[PATCH v3 10/27] rust: pci: make Driver trait lifetime-parameterized

[Danilo Krummrich <dakr@kernel.org>]

Add a 'bound lifetime to the associated Data, changing type Data to type
Data<'bound>.

This allows the driver's bus device private data to capture the device /
driver bound lifetime; device resources can be stored directly by
reference rather than requiring Devres.

The probe() and unbind() callbacks thus gain a 'bound lifetime parameter
on the methods themselves; avoiding a global lifetime on the trait impl.

Existing drivers set type Data<'bound> = Self, preserving the current
behavior.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 drivers/gpu/nova-core/driver.rs       |  9 ++++++---
 rust/kernel/pci.rs                    | 24 +++++++++++++-----------
 samples/rust/rust_dma.rs              |  7 +++++--
 samples/rust/rust_driver_auxiliary.rs |  7 +++++--
 samples/rust/rust_driver_pci.rs       |  7 +++++--
 5 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index 699e27046c93..fe4eafe1ebf0 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -74,10 +74,13 @@ pub(crate) struct NovaCore {
 
 impl pci::Driver for NovaCore {
     type IdInfo = ();
-    type Data = Self;
+    type Data<'bound> = Self;
     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
 
-    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
+    fn probe<'bound>(
+        pdev: &'bound pci::Device<Core>,
+        _info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self, Error> + 'bound {
         pin_init::pin_init_scope(move || {
             dev_dbg!(pdev, "Probe Nova Core GPU driver.\n");
 
@@ -109,7 +112,7 @@ fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, E
         })
     }
 
-    fn unbind(pdev: &pci::Device<Core>, this: Pin<&Self>) {
+    fn unbind<'bound>(pdev: &'bound pci::Device<Core>, this: Pin<&'bound Self>) {
         this.gpu.unbind(pdev.as_ref());
     }
 }
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index c06ac3fb2a64..8060861199d4 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -64,7 +64,7 @@
 // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`.
 unsafe impl<T: Driver> driver::DriverLayout for Adapter<T> {
     type DriverType = bindings::pci_driver;
-    type DriverData<'bound> = T::Data;
+    type DriverData<'bound> = T::Data<'bound>;
     const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);
 }
 
@@ -130,7 +130,7 @@ extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) {
         // 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::Data>>`.
-        let data = unsafe { pdev.as_ref().drvdata_borrow::<T::Data>() };
+        let data = unsafe { pdev.as_ref().drvdata_borrow::<T::Data<'_>>() };
 
         T::unbind(pdev, data);
     }
@@ -279,13 +279,13 @@ macro_rules! pci_device_table {
 ///
 /// impl pci::Driver for MyDriver {
 ///     type IdInfo = ();
-///     type Data = Self;
+///     type Data<'bound> = Self;
 ///     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
 ///
-///     fn probe(
-///         _pdev: &pci::Device<Core>,
-///         _id_info: &Self::IdInfo,
-///     ) -> impl PinInit<Self, Error> {
+///     fn probe<'bound>(
+///         _pdev: &'bound pci::Device<Core>,
+///         _id_info: &'bound Self::IdInfo,
+///     ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
 ///         Err(ENODEV)
 ///     }
 /// }
@@ -302,7 +302,7 @@ pub trait Driver: Send {
     type IdInfo: 'static;
 
     /// The type of the driver's bus device private data.
-    type Data;
+    type Data<'bound>: 'bound;
 
     /// The table of device ids supported by the driver.
     const ID_TABLE: IdTable<Self::IdInfo>;
@@ -311,8 +311,10 @@ pub trait Driver: Send {
     ///
     /// Called when a new pci device is added or discovered. Implementers should
     /// attempt to initialize the device here.
-    fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo)
-        -> impl PinInit<Self::Data, Error>;
+    fn probe<'bound>(
+        dev: &'bound Device<device::Core>,
+        id_info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound;
 
     /// PCI driver unbind.
     ///
@@ -324,7 +326,7 @@ fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo)
     /// operations to gracefully tear down the device.
     ///
     /// Otherwise, release operations for driver resources should be performed in `Drop`.
-    fn unbind(dev: &Device<device::Core>, this: Pin<&Self::Data>) {
+    fn unbind<'bound>(dev: &'bound Device<device::Core>, this: Pin<&'bound Self::Data<'bound>>) {
         let _ = (dev, this);
     }
 }
diff --git a/samples/rust/rust_dma.rs b/samples/rust/rust_dma.rs
index e583c6b8390a..943655a85ec6 100644
--- a/samples/rust/rust_dma.rs
+++ b/samples/rust/rust_dma.rs
@@ -58,10 +58,13 @@ unsafe impl kernel::transmute::FromBytes for MyStruct {}
 
 impl pci::Driver for DmaSampleDriver {
     type IdInfo = ();
-    type Data = Self;
+    type Data<'bound> = Self;
     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
 
-    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
+    fn probe<'bound>(
+        pdev: &'bound pci::Device<Core>,
+        _info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self, Error> + 'bound {
         pin_init::pin_init_scope(move || {
             dev_info!(pdev, "Probe DMA test driver.\n");
 
diff --git a/samples/rust/rust_driver_auxiliary.rs b/samples/rust/rust_driver_auxiliary.rs
index 61d5bf2e8c0d..2f57912fe87f 100644
--- a/samples/rust/rust_driver_auxiliary.rs
+++ b/samples/rust/rust_driver_auxiliary.rs
@@ -66,11 +66,14 @@ struct ParentDriver {
 
 impl pci::Driver for ParentDriver {
     type IdInfo = ();
-    type Data = Self;
+    type Data<'bound> = Self;
 
     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
 
-    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
+    fn probe<'bound>(
+        pdev: &'bound pci::Device<Core>,
+        _info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self, Error> + 'bound {
         Ok(Self {
             _reg0: auxiliary::Registration::new(
                 pdev.as_ref(),
diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs
index f43c6a660b39..30b9311812f3 100644
--- a/samples/rust/rust_driver_pci.rs
+++ b/samples/rust/rust_driver_pci.rs
@@ -140,11 +140,14 @@ fn config_space(pdev: &pci::Device<Bound>) {
 
 impl pci::Driver for SampleDriver {
     type IdInfo = TestIndex;
-    type Data = Self;
+    type Data<'bound> = Self;
 
     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
 
-    fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> impl PinInit<Self, Error> {
+    fn probe<'bound>(
+        pdev: &'bound pci::Device<Core>,
+        info: &'bound Self::IdInfo,
+    ) -> impl PinInit<Self, Error> + 'bound {
         pin_init::pin_init_scope(move || {
             let vendor = pdev.vendor_id();
             dev_dbg!(
-- 
2.54.0