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

Alice Ryhl aliceryhl at google.com
Tue Jun 24 15:27:54 UTC 2025


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 at google.com>
---
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@google.com

---
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 at google.com>



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