 rust/kernel/lib.rs        |   1 +
 rust/kernel/maple_tree.rs | 538 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 556 insertions(+)
---
base-commit: dff64b072708ffef23c117fa1ee1ea59eb417807
change-id: 20250726-maple-tree-1af0803ac524

Best regards,
-- 
Alice Ryhl <aliceryhl@google.com>