diff options
| -rw-r--r-- | rust/kernel/drm/device.rs | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index eb8146ea1c98..f5342de190f4 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -79,6 +79,9 @@ macro_rules! drm_legacy_fields { /// - [`Normal`]: The general-purpose, reference-counted context. A [`Device`] in this context may /// or may not be registered with userspace. /// - [`Registered`]: The device has been registered with userspace at some point. +/// +/// `Device<T, Registered>` dereferences to `Device<T>` ([`Normal`]), so any method available on a +/// [`Normal`] device is also available on a [`Registered`] one. pub trait DeviceContext: Sealed + Send + Sync + 'static {} /// The general-purpose, reference-counted [`DeviceContext`]. @@ -320,7 +323,7 @@ impl<T: drm::Driver, C: DeviceContext> Device<T, C> { } } -impl<T: drm::Driver, C: DeviceContext> Deref for Device<T, C> { +impl<T: drm::Driver> Deref for Device<T> { type Target = T::Data; fn deref(&self) -> &Self::Target { @@ -328,6 +331,17 @@ impl<T: drm::Driver, C: DeviceContext> Deref for Device<T, C> { } } +impl<T: drm::Driver> Deref for Device<T, Registered> { + type Target = Device<T>; + + #[inline] + fn deref(&self) -> &Self::Target { + // SAFETY: The caller holds a `Device<T, Registered>`, which guarantees all invariants + // of the weaker `Normal` context. + unsafe { self.assume_ctx() } + } +} + // SAFETY: DRM device objects are always reference counted and the get/put functions // satisfy the requirements. unsafe impl<T: drm::Driver> AlwaysRefCounted for Device<T> { |