Merge patch series "ForLt/CovariantForLt split, auxiliary closure API and DevresLt"

Danilo Krummrich <dakr@kernel.org> says:

The ForLt trait currently guarantees covariance, which allows safe
lifetime shortening via cast_ref(). However, some types (e.g. those
containing Mutex<&'bound T>) are invariant over their lifetime parameter
and cannot safely use cast_ref().

This series splits ForLt into two traits:

  - ForLt: base trait for all lifetime-parameterized types, providing
    only the Of<'a> GAT.

  - CovariantForLt: unsafe subtrait that guarantees covariance,
    providing a safe cast_ref() method.

For invariant types, a closure-based API (registration_data_with()) is
added to the auxiliary subsystem. The closure's HRTB prevents the caller
from choosing a concrete lifetime, which would be unsound for invariant
types.

On top of that, this series adds DevresLt<F: ForLt>, a thin wrapper
around Devres<F::Of<'static>> that shortens the stored 'static lifetime
back to the caller's borrow scope. DevresLt provides both closure-based
access (access_with/try_access_with for ForLt types) and direct
reference access (access/try_access for CovariantForLt types).

Also implement ForLt and CovariantForLt for Bar, IoMem and
ExclusiveIoMem, and update their into_devres() methods to return
DevresLt. Provide convenience type aliases DevresBar, DevresIoMem and
DevresExclusiveIoMem.

Link: https://patch.msgid.link/20260626183630.2585057-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index 5738d4ac521b..48380ac15f68 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -15,7 +15,7 @@ use kernel::{
         Atomic,
         Relaxed, //
     },
-    types::ForLt,
+    types::CovariantForLt,
 };
 
 use crate::gpu::Gpu;
@@ -29,7 +29,7 @@ pub(crate) struct NovaCore<'bound> {
     pub(crate) gpu: Gpu<'bound>,
     bar: pci::Bar<'bound, BAR0_SIZE>,
     #[allow(clippy::type_complexity)]
-    _reg: auxiliary::Registration<'bound, ForLt!(())>,
+    _reg: auxiliary::Registration<'bound, CovariantForLt!(())>,
 }
 
 pub(crate) struct NovaCoreDriver;