Re: [PATCH v14 0/8] Rust support for mm_struct, vm_area_struct, and mmap

["Liam R. Howlett" <Liam.Howlett@oracle.com>]

* Alice Ryhl <aliceryhl@google.com> [250213 06:04]:
> This updates the vm_area_struct support to use the approach we discussed
> at LPC where there are several different Rust wrappers for
> vm_area_struct depending on the kind of access you have to the vma. Each
> case allows a different set of operations on the vma.
> 
> MM folks, what do you prefer I do for the MAINTAINERS file? Would you
> prefer that I add these files under MEMORY MANAGEMENT, or would you like
> a separate entry similar to the BLOCK LAYER DEVICE DRIVER API [RUST]
> entry? Or something else?
> 
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Acked-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

Thanks for doing this.

> ---
> Changes in v14:
> - Rename VmArea* to Vma* as suggested by Liam.
> - Update a few comments in patch 02.
> - Link to v13: https://lore.kernel.org/r/20250203-vma-v13-0-2b998268a396@google.com
> 
> Changes in v13:
> - Rebase on v6.14-rc1.
> - Remove casts that are now unnecessary due to improved Rust/C integer
>   type mappings.
> - Link to v12: https://lore.kernel.org/r/20250115-vma-v12-0-375099ae017a@google.com
> 
> Changes in v12:
> - Add additional documentation to modules at the top of mm.rs and virt.rs.
> - Explain why the name Mm is used in commit message of patch 1.
> - Expand zap_page_range_single with docs suggested by Lorenzo.
> - Update safety comment in vm_insert_page
> - Mention that VmAreaMixedMap is identical to VmAreaRef except for VM_MIXEDMAP.
> - Update docs for as_mixedmap_vma.
> - Add additional docs for VmAreaNew struct.
> - Rename `get_read` -> `readable` and equivalent for write/exec.
> - Use mut pointers for `from_raw` for VMAs.
> - Update safety comment for fops_mmap.
> - Add additional docs for MiscDevice::mmap.
> - Don't introduce and immediately delete mmgrab_current.
> - Reduce active_pid_ns comment at Andreas's suggestion and link to get_pid_ns.
> - Fix documentation test in rust/kernel/task.rs.
> - Fix warning about unused variables in lock_vma_under_rcu when
>   CONFIG_PER_VMA_LOCK=n.
> - Fix minor typos.
> - Link to v11: https://lore.kernel.org/r/20241211-vma-v11-0-466640428fc3@google.com
> 
> Changes in v11:
> - Add accessor for the vm_mm field of vm_area_struct.
> - Pass the file to MiscDevice::mmap for consistency with
>   https://lore.kernel.org/r/20241210-miscdevice-file-param-v3-1-b2a79b666dc5@google.com
> - Link to v10: https://lore.kernel.org/r/20241129-vma-v10-0-4dfff05ba927@google.com
> 
> Changes in v10:
> - Update docs for `set_io`.
> - Check address in `zap_page_range_single`.
> - Completely redo the last patch.
> - Link to v9: https://lore.kernel.org/r/20241122-vma-v9-0-7127bfcdd54e@google.com
> 
> Changes in v9:
> - Be more explicit about VmAreaNew being used with f_ops->mmap().
> - Point out that clearing VM_MAYWRITE is irreversible.
> - Use __vm_flags to set the flags.
> - Use as_ and into_ prefixes for conversions.
> - Update lock_vma_under_rcu docs and commit msg
> - Mention that VmAreaRef::end is exclusive.
> - Reword docs for zap_page_range_single.
> - Minor fixes to flag docs.
> - Add way to access current->mm without a refcount increment.
> - Link to v8: https://lore.kernel.org/r/20241120-vma-v8-0-eb31425da66b@google.com
> 
> Changes in v8:
> - Split series into more commits to ease review.
> - Improve read locks based on Lorenzo's doc: either the mmap or vma lock
>   can be used.
> - Get rid of mmap write lock because it's possible to avoid the need for
>   it.
> - Do not allow invalid flag combinations on VmAreaNew.
> - Link to v7: https://lore.kernel.org/r/20241014-vma-v7-0-01e32f861195@google.com
> 
> 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 (8):
>       mm: rust: add abstraction for struct mm_struct
>       mm: rust: add vm_area_struct methods that require read access
>       mm: rust: add vm_insert_page
>       mm: rust: add lock_vma_under_rcu
>       mm: rust: add mmput_async support
>       mm: rust: add VmaNew for f_ops->mmap()
>       rust: miscdevice: add mmap support
>       task: rust: rework how current is accessed
> 
>  rust/helpers/helpers.c    |   1 +
>  rust/helpers/mm.c         |  50 +++++
>  rust/kernel/lib.rs        |   1 +
>  rust/kernel/miscdevice.rs |  44 +++++
>  rust/kernel/mm.rs         | 341 +++++++++++++++++++++++++++++++++
>  rust/kernel/mm/virt.rs    | 471 ++++++++++++++++++++++++++++++++++++++++++++++
>  rust/kernel/task.rs       | 247 ++++++++++++------------
>  7 files changed, 1037 insertions(+), 118 deletions(-)
> ---
> base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3
> change-id: 20240723-vma-f80119f9fb35
> 
> Best regards,
> -- 
> Alice Ryhl <aliceryhl@google.com>
>