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rust: usb: make Driver trait lifetime-parameterized

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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 disconnect() 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.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://patch.msgid.link/20260525202921.124698-16-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich 2026-05-25 22:21:02 +02:00
parent 46f651d886
commit a3f09f8e47
2 changed files with 28 additions and 21 deletions
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37
rust/kernel/usb.rs
View File

@ -41,7 +41,7 @@
// - `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::usb_driver;
type DriverData<'bound> = T::Data;
type DriverData<'bound> = T::Data<'bound>;
const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);
}
@ -109,8 +109,8 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) {
// 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::Data>>`.
let data = unsafe { dev.drvdata_borrow::<T::Data>() };
// and stored a `Pin<KBox<T::Data<'_>>>`.
let data = unsafe { dev.drvdata_borrow::<T::Data<'_>>() };
T::disconnect(intf, data);
}
@ -287,18 +287,22 @@ macro_rules! usb_device_table {
///
/// impl usb::Driver for MyDriver {
/// type IdInfo = ();
/// type Data = Self;
/// type Data<'bound> = Self;
/// const ID_TABLE: usb::IdTable<Self::IdInfo> = &USB_TABLE;
///
/// fn probe(
/// _interface: &usb::Interface<Core<'_>>,
/// fn probe<'bound>(
/// _interface: &'bound usb::Interface<Core<'_>>,
/// _id: &usb::DeviceId,
/// _info: &Self::IdInfo,
/// ) -> impl PinInit<Self::Data, Error> {
/// _info: &'bound Self::IdInfo,
/// ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
/// Err(ENODEV)
/// }
///
/// fn disconnect(_interface: &usb::Interface<Core<'_>>, _data: Pin<&Self::Data>) {}
/// fn disconnect<'bound>(
/// _interface: &'bound usb::Interface<Core<'_>>,
/// _data: Pin<&Self::Data<'bound>>,
/// ) {
/// }
/// }
///```
pub trait Driver {
@ -306,7 +310,7 @@ pub trait Driver {
type IdInfo: 'static;
/// The type of the driver's bus device private data.
type Data: Send;
type Data<'bound>: Send + 'bound;
/// The table of device ids supported by the driver.
const ID_TABLE: IdTable<Self::IdInfo>;
@ -315,16 +319,19 @@ pub trait Driver {
///
/// Called when a new USB interface is bound to this driver.
/// Implementers should attempt to initialize the interface here.
fn probe(
interface: &Interface<device::Core<'_>>,
fn probe<'bound>(
interface: &'bound Interface<device::Core<'_>>,
id: &DeviceId,
id_info: &Self::IdInfo,
) -> impl PinInit<Self::Data, Error>;
id_info: &'bound Self::IdInfo,
) -> impl PinInit<Self::Data<'bound>, Error> + 'bound;
/// USB driver disconnect.
///
/// Called when the USB interface is about to be unbound from this driver.
fn disconnect(interface: &Interface<device::Core<'_>>, data: Pin<&Self::Data>);
fn disconnect<'bound>(
interface: &'bound Interface<device::Core<'_>>,
data: Pin<&Self::Data<'bound>>,
);
}
/// A USB interface.

12
samples/rust/rust_driver_usb.rs
View File

@ -26,21 +26,21 @@ struct SampleDriver {
impl usb::Driver for SampleDriver {
type IdInfo = ();
type Data = Self;
type Data<'bound> = Self;
const ID_TABLE: usb::IdTable<Self::IdInfo> = &USB_TABLE;
fn probe(
intf: &usb::Interface<Core<'_>>,
fn probe<'bound>(
intf: &'bound usb::Interface<Core<'_>>,
_id: &usb::DeviceId,
_info: &Self::IdInfo,
) -> impl PinInit<Self, Error> {
_info: &'bound Self::IdInfo,
) -> impl PinInit<Self, Error> + 'bound {
let dev: &device::Device<Core<'_>> = intf.as_ref();
dev_info!(dev, "Rust USB driver sample probed\n");
Ok(Self { _intf: intf.into() })
}
fn disconnect(intf: &usb::Interface<Core<'_>>, _data: Pin<&Self>) {
fn disconnect<'bound>(intf: &'bound usb::Interface<Core<'_>>, _data: Pin<&Self>) {
let dev: &device::Device<Core<'_>> = intf.as_ref();
dev_info!(dev, "Rust USB driver sample disconnected\n");
}