From: Asahi Lina <l...@asahilina.net>
Implement the DRM driver `Registration`.
The `Registration` structure is responsible to register and unregister a
DRM driver. It makes use of the `Devres` container in order to allow the
`Registration` to be owned by devres, such that it is automatically
dropped (and the DRM driver unregistered) once the parent device is
unbound.
Signed-off-by: Asahi Lina <l...@asahilina.net>
[ Rework of drm::Registration
* move VTABLE to drm::Device to prevent use-after-free bugs; VTABLE
needs to be bound to the lifetime of drm::Device, not the
drm::Registration
* combine new() and register() to get rid of the registered boolean
* remove file_operations
* move struct drm_device creation to drm::Device
* introduce Devres
* original source archive: https://archive.is/Pl9ys
- Danilo ]
Signed-off-by: Danilo Krummrich <d...@kernel.org>
---
rust/kernel/drm/driver.rs | 60 ++++++++++++++++++++++++++++++++++++++-
rust/kernel/drm/mod.rs | 1 +
2 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs
index 6d09d1933d3e..96bb287eada2 100644
--- a/rust/kernel/drm/driver.rs
+++ b/rust/kernel/drm/driver.rs
@@ -4,7 +4,15 @@
//!
//! C header:
[`include/linux/drm/drm_drv.h`](srctree/include/linux/drm/drm_drv.h)
-use crate::{bindings, drm, str::CStr};
+use crate::{
+ bindings, device,
+ devres::Devres,
+ drm,
+ error::{Error, Result},
+ prelude::*,
+ str::CStr,
+ types::ARef,
+};
use macros::vtable;
/// Driver use the GEM memory manager. This should be set for all modern
drivers.
@@ -107,3 +115,53 @@ pub trait Driver {
/// IOCTL list. See `kernel::drm::ioctl::declare_drm_ioctls!{}`.
const IOCTLS: &'static [drm::ioctl::DrmIoctlDescriptor];
}
+
+/// The registration type of a `drm::Device`.
+///
+/// Once the `Registration` structure is dropped, the device is unregistered.
+pub struct Registration<T: Driver>(ARef<drm::Device<T>>);
+
+impl<T: Driver> Registration<T> {
+ /// Creates a new [`Registration`] and registers it.
+ pub fn new(drm: &drm::Device<T>, flags: usize) -> Result<Self> {
+ // SAFETY: Safe by the invariants of `drm::Device`.
+ let ret = unsafe { bindings::drm_dev_register(drm.as_raw(), flags) };
+ if ret < 0 {
+ return Err(Error::from_errno(ret));
+ }
+
+ Ok(Self(drm.into()))
+ }
+
+ /// Same as [`Registration::new`}, but transfers ownership of the
[`Registration`] to
+ /// [`Devres`].
+ pub fn new_foreign_owned(drm: &drm::Device<T>, dev: &device::Device,
flags: usize) -> Result {
+ if drm.as_ref().as_raw() != dev.as_raw() {
+ return Err(EINVAL);
+ }
+
+ let reg = Registration::<T>::new(drm, flags)?;
+ Devres::new_foreign_owned(dev, reg, GFP_KERNEL)
+ }
+
+ /// Returns a reference to the `Device` instance for this registration.
+ pub fn device(&self) -> &drm::Device<T> {
+ &self.0
+ }
+}
+
+// SAFETY: `Registration` doesn't offer any methods or access to fields when
shared between
+// threads, hence it's safe to share it.
+unsafe impl<T: Driver> Sync for Registration<T> {}
+
+// SAFETY: Registration with and unregistration from the DRM subsystem can
happen from any thread.
+unsafe impl<T: Driver> Send for Registration<T> {}
+
+impl<T: Driver> Drop for Registration<T> {
+ /// Removes the registration from the kernel if it has completed
successfully before.
+ fn drop(&mut self) {
+ // SAFETY: Safe by the invariant of `ARef<drm::Device<T>>`. The
existence of this
+ // `Registration` also guarantees the this `drm::Device` is actually
registered.
+ unsafe { bindings::drm_dev_unregister(self.0.as_raw()) };
+ }
+}
diff --git a/rust/kernel/drm/mod.rs b/rust/kernel/drm/mod.rs
index 967854a2083e..2d88e70ba607 100644
--- a/rust/kernel/drm/mod.rs
+++ b/rust/kernel/drm/mod.rs
@@ -9,6 +9,7 @@
pub use self::device::Device;
pub use self::driver::Driver;
pub use self::driver::DriverInfo;
+pub use self::driver::Registration;
pub(crate) mod private {
pub trait Sealed {}
--
2.49.0
