[WIP RFC v2 31/35] rust: drm: Add Device::event_lock()

[Daniel Almeida]

Hi Lyude,

> On 30 Sep 2024, at 20:10, Lyude Paul <lyude at redhat.com> wrote:
> 
> This is just a crate-private helper to use Lock::from_raw() to provide an
> immutable reference to the DRM event_lock, so that it can be used like a
> normal rust spinlock. We'll need this for adding vblank related bindings.
> 
> Signed-off-by: Lyude Paul <lyude at redhat.com>
> ---
> rust/kernel/drm/device.rs | 7 +++++++
> 1 file changed, 7 insertions(+)
> 
> diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs
> index d4d6b1185f6a6..207e7ea87cf8f 100644
> --- a/rust/kernel/drm/device.rs
> +++ b/rust/kernel/drm/device.rs
> @@ -15,6 +15,7 @@
>     error::from_err_ptr,
>     error::Result,
>     types::{ARef, AlwaysRefCounted, ForeignOwnable, Opaque},
> +    sync::*,
> };
> use core::{
>     ffi::c_void,
> @@ -159,6 +160,12 @@ pub fn data(&self) -> <T::Data as ForeignOwnable>::Borrowed<'_> {
>         unsafe { <T::Data as ForeignOwnable>::from_foreign(drm.raw_data()) };
>     }
> 
> +    /// Returns a reference to the `event` spinlock
> +    pub(crate) fn event_lock(&self) -> &SpinLockIrq<()> {
> +        // SAFETY: `event_lock` is initialized for as long as `self` is exposed to users
> +        unsafe { SpinLockIrq::from_raw(&mut (*self.as_raw()).event_lock) }
> +    }
> +

I see this depends on your SpinLockIrq series, which I will get to later. I will defer any comments
until then.

>     pub(crate) const fn has_kms() -> bool {
>         <T::Kms as KmsImplPrivate>::MODE_CONFIG_OPS.is_some()
>     }
> -- 
> 2.46.1
> 
> 

— Daniel