linux-kernel - [PATCH 4/8] rust: pci: use generic device drvdata accessors

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Message-ID: <20250621195118.124245-5-dakr@kernel.org>
Date: Sat, 21 Jun 2025 21:43:30 +0200
From: Danilo Krummrich <dakr@...nel.org>
To: gregkh@...uxfoundation.org,
	rafael@...nel.org,
	ojeda@...nel.org,
	alex.gaynor@...il.com,
	boqun.feng@...il.com,
	gary@...yguo.net,
	bjorn3_gh@...tonmail.com,
	benno.lossin@...ton.me,
	a.hindborg@...nel.org,
	aliceryhl@...gle.com,
	tmgross@...ch.edu,
	david.m.ertman@...el.com,
	ira.weiny@...el.com,
	leon@...nel.org,
	kwilczynski@...nel.org,
	bhelgaas@...gle.com
Cc: rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org,
	Danilo Krummrich <dakr@...nel.org>
Subject: [PATCH 4/8] rust: pci: use generic device drvdata accessors

Take advantage of the generic drvdata accessors of the generic Device
type.

While at it, use from_result() instead of match.

Signed-off-by: Danilo Krummrich <dakr@...nel.org>
---
 rust/helpers/pci.c | 10 ----------
 rust/kernel/pci.rs | 31 ++++++++++++++-----------------
 2 files changed, 14 insertions(+), 27 deletions(-)

diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c
index cd0e6bf2cc4d..ef9cb38c81a6 100644
--- a/rust/helpers/pci.c
+++ b/rust/helpers/pci.c
@@ -2,16 +2,6 @@
 
 #include <linux/pci.h>
 
-void rust_helper_pci_set_drvdata(struct pci_dev *pdev, void *data)
-{
-	pci_set_drvdata(pdev, data);
-}
-
-void *rust_helper_pci_get_drvdata(struct pci_dev *pdev)
-{
-	return pci_get_drvdata(pdev);
-}
-
 resource_size_t rust_helper_pci_resource_len(struct pci_dev *pdev, int bar)
 {
 	return pci_resource_len(pdev, bar);
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 8435f8132e38..064e74a90904 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -10,11 +10,11 @@
     device_id::RawDeviceId,
     devres::Devres,
     driver,
-    error::{to_result, Result},
+    error::{from_result, to_result, Result},
     io::Io,
     io::IoRaw,
     str::CStr,
-    types::{ARef, ForeignOwnable, Opaque},
+    types::{ARef, Opaque},
     ThisModule,
 };
 use core::{
@@ -66,35 +66,32 @@ extern "C" fn probe_callback(
         // `struct pci_dev`.
         //
         // INVARIANT: `pdev` is valid for the duration of `probe_callback()`.
-        let pdev = unsafe { &*pdev.cast::<Device<device::Core>>() };
+        let pdev = unsafe { &*pdev.cast::<Device<device::Internal>>() };
 
         // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct pci_device_id` and
         // does not add additional invariants, so it's safe to transmute.
         let id = unsafe { &*id.cast::<DeviceId>() };
         let info = T::ID_TABLE.info(id.index());
 
-        match T::probe(pdev, info) {
-            Ok(data) => {
-                // Let the `struct pci_dev` own a reference of the driver's private data.
-                // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
-                // `struct pci_dev`.
-                unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign() as _) };
-            }
-            Err(err) => return Error::to_errno(err),
-        }
+        from_result(|| {
+            let data = T::probe(pdev, info)?;
 
-        0
+            pdev.as_ref().set_drvdata(data);
+            Ok(0)
+        })
     }
 
     extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) {
         // SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a
         // `struct pci_dev`.
-        let ptr = unsafe { bindings::pci_get_drvdata(pdev) }.cast();
+        //
+        // INVARIANT: `pdev` is valid for the duration of `remove_callback()`.
+        let pdev = unsafe { &*pdev.cast::<Device<device::Internal>>() };
 
         // SAFETY: `remove_callback` is only ever called after a successful call to
-        // `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized
-        // `KBox<T>` pointer created through `KBox::into_foreign`.
-        let _ = unsafe { KBox::<T>::from_foreign(ptr) };
+        // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
+        // and stored a `Pin<KBox<T>>`.
+        let _ = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
     }
 }
 
-- 
2.49.0