[PATCH v2 7/7] drm: nova: convert to use DRM registration data

[Danilo Krummrich]

Move the auxiliary device reference from drm::Device data into
RegistrationData, replacing the ARef<auxiliary::Device> with a borrowed
&'bound auxiliary::Device<Bound>. This makes the data lifetime-aware and
exercises the registration data path through the ioctl handlers.

Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
 drivers/gpu/drm/nova/driver.rs | 20 ++++++++++----------
 drivers/gpu/drm/nova/file.rs   | 19 +++++++++++--------
 2 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs
index 4267e6e6dbb4..f46d7ff6fee3 100644
--- a/drivers/gpu/drm/nova/driver.rs
+++ b/drivers/gpu/drm/nova/driver.rs
@@ -3,6 +3,7 @@
 use kernel::{
     auxiliary,
     device::{
+        Bound,
         Core,
         DeviceContext, //
     },
@@ -13,7 +14,7 @@
     },
     prelude::*,
     sync::aref::ARef,
-    types::ForLt, //
+    types::CovariantForLt, //
 };
 
 use crate::file::File;
@@ -30,9 +31,8 @@ pub(crate) struct Nova<'bound> {
 /// Convienence type alias for the DRM device type for this driver
 pub(crate) type NovaDevice<Ctx = drm::Registered> = drm::Device<NovaDriver, Ctx>;
 
-#[pin_data]
-pub(crate) struct NovaData {
-    pub(crate) adev: ARef<auxiliary::Device>,
+pub(crate) struct NovaData<'bound> {
+    pub(crate) adev: &'bound auxiliary::Device<Bound>,
 }
 
 const INFO: drm::DriverInfo = drm::DriverInfo {
@@ -65,10 +65,10 @@ fn probe<'bound>(
         adev: &'bound auxiliary::Device<Core<'_>>,
         _info: &'bound Self::IdInfo,
     ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
-        let data = try_pin_init!(NovaData { adev: adev.into() });
-
-        let drm = drm::UnregisteredDevice::<Self>::new(adev, data)?;
-        let reg = drm::Registration::new(adev.as_ref(), drm, (), 0)?;
+        let drm = drm::UnregisteredDevice::<Self>::new(adev, Ok(()))?;
+        let reg_data = NovaData { adev };
+        // SAFETY: We never bypass the destructor of `reg`.
+        let reg = unsafe { drm::Registration::new_with_lt(adev.as_ref(), drm, reg_data, 0)? };
 
         Ok(Nova {
             drm: reg.device().into(),
@@ -79,8 +79,8 @@ fn probe<'bound>(
 
 #[vtable]
 impl drm::Driver for NovaDriver {
-    type Data = NovaData;
-    type RegistrationData = ForLt!(());
+    type Data = ();
+    type RegistrationData = CovariantForLt!(NovaData<'_>);
     type File = File;
     type Object<Ctx: drm::DeviceContext> = gem::Object<NovaObject, Ctx>;
     type ParentDevice<Ctx: DeviceContext> = auxiliary::Device<Ctx>;
diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index df9760947d58..cd6c37b01e22 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -1,6 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use crate::driver::{NovaDevice, NovaDriver};
+use crate::driver::{
+    NovaData,
+    NovaDevice,
+    NovaDriver, //
+};
 use crate::gem::NovaObject;
 use kernel::{
     alloc::flags::*,
@@ -25,15 +29,14 @@ fn open(_dev: &NovaDevice) -> Result<Pin<KBox<Self>>> {
 impl File {
     /// IOCTL: get_param: Query GPU / driver metadata.
     pub(crate) fn get_param(
-        dev: &NovaDevice,
+        _dev: &NovaDevice,
         _adev: &auxiliary::Device<Bound>,
-        _reg_data: &(),
+        reg_data: &NovaData<'_>,
         getparam: &mut uapi::drm_nova_getparam,
         _file: &drm::File<File>,
     ) -> Result<u32> {
-        let adev = &dev.adev;
-        let parent = adev.parent();
-        let pdev: &pci::Device = parent.try_into()?;
+        let parent = reg_data.adev.parent();
+        let pdev: &pci::Device<Bound> = parent.try_into()?;
 
         let value = match getparam.param as u32 {
             uapi::NOVA_GETPARAM_VRAM_BAR_SIZE => pdev.resource_len(1)?,
@@ -49,7 +52,7 @@ pub(crate) fn get_param(
     pub(crate) fn gem_create(
         dev: &NovaDevice,
         _adev: &auxiliary::Device<Bound>,
-        _reg_data: &(),
+        _reg_data: &NovaData<'_>,
         req: &mut uapi::drm_nova_gem_create,
         file: &drm::File<File>,
     ) -> Result<u32> {
@@ -64,7 +67,7 @@ pub(crate) fn gem_create(
     pub(crate) fn gem_info(
         _dev: &NovaDevice,
         _adev: &auxiliary::Device<Bound>,
-        _reg_data: &(),
+        _reg_data: &NovaData<'_>,
         req: &mut uapi::drm_nova_gem_info,
         file: &drm::File<File>,
     ) -> Result<u32> {
-- 
2.54.0