[PATCH v2 6/7] rust: drm: return impl PinInit from DriverFile::open()

[Danilo Krummrich <dakr@kernel.org>]

Change DriverFile::open() to return impl PinInit<Self, Error> instead of
Result<Pin<KBox<Self>>>, consistent with how bus device private data
works.

Drivers no longer need to allocate a Pin<KBox<_>> themselves; they just
return an initializer and the subsystem takes care of the allocation.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 drivers/gpu/drm/nova/file.rs | 5 ++---
 drivers/gpu/drm/tyr/file.rs  | 4 ++--
 rust/kernel/drm/file.rs      | 5 +++--
 rust/kernel/drm/gem/shmem.rs | 4 ++--
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index a05264917a0b..13642f83289d 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -7,7 +7,6 @@
 };
 use crate::gem::NovaObject;
 use kernel::{
-    alloc::flags::*,
     drm::{
         self,
         gem::BaseObject,
@@ -103,8 +102,8 @@ fn write_info<T: AsBytes>(info: &mut uapi::drm_nova_info, value: T) -> Result {
 impl drm::file::DriverFile for File {
     type Driver = NovaDriver;
 
-    fn open(_dev: &NovaDevice) -> Result<Pin<KBox<Self>>> {
-        Ok(KBox::new(Self, GFP_KERNEL)?.into())
+    fn open(_dev: &NovaDevice) -> impl PinInit<Self, Error> {
+        Ok(Self)
     }
 }
 
diff --git a/drivers/gpu/drm/tyr/file.rs b/drivers/gpu/drm/tyr/file.rs
index 9f60a90d4948..6850708cfcdd 100644
--- a/drivers/gpu/drm/tyr/file.rs
+++ b/drivers/gpu/drm/tyr/file.rs
@@ -25,8 +25,8 @@ pub(crate) struct TyrDrmFileData {}
 impl drm::file::DriverFile for TyrDrmFileData {
     type Driver = TyrDrmDriver;
 
-    fn open(_dev: &drm::Device<Self::Driver>) -> Result<Pin<KBox<Self>>> {
-        KBox::try_pin_init(try_pin_init!(Self {}), GFP_KERNEL)
+    fn open(_dev: &drm::Device<Self::Driver>) -> impl PinInit<Self, Error> {
+        Ok(Self {})
     }
 }
 
diff --git a/rust/kernel/drm/file.rs b/rust/kernel/drm/file.rs
index 10160601ce5a..bd5e4ca2977f 100644
--- a/rust/kernel/drm/file.rs
+++ b/rust/kernel/drm/file.rs
@@ -18,7 +18,7 @@ pub trait DriverFile {
     type Driver: drm::Driver;
 
     /// Open a new file (called when a client opens the DRM device).
-    fn open(device: &drm::Device<Self::Driver>) -> Result<Pin<KBox<Self>>>;
+    fn open(device: &drm::Device<Self::Driver>) -> impl PinInit<Self, Error>;
 }
 
 /// An open DRM File.
@@ -70,7 +70,8 @@ pub(crate) extern "C" fn open_callback(
         // SAFETY: `raw_file` is a valid pointer to a `struct drm_file`.
         let file = unsafe { File::<T>::from_raw(raw_file) };
 
-        let inner = match T::open(drm) {
+        let init = T::open(drm);
+        let inner = match KBox::try_pin_init(init, GFP_KERNEL) {
             Err(e) => {
                 return e.to_errno();
             }
diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs
index 24cb5343e0db..1a4f81e3b5b5 100644
--- a/rust/kernel/drm/gem/shmem.rs
+++ b/rust/kernel/drm/gem/shmem.rs
@@ -604,8 +604,8 @@ struct KunitObject {}
     impl drm::file::DriverFile for KunitFile {
         type Driver = KunitDriver;
 
-        fn open(_dev: &drm::Device<KunitDriver>) -> Result<Pin<KBox<Self>>> {
-            Ok(KBox::new(Self, GFP_KERNEL)?.into())
+        fn open(_dev: &drm::Device<KunitDriver>) -> impl PinInit<Self, Error> {
+            Ok(Self)
         }
     }
 
-- 
2.56.0