From 6bbaa93912bfdfd5ffdc804275cc6a444c9400af Mon Sep 17 00:00:00 2001
From: Danilo Krummrich <dakr@kernel.org>
Date: Tue, 21 Oct 2025 00:34:23 +0200
Subject: [PATCH] rust: device: narrow the generic of drvdata_obtain()

Let T be the actual private driver data type without the surrounding
box, as it leaves less room for potential bugs.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/auxiliary.rs | 2 +-
 rust/kernel/device.rs    | 4 ++--
 rust/kernel/pci.rs       | 2 +-
 rust/kernel/platform.rs  | 2 +-
 rust/kernel/usb.rs       | 4 ++--
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index e12f78734606..a6a2b23befce 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -85,7 +85,7 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `remove_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        drop(unsafe { adev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() });
+        drop(unsafe { adev.as_ref().drvdata_obtain::<T>() });
     }
 }
 
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 343996027c89..106aa57a6385 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -215,7 +215,7 @@ impl Device<CoreInternal> {
     /// - Must only be called once after a preceding call to [`Device::set_drvdata`].
     /// - The type `T` must match the type of the `ForeignOwnable` previously stored by
     ///   [`Device::set_drvdata`].
-    pub unsafe fn drvdata_obtain<T: ForeignOwnable>(&self) -> T {
+    pub unsafe fn drvdata_obtain<T: 'static>(&self) -> Pin<KBox<T>> {
         // SAFETY: By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`.
         let ptr = unsafe { bindings::dev_get_drvdata(self.as_raw()) };
 
@@ -224,7 +224,7 @@ impl Device<CoreInternal> {
         //   `into_foreign()`.
         // - `dev_get_drvdata()` guarantees to return the same pointer given to `dev_set_drvdata()`
         //   in `into_foreign()`.
-        unsafe { T::from_foreign(ptr.cast()) }
+        unsafe { Pin::<KBox<T>>::from_foreign(ptr.cast()) }
     }
 
     /// Borrow the driver's private data bound to this [`Device`].
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 039a0d81d363..b68ef4e575fc 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -94,7 +94,7 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `remove_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        let data = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+        let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
 
         T::unbind(pdev, data.as_ref());
     }
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 043721fdb6d8..8f7522c4cf89 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -91,7 +91,7 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `remove_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        let data = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+        let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
 
         T::unbind(pdev, data.as_ref());
     }
diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index fa8367c0dbaa..92215fdc3c6a 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -87,9 +87,9 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `disconnect_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        let data = unsafe { dev.drvdata_obtain::<Pin<KBox<T>>>() };
+        let data = unsafe { dev.drvdata_obtain::<T>() };
 
-        T::disconnect(intf, data.as_ref());
+        T::disconnect(intf, data.data());
     }
 }