[PATCH v4 0/6] rust: reduce pointer casts, enable related lints

[Tamir Duberstein]

This started with a patch that enabled `clippy::ptr_as_ptr`. Benno
Lossin suggested I also look into `clippy::ptr_cast_constness` and I
discovered `clippy::as_ptr_cast_mut`. This series now enables all 3
lints. It also enables `clippy::as_underscore` which ensures other
pointer casts weren't missed. The first commit reduces the need for
pointer casts and is shared with another series[1].

The final patch also enables pointer provenance lints and fixes
violations. See that commit message for details. The build system
portion of that commit is pretty messy but I couldn't find a better way
to convincingly ensure that these lints were applied globally.
Suggestions would be very welcome.

Link: https://lore.kernel.org/all/20250307-no-offset-v1-0-0c728f63b69c@xxxxxxxxx/ [1]

Signed-off-by: Tamir Duberstein <tamird@xxxxxxxxx>
---
Changes in v4:
- Add missing SoB. (Benno Lossin)
- Use `without_provenance_mut` in alloc. (Boqun Feng)
- Limit strict provenance lints to the `kernel` crate to avoid complex
  logic in the build system. This can be revisited on MSRV >= 1.84.0.
- Rebase on rust-next.
- Link to v3: https://lore.kernel.org/r/20250314-ptr-as-ptr-v3-0-e7ba61048f4a@xxxxxxxxx

Changes in v3:
- Fixed clippy warning in rust/kernel/firmware.rs. (kernel test robot)
  Link: https://lore.kernel.org/all/202503120332.YTCpFEvv-lkp@xxxxxxxxx/
- s/as u64/as bindings::phys_addr_t/g. (Benno Lossin)
- Use strict provenance APIs and enable lints. (Benno Lossin)
- Link to v2: https://lore.kernel.org/r/20250309-ptr-as-ptr-v2-0-25d60ad922b7@xxxxxxxxx

Changes in v2:
- Fixed typo in first commit message.
- Added additional patches, converted to series.
- Link to v1: https://lore.kernel.org/r/20250307-ptr-as-ptr-v1-1-582d06514c98@xxxxxxxxx

---
Tamir Duberstein (6):
      rust: retain pointer mut-ness in `container_of!`
      rust: enable `clippy::ptr_as_ptr` lint
      rust: enable `clippy::ptr_cast_constness` lint
      rust: enable `clippy::as_ptr_cast_mut` lint
      rust: enable `clippy::as_underscore` lint
      rust: use strict provenance APIs

 Makefile                               |  4 +++
 init/Kconfig                           |  3 ++
 rust/bindings/lib.rs                   |  1 +
 rust/kernel/alloc.rs                   |  2 +-
 rust/kernel/alloc/allocator_test.rs    |  2 +-
 rust/kernel/alloc/kvec.rs              |  4 +--
 rust/kernel/block/mq/operations.rs     |  2 +-
 rust/kernel/block/mq/request.rs        |  7 +++--
 rust/kernel/device.rs                  |  5 +--
 rust/kernel/device_id.rs               |  2 +-
 rust/kernel/devres.rs                  | 19 ++++++------
 rust/kernel/error.rs                   |  2 +-
 rust/kernel/firmware.rs                |  3 +-
 rust/kernel/fs/file.rs                 |  2 +-
 rust/kernel/io.rs                      | 16 +++++-----
 rust/kernel/kunit.rs                   | 15 +++++----
 rust/kernel/lib.rs                     | 57 ++++++++++++++++++++++++++++++++--
 rust/kernel/list/impl_list_item_mod.rs |  2 +-
 rust/kernel/miscdevice.rs              |  2 +-
 rust/kernel/of.rs                      |  6 ++--
 rust/kernel/pci.rs                     | 15 +++++----
 rust/kernel/platform.rs                |  6 ++--
 rust/kernel/print.rs                   | 11 +++----
 rust/kernel/rbtree.rs                  | 23 ++++++--------
 rust/kernel/seq_file.rs                |  3 +-
 rust/kernel/str.rs                     | 18 +++++------
 rust/kernel/sync/poll.rs               |  2 +-
 rust/kernel/uaccess.rs                 | 12 ++++---
 rust/kernel/workqueue.rs               | 12 +++----
 rust/uapi/lib.rs                       |  1 +
 30 files changed, 162 insertions(+), 97 deletions(-)
---
base-commit: 2aadc0fc1f85d7a9ed2822ba7ee9f06775eb6d84
change-id: 20250307-ptr-as-ptr-21b1867fc4d4

Best regards,
-- 
Tamir Duberstein <tamird@xxxxxxxxx>