On Thu Jun 4, 2026 at 8:24 PM BST, Lyude Paul wrote:
Just a temporary holdover to make locking/unlocking the dma_resv lock much easier.
Signed-off-by: Lyude Paul lyude@redhat.com Co-authored-by: Alexandre Courbot acourbot@nvidia.com Signed-off-by: Alexandre Courbot acourbot@nvidia.com
V17:
- Fix format of commit message title
rust/kernel/drm/gem/shmem.rs | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs index 084b798ce795b..650c34dd8b7a4 100644 --- a/rust/kernel/drm/gem/shmem.rs +++ b/rust/kernel/drm/gem/shmem.rs @@ -30,7 +30,10 @@ Deref, DerefMut, // },
- ptr::NonNull, //
- ptr::{
self,NonNull, //- },
}; use gem::{ BaseObjectPrivate, @@ -244,3 +247,29 @@ impl<T: DriverObject, C: DeviceContext> driver::AllocImpl for Object<T, C> { dumb_map_offset: None, }; }
+/// Private helper-type for holding the `dma_resv` object for a GEM shmem object. +/// +/// When this is dropped, the `dma_resv` lock is dropped as well. +/// +// TODO: This should be replace with a WwMutex equivalent once we have such bindings in the kernel. +struct DmaResvGuard<'a, T: DriverObject, C: DeviceContext = Registered>(&'a Object<T, C>);
+impl<'a, T: DriverObject, C: DeviceContext> DmaResvGuard<'a, T, C> {
- #[inline(always)]
Why `always` here?
Best, Gary
- #[expect(unused)]
- fn new(obj: &'a Object<T, C>) -> Self {
// SAFETY: This lock is initialized throughout the lifetime of `object`.unsafe { bindings::dma_resv_lock(obj.raw_dma_resv(), ptr::null_mut()) };Self(obj)- }
+}
+impl<'a, T: DriverObject, C: DeviceContext> Drop for DmaResvGuard<'a, T, C> {
- #[inline(always)]
- fn drop(&mut self) {
// SAFETY: We are releasing the lock grabbed during the creation of this object.unsafe { bindings::dma_resv_unlock(self.0.raw_dma_resv()) };- }
+}