[PATCH v7 0/2] Rust support for mm_struct, vm_area_struct, and mmap for miscdevice

[Alice Ryhl <aliceryhl@google.com>]

The first patch introduces mm_struct and vm_area_struct abstractions,
and the second patch uses them for miscdevice.

This updates the vm_area_struct support to use the approach we discussed
at LPC where there are three different types depending on the kind of
access you have to the vma. You either have read access, write access,
or you are initializing it. Each case allows a larger set of operations
on the vma.

The first patch in this series depends on vfs.rust.file for
NotThreadSafe. The second patch in this series depends on char-misc-next
for the base miscdevice implementation.

---
Changes in v7:
- Make the mmap read/write lock guards respect strict owner semantics.
- Link to v6: https://lore.kernel.org/r/20241010-vma-v6-0-d89039b6f573@google.com

Changes in v6:
- Introduce VmArea{Ref,Mut,New} distinction.
- Add a second patchset for miscdevice.
- Rebase on char-misc-next (currently on v6.12-rc2).
- Link to v5: https://lore.kernel.org/r/20240806-vma-v5-1-04018f05de2b@google.com

Changes in v5:
- Rename VmArea::from_raw_vma to from_raw.
- Use Pin for mutable VmArea references.
- Go through `ARef::from` in `mmgrab_current`.
- Link to v4: https://lore.kernel.org/r/20240802-vma-v4-1-091a87058a43@google.com

Changes in v4:
- Pull out ARef::into_raw into a separate patch.
- Update invariants and struct documentation.
- Rename from_raw_mm to from_raw.
- Link to v3: https://lore.kernel.org/r/20240801-vma-v3-1-db6c1c0afda9@google.com

Changes in v3:
- Reorder entries in mm.rs.
- Use ARef for mmput_async helper.
- Clarify that VmArea requires you to hold the mmap read or write lock.
- Link to v2: https://lore.kernel.org/r/20240727-vma-v2-1-ab3e5927dc3a@google.com

Changes in v2:
- mm.rs is redesigned from scratch making use of AsRef
- Add notes about whether destructors may sleep
- Rename Area to VmArea
- Link to v1: https://lore.kernel.org/r/20240723-vma-v1-1-32ad5a0118ee@google.com

---
Alice Ryhl (2):
      rust: mm: add abstractions for mm_struct and vm_area_struct
      rust: miscdevice: add mmap support

 rust/helpers/helpers.c    |   1 +
 rust/helpers/mm.c         |  55 +++++++
 rust/kernel/lib.rs        |   1 +
 rust/kernel/miscdevice.rs |  24 ++++
 rust/kernel/mm.rs         | 357 ++++++++++++++++++++++++++++++++++++++++++++++
 rust/kernel/mm/virt.rs    | 264 ++++++++++++++++++++++++++++++++++
 6 files changed, 702 insertions(+)
---
base-commit: 2d424646119f28780f3963811025c05ea848b85f
change-id: 20240723-vma-f80119f9fb35

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