Merge tag 'nova-next-v6.16-2025-05-20' of https://gitlab.freedesktop.org/drm/nova into drm-next

Nova changes for v6.16

auxiliary:
  - bus abstractions
  - implementation for driver registration
  - add sample driver

drm:
  - implement __drm_dev_alloc()
  - DRM core infrastructure Rust abstractions
    - device, driver and registration
    - DRM IOCTL
    - DRM File
    - GEM object
  - IntoGEMObject rework
    - generically implement AlwaysRefCounted through IntoGEMObject
    - refactor unsound from_gem_obj() into as_ref()
    - refactor into_gem_obj() into as_raw()

driver-core:
  - merge topic/device-context-2025-04-17 from driver-core tree
  - implement Devres::access()
    - fix: doctest build under `!CONFIG_PCI`
  - accessor for Device::parent()
    - fix: conditionally expect `dead_code` for `parent()`
  - impl TryFrom<&Device> bus devices (PCI, platform)

nova-core:
  - remove completed Vec extentions from task list
  - register auxiliary device for nova-drm
  - derive useful traits for Chipset
  - add missing GA100 chipset
  - take &Device<Bound> in Gpu::new()
  - infrastructure to generate register definitions
  - fix register layout of NV_PMC_BOOT_0
  - move Firmware into own (Rust) module
  - fix: select AUXILIARY_BUS

nova-drm:
  - initial driver skeleton (depends on drm and auxiliary bus
    abstractions)
  - fix: select AUXILIARY_BUS

Rust (dependencies):
  - implement Opaque::zeroed()
  - implement Revocable::try_access_with()
  - implement Revocable::access()

From: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/aCxAf3RqQAXLDhAj@cassiopeiae

1 files changed, 28 insertions, 0 deletions

diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
index 1e5a9d25c21b..db4aa46bb121 100644
--- a/rust/kernel/revocable.rs
+++ b/rust/kernel/revocable.rs
@@ -123,6 +123,34 @@ impl<T> Revocable<T> {
         }
     }
 
+    /// Tries to access the wrapped object and run a closure on it while the guard is held.
+    ///
+    /// This is a convenience method to run short non-sleepable code blocks while ensuring the
+    /// guard is dropped afterwards. [`Self::try_access`] carries the risk that the caller will
+    /// forget to explicitly drop that returned guard before calling sleepable code; this method
+    /// adds an extra safety to make sure it doesn't happen.
+    ///
+    /// Returns [`None`] if the object has been revoked and is therefore no longer accessible, or
+    /// the result of the closure wrapped in [`Some`]. If the closure returns a [`Result`] then the
+    /// return type becomes `Option<Result<>>`, which can be inconvenient. Users are encouraged to
+    /// define their own macro that turns the [`Option`] into a proper error code and flattens the
+    /// inner result into it if it makes sense within their subsystem.
+    pub fn try_access_with<R, F: FnOnce(&T) -> R>(&self, f: F) -> Option<R> {
+        self.try_access().map(|t| f(&*t))
+    }
+
+    /// Directly access the revocable wrapped object.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure this [`Revocable`] instance hasn't been revoked and won't be revoked
+    /// as long as the returned `&T` lives.
+    pub unsafe fn access(&self) -> &T {
+        // SAFETY: By the safety requirement of this function it is guaranteed that
+        // `self.data.get()` is a valid pointer to an instance of `T`.
+        unsafe { &*self.data.get() }
+    }
+
     /// # Safety
     ///
     /// Callers must ensure that there are no more concurrent users of the revocable object.