Merge tag 'drm-rust-next-2025-11-18' of https://gitlab.freedesktop.org/drm/rust/kernel into drm-next

Cross-subsystem Changes:

Rust
  - Make slice::as_flattened usable on all supported versions of rustc.
  - Add FromBytes::from_bytes_prefix() method.

Core Changes:

  - Update Tyr in MAINTAINERS file.
  - Remove redundant device ptr from Rust GEM object.
  - Change how AlwaysRefCounted is implemented for GEM objects.
  - Add deferred vm_bo cleanup to GPUVM and use it in Panthor.

Driver Changes:

Nova Core
  - Introduction of bitfield! macro, with support for different storage sizes
    and custom visibility.
  - Introduction of safe converters between integer types for which the
    conversion is lossless.
  - GSP initialized up to fully booted state on Ampere.
  - Use more future-proof register for GPU identification.
  - Various simplifications and optimizations.

Nova
  - Select NOVA_CORE.
  - Depend on CONFIG_64BIT.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/aRxtJC0D1pQUepF4@google.com

1 files changed, 16 insertions, 20 deletions

diff --git a/drivers/gpu/nova-core/dma.rs b/drivers/gpu/nova-core/dma.rs
index 94f44bcfd748..7215398969da 100644
--- a/drivers/gpu/nova-core/dma.rs
+++ b/drivers/gpu/nova-core/dma.rs
@@ -2,12 +2,17 @@
 
 //! Simple DMA object wrapper.
 
-use core::ops::{Deref, DerefMut};
-
-use kernel::device;
-use kernel::dma::CoherentAllocation;
-use kernel::page::PAGE_SIZE;
-use kernel::prelude::*;
+use core::ops::{
+    Deref,
+    DerefMut, //
+};
+
+use kernel::{
+    device,
+    dma::CoherentAllocation,
+    page::PAGE_SIZE,
+    prelude::*, //
+};
 
 pub(crate) struct DmaObject {
     dma: CoherentAllocation<u8>,
@@ -25,20 +30,11 @@ impl DmaObject {
     }
 
     pub(crate) fn from_data(dev: &device::Device<device::Bound>, data: &[u8]) -> Result<Self> {
-        Self::new(dev, data.len()).map(|mut dma_obj| {
-            // TODO[COHA]: replace with `CoherentAllocation::write()` once available.
-            // SAFETY:
-            // - `dma_obj`'s size is at least `data.len()`.
-            // - We have just created this object and there is no other user at this stage.
-            unsafe {
-                core::ptr::copy_nonoverlapping(
-                    data.as_ptr(),
-                    dma_obj.dma.start_ptr_mut(),
-                    data.len(),
-                );
-            }
-
-            dma_obj
+        Self::new(dev, data.len()).and_then(|mut dma_obj| {
+            // SAFETY: We have just allocated the DMA memory, we are the only users and
+            // we haven't made the device aware of the handle yet.
+            unsafe { dma_obj.write(data, 0)? }
+            Ok(dma_obj)
         })
     }
 }