diff options
| author | Alice Ryhl <aliceryhl@google.com> | 2025-06-24 15:27:55 +0000 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2025-07-15 21:01:48 +0200 |
| commit | 8802e168437840ea0b1d5ca571cd3e95681e9e2b (patch) | |
| tree | 15a8ff5d18ce4eb58e07ac034ee0577634d578d4 /rust/kernel/lib.rs | |
| parent | a68a6bef0e75fb9e5aea1399d8538f4e3584dab1 (diff) | |
rust: types: add Opaque::cast_from
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
update the docs to reflect this as well as some existing users.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250624-opaque-from-raw-v2-1-e4da40bdc59c@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust/kernel/lib.rs')
| -rw-r--r-- | rust/kernel/lib.rs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 6b4774b2b1c3..529ce9074996 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -204,6 +204,13 @@ fn panic(info: &core::panic::PanicInfo<'_>) -> ! { /// Produces a pointer to an object from a pointer to one of its fields. /// +/// If you encounter a type mismatch due to the [`Opaque`] type, then use [`Opaque::raw_get`] or +/// [`Opaque::cast_from`] to resolve the mismatch. +/// +/// [`Opaque`]: crate::types::Opaque +/// [`Opaque::raw_get`]: crate::types::Opaque::raw_get +/// [`Opaque::cast_from`]: crate::types::Opaque::cast_from +/// /// # Safety /// /// The pointer passed to this macro, and the pointer returned by this macro, must both be in |