diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/device.rs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index b538c39982a6..82e46b37e814 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -504,7 +504,11 @@ pub struct Normal; /// callback it appears in. It is intended to be used for synchronization purposes. Bus device /// implementations can implement methods for [`Device<Core>`], such that they can only be called /// from bus callbacks. -pub struct Core<'a>(PhantomData<&'a ()>); +/// +/// The lifetime `'a` is for "lifetime branding" purpose. Callbacks need to polymorphic over this +/// lifetime so the `&'bound Device<Core<'_>>` provided to them cannot outlive the scope of the +/// function. For this reason, it needs to be invariant. +pub struct Core<'a>(PhantomData<fn(&'a ()) -> &'a ()>); /// Semantically the same as [`Core`], but reserved for internal usage of the corresponding bus /// abstraction. @@ -515,7 +519,9 @@ pub struct Core<'a>(PhantomData<&'a ()>); /// /// This context mainly exists to share generic [`Device`] infrastructure that should only be called /// from bus callbacks with bus abstractions, but without making them accessible for drivers. -pub struct CoreInternal<'a>(PhantomData<&'a ()>); +/// +/// Lifetime `'a` is invariant for the same reason as [`Core`]. +pub struct CoreInternal<'a>(PhantomData<fn(&'a ()) -> &'a ()>); /// Semantically the same as [`Bound`], but reserved for internal usage of the corresponding bus /// abstraction. |