[PATCH v3 12/13] rust: drm: Pass registration data to ioctl handlers

[Danilo Krummrich <dakr@kernel.org>]

Pass registration data to ioctl handlers via
drm::Device<Registered>::registration_data_with(). The closure's HRTB
ties the lifetime to the closure scope, and the pointer cast shortens it
from 'static internally. The reference is valid for the duration of the
drm_dev_enter/exit critical section held by RegistrationGuard.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 drivers/gpu/drm/nova/file.rs |  3 +++
 drivers/gpu/drm/tyr/file.rs  |  1 +
 rust/kernel/drm/ioctl.rs     | 16 +++++++++++++---
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index a3b7bd36792c..4c9fa409a8be 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -24,6 +24,7 @@ impl File {
     /// IOCTL: get_param: Query GPU / driver metadata.
     pub(crate) fn get_param(
         dev: &NovaDevice,
+        _reg_data: &(),
         getparam: &mut uapi::drm_nova_getparam,
         _file: &drm::File<File>,
     ) -> Result<u32> {
@@ -44,6 +45,7 @@ pub(crate) fn get_param(
     /// IOCTL: gem_create: Create a new DRM GEM object.
     pub(crate) fn gem_create(
         dev: &NovaDevice,
+        _reg_data: &(),
         req: &mut uapi::drm_nova_gem_create,
         file: &drm::File<File>,
     ) -> Result<u32> {
@@ -57,6 +59,7 @@ pub(crate) fn gem_create(
     /// IOCTL: gem_info: Query GEM metadata.
     pub(crate) fn gem_info(
         _dev: &NovaDevice,
+        _reg_data: &(),
         req: &mut uapi::drm_nova_gem_info,
         file: &drm::File<File>,
     ) -> Result<u32> {
diff --git a/drivers/gpu/drm/tyr/file.rs b/drivers/gpu/drm/tyr/file.rs
index 31411da203c5..6262114c6a8d 100644
--- a/drivers/gpu/drm/tyr/file.rs
+++ b/drivers/gpu/drm/tyr/file.rs
@@ -29,6 +29,7 @@ fn open(_dev: &drm::Device<Self::Driver>) -> Result<Pin<KBox<Self>>> {
 impl TyrDrmFileData {
     pub(crate) fn dev_query(
         ddev: &TyrDrmDevice,
+        _reg_data: &(),
         devquery: &mut uapi::drm_panthor_dev_query,
         _file: &TyrDrmFile,
     ) -> Result<u32> {
diff --git a/rust/kernel/drm/ioctl.rs b/rust/kernel/drm/ioctl.rs
index c6a03be018e6..ecc1a0383635 100644
--- a/rust/kernel/drm/ioctl.rs
+++ b/rust/kernel/drm/ioctl.rs
@@ -83,6 +83,7 @@ pub mod internal {
 ///
 /// ```ignore
 /// fn foo(device: &kernel::drm::Device<Self>,
+///        reg_data: &<Self::RegistrationData as kernel::types::ForLt>::Of<'_>,
 ///        data: &mut uapi::argument_type,
 ///        file: &kernel::drm::File<Self::File>,
 /// ) -> Result<u32>
@@ -143,9 +144,16 @@ macro_rules! declare_drm_ioctls {
                             // type to `$func`'s first parameter, which the compiler cannot infer
                             // through method resolution and associated-type projections alone.
                             #[allow(unreachable_code)]
-                            let _ = || $func(dev, unreachable!(), unreachable!());
+                            let _ = || {
+                                $func(
+                                    dev,
+                                    unreachable!(),
+                                    unreachable!(),
+                                    unreachable!(),
+                                )
+                            };
 
-                            let Some(_guard) = dev.registration_guard() else {
+                            let Some(guard) = dev.registration_guard() else {
                                 return $crate::error::code::ENODEV.to_errno();
                             };
                             // SAFETY: The ioctl argument has size `_IOC_SIZE(cmd)`, which we
@@ -160,7 +168,9 @@ macro_rules! declare_drm_ioctls {
                             // SAFETY: This is just the DRM file structure
                             let file = unsafe { $crate::drm::File::from_raw(raw_file) };
 
-                            match $func(dev, data, file) {
+                            match guard.registration_data_with(|reg_data| {
+                                $func(&*guard, reg_data, data, file)
+                            }) {
                                 Err(e) => e.to_errno(),
                                 Ok(i) => i.try_into()
                                             .unwrap_or($crate::error::code::ERANGE.to_errno()),
-- 
2.54.0