Make usb::Driver take a lifetime parameter 'bound that ties device resources to the binding scope.
Internally, Adapter<T: Driver> becomes Adapter<F: ForLt> with a bound for<'bound> F::Of<'bound>: Driver<'bound>; module_usb_driver! wraps the driver type in ForLt!() so drivers don't have to. Signed-off-by: Danilo Krummrich <[email protected]> --- rust/kernel/usb.rs | 85 ++++++++++++++++++++------------- samples/rust/rust_driver_usb.rs | 14 +++--- 2 files changed, 59 insertions(+), 40 deletions(-) diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs index 442e456fd2d3..450be2b7c542 100644 --- a/rust/kernel/usb.rs +++ b/rust/kernel/usb.rs @@ -35,22 +35,35 @@ }; /// An adapter for the registration of USB drivers. -pub struct Adapter<T: Driver>(T); +/// +/// `F` is a [`ForLt`](trait@ForLt) type that maps lifetimes to the driver's device +/// private data type, i.e. `F::Of<'bound>` is the driver struct +/// parameterized by `'bound`. The macro `module_usb_driver!` generates +/// this automatically via `ForLt!()`. +pub struct Adapter<F>(PhantomData<F>); // SAFETY: // - `bindings::usb_driver` is a C type declared as `repr(C)`. -// - `T` is the type of the driver's device private data. +// - `F::Of<'static>` is the stored type of the driver's device private data. // - `struct usb_driver` embeds a `struct device_driver`. // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`. -unsafe impl<T: Driver + 'static> driver::DriverLayout for Adapter<T> { +unsafe impl<F> driver::DriverLayout for Adapter<F> +where + F: ForLt + 'static, + for<'bound> F::Of<'bound>: Driver<'bound>, +{ type DriverType = bindings::usb_driver; - type DriverData = ForLt!(T); + type DriverData = F; const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver); } // SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if // a preceding call to `register` has been successful. -unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> { +unsafe impl<F> driver::RegistrationOps for Adapter<F> +where + F: ForLt + 'static, + for<'bound> F::Of<'bound>: Driver<'bound>, +{ unsafe fn register( udrv: &Opaque<Self::DriverType>, name: &'static CStr, @@ -61,7 +74,7 @@ unsafe fn register( (*udrv.get()).name = name.as_char_ptr(); (*udrv.get()).probe = Some(Self::probe_callback); (*udrv.get()).disconnect = Some(Self::disconnect_callback); - (*udrv.get()).id_table = T::ID_TABLE.as_ptr(); + (*udrv.get()).id_table = <F::Of<'static> as Driver<'static>>::ID_TABLE.as_ptr(); } // SAFETY: `udrv` is guaranteed to be a valid `DriverType`. @@ -76,7 +89,11 @@ unsafe fn unregister(udrv: &Opaque<Self::DriverType>) { } } -impl<T: Driver + 'static> Adapter<T> { +impl<F> Adapter<F> +where + F: ForLt + 'static, + for<'bound> F::Of<'bound>: Driver<'bound>, +{ extern "C" fn probe_callback( intf: *mut bindings::usb_interface, id: *const bindings::usb_device_id, @@ -87,16 +104,16 @@ extern "C" fn probe_callback( // INVARIANT: `intf` is valid for the duration of `probe_callback()`. let intf = unsafe { &*intf.cast::<Interface<device::CoreInternal>>() }; - from_result(|| { - // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct usb_device_id` and - // does not add additional invariants, so it's safe to transmute. - let id = unsafe { &*id.cast::<DeviceId>() }; + // SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `struct usb_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()); - let data = T::probe(intf, id, info); + from_result(|| { + let info = <F::Of<'_> as Driver<'_>>::ID_TABLE.info(id.index()); + let data = <F::Of<'_> as Driver<'_>>::probe(intf, id, info); let dev: &device::Device<device::CoreInternal> = intf.as_ref(); - dev.set_drvdata::<ForLt!(T)>(data)?; + dev.set_drvdata::<F>(data)?; Ok(0) }) } @@ -111,11 +128,10 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) { let dev: &device::Device<device::CoreInternal> = intf.as_ref(); // 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_borrow::<ForLt!(T)>() }; + // `probe_callback`, hence it's guaranteed that drvdata has been set. + let data = unsafe { dev.drvdata_borrow::<F>() }; - T::disconnect(intf, data); + <F::Of<'_> as Driver<'_>>::disconnect(intf, data); } } @@ -281,29 +297,29 @@ macro_rules! usb_device_table { /// kernel::usb_device_table!( /// USB_TABLE, /// MODULE_USB_TABLE, -/// <MyDriver as usb::Driver>::IdInfo, +/// <MyDriver as usb::Driver<'_>>::IdInfo, /// [ /// (usb::DeviceId::from_id(0x1234, 0x5678), ()), /// (usb::DeviceId::from_id(0xabcd, 0xef01), ()), /// ] /// ); /// -/// impl usb::Driver for MyDriver { +/// impl<'bound> usb::Driver<'bound> for MyDriver { /// type IdInfo = (); /// const ID_TABLE: usb::IdTable<Self::IdInfo> = &USB_TABLE; /// /// fn probe( -/// _interface: &usb::Interface<Core>, -/// _id: &usb::DeviceId, -/// _info: &Self::IdInfo, -/// ) -> impl PinInit<Self, Error> { +/// _interface: &'bound usb::Interface<Core>, +/// _id: &'bound usb::DeviceId, +/// _info: &'bound Self::IdInfo, +/// ) -> impl PinInit<Self, Error> + 'bound { /// Err(ENODEV) /// } /// -/// fn disconnect(_interface: &usb::Interface<Core>, _data: Pin<&Self>) {} +/// fn disconnect(_interface: &'bound usb::Interface<Core>, _data: Pin<&'bound Self>) {} /// } ///``` -pub trait Driver { +pub trait Driver<'bound> { /// The type holding information about each one of the device ids supported by the driver. type IdInfo: 'static; @@ -315,15 +331,15 @@ 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>, - id: &DeviceId, - id_info: &Self::IdInfo, - ) -> impl PinInit<Self, Error>; + interface: &'bound Interface<device::Core>, + id: &'bound DeviceId, + id_info: &'bound Self::IdInfo, + ) -> impl PinInit<Self, 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>); + fn disconnect(interface: &'bound Interface<device::Core>, data: Pin<&'bound Self>); } /// A USB interface. @@ -486,7 +502,10 @@ unsafe impl Sync for Device<device::Bound> {} /// ``` #[macro_export] macro_rules! module_usb_driver { - ($($f:tt)*) => { - $crate::module_driver!(<T>, $crate::usb::Adapter<T>, { $($f)* }); + (type: $type:ty, $($rest:tt)*) => { + $crate::module_driver!(<T>, $crate::usb::Adapter<T>, { + type: $crate::types::ForLt!($type), + $($rest)* + }); } } diff --git a/samples/rust/rust_driver_usb.rs b/samples/rust/rust_driver_usb.rs index ab72e99e1274..271aaf415795 100644 --- a/samples/rust/rust_driver_usb.rs +++ b/samples/rust/rust_driver_usb.rs @@ -20,26 +20,26 @@ struct SampleDriver { kernel::usb_device_table!( USB_TABLE, MODULE_USB_TABLE, - <SampleDriver as usb::Driver>::IdInfo, + <SampleDriver as usb::Driver<'_>>::IdInfo, [(usb::DeviceId::from_id(0x1234, 0x5678), ()),] ); -impl usb::Driver for SampleDriver { +impl<'bound> usb::Driver<'bound> for SampleDriver { type IdInfo = (); const ID_TABLE: usb::IdTable<Self::IdInfo> = &USB_TABLE; fn probe( - intf: &usb::Interface<Core>, - _id: &usb::DeviceId, - _info: &Self::IdInfo, - ) -> impl PinInit<Self, Error> { + intf: &'bound usb::Interface<Core>, + _id: &'bound usb::DeviceId, + _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(intf: &'bound usb::Interface<Core>, _data: Pin<&'bound Self>) { let dev: &device::Device<Core> = intf.as_ref(); dev_info!(dev, "Rust USB driver sample disconnected\n"); } -- 2.54.0
