[PATCH v2 0/2] Add Opaque::cast_from

From: Alice Ryhl
Date: Tue Jun 24 2025 - 11:37:54 EST


Since commit b20fbbc08a36 ("rust: check type of `$ptr` in
`container_of!`") we have enforced that the field pointer passed to
container_of! must match the declared field. This caused mismatches when
using a pointer to bindings::x for fields of type Opaque<bindings::x>.

This situation encourages the user to simply pass field.cast() to the
container_of! macro, but this is not great because you might
accidentally pass a *mut bindings::y when the field type is
Opaque<bindings::x>, which would be wrong.

To help catch this kind of mistake, add a new Opaque::cast_from that
wraps a raw pointer in Opaque without changing the inner type. Also
rename raw_get() to cast_into() for naming consistency.

Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
---
Changes in v2:
- Use new naming, and rename raw_get().
- Link to v1: https://lore.kernel.org/r/20250617-opaque-from-raw-v1-1-a2e99efa3ba2@xxxxxxxxxx

---
Alice Ryhl (2):
rust: types: add Opaque::cast_from
rust: types: rename Opaque::raw_get to cast_into

rust/kernel/configfs.rs | 2 +-
rust/kernel/drm/device.rs | 4 +---
rust/kernel/drm/gem/mod.rs | 4 +---
rust/kernel/init.rs | 6 +++---
rust/kernel/lib.rs | 7 +++++++
rust/kernel/list.rs | 2 +-
rust/kernel/list/impl_list_item_mod.rs | 4 ++--
rust/kernel/time/hrtimer.rs | 4 ++--
rust/kernel/types.rs | 11 ++++++++---
rust/kernel/workqueue.rs | 2 +-
10 files changed, 27 insertions(+), 19 deletions(-)
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250617-opaque-from-raw-ac5b8ef6faa2

Best regards,
--
Alice Ryhl <aliceryhl@xxxxxxxxxx>