Make auxiliary::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_auxiliary_driver! wraps the driver type in ForLt!() so drivers don't have to. Signed-off-by: Danilo Krummrich <[email protected]> --- drivers/gpu/drm/nova/driver.rs | 9 ++-- rust/kernel/auxiliary.rs | 60 ++++++++++++++++++--------- samples/rust/rust_driver_auxiliary.rs | 12 ++++-- 3 files changed, 55 insertions(+), 26 deletions(-) diff --git a/drivers/gpu/drm/nova/driver.rs b/drivers/gpu/drm/nova/driver.rs index b1af0a099551..8e28ccad0575 100644 --- a/drivers/gpu/drm/nova/driver.rs +++ b/drivers/gpu/drm/nova/driver.rs @@ -42,18 +42,21 @@ pub(crate) struct NovaData { kernel::auxiliary_device_table!( AUX_TABLE, MODULE_AUX_TABLE, - <NovaDriver as auxiliary::Driver>::IdInfo, + <NovaDriver as auxiliary::Driver<'_>>::IdInfo, [( auxiliary::DeviceId::new(NOVA_CORE_MODULE_NAME, AUXILIARY_NAME), () )] ); -impl auxiliary::Driver for NovaDriver { +impl<'bound> auxiliary::Driver<'bound> for NovaDriver { type IdInfo = (); const ID_TABLE: auxiliary::IdTable<Self::IdInfo> = &AUX_TABLE; - fn probe(adev: &auxiliary::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> { + fn probe( + adev: &'bound auxiliary::Device<Core>, + _info: &'bound Self::IdInfo, + ) -> impl PinInit<Self, Error> + 'bound { let data = try_pin_init!(NovaData { adev: adev.into() }); let drm = drm::Device::<Self>::new(adev.as_ref(), data)?; diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs index e193ba5b7167..d2785a841380 100644 --- a/rust/kernel/auxiliary.rs +++ b/rust/kernel/auxiliary.rs @@ -38,22 +38,35 @@ }; /// An adapter for the registration of auxiliary 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_auxiliary_driver!` +/// generates this automatically via `ForLt!()`. +pub struct Adapter<F>(PhantomData<F>); // SAFETY: // - `bindings::auxiliary_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 auxiliary_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::auxiliary_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( adrv: &Opaque<Self::DriverType>, name: &'static CStr, @@ -64,7 +77,7 @@ unsafe fn register( (*adrv.get()).name = name.as_char_ptr(); (*adrv.get()).probe = Some(Self::probe_callback); (*adrv.get()).remove = Some(Self::remove_callback); - (*adrv.get()).id_table = T::ID_TABLE.as_ptr(); + (*adrv.get()).id_table = <F::Of<'static> as Driver<'static>>::ID_TABLE.as_ptr(); } // SAFETY: `adrv` is guaranteed to be a valid `DriverType`. @@ -79,7 +92,11 @@ unsafe fn unregister(adrv: &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( adev: *mut bindings::auxiliary_device, id: *const bindings::auxiliary_device_id, @@ -93,12 +110,12 @@ extern "C" fn probe_callback( // SAFETY: `DeviceId` is a `#[repr(transparent)`] wrapper of `struct auxiliary_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()); from_result(|| { - let data = T::probe(adev, info); + let info = <F::Of<'_> as Driver<'_>>::ID_TABLE.info(id.index()); + let data = <F::Of<'_> as Driver<'_>>::probe(adev, info); - adev.as_ref().set_drvdata::<ForLt!(T)>(data)?; + adev.as_ref().set_drvdata::<F>(data)?; Ok(0) }) } @@ -111,19 +128,21 @@ extern "C" fn remove_callback(adev: *mut bindings::auxiliary_device) { let adev = unsafe { &*adev.cast::<Device<device::CoreInternal>>() }; // 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 { adev.as_ref().drvdata_borrow::<ForLt!(T)>() }; + // `probe_callback`, hence it's guaranteed that drvdata has been set. + let data = unsafe { adev.as_ref().drvdata_borrow::<F>() }; - T::unbind(adev, data); + <F::Of<'_> as Driver<'_>>::unbind(adev, data); } } /// Declares a kernel module that exposes a single auxiliary driver. #[macro_export] macro_rules! module_auxiliary_driver { - ($($f:tt)*) => { - $crate::module_driver!(<T>, $crate::auxiliary::Adapter<T>, { $($f)* }); + (type: $type:ty, $($rest:tt)*) => { + $crate::module_driver!(<T>, $crate::auxiliary::Adapter<T>, { + type: $crate::types::ForLt!($type), + $($rest)* + }); }; } @@ -195,7 +214,7 @@ macro_rules! auxiliary_device_table { /// The auxiliary driver trait. /// /// Drivers must implement this trait in order to get an auxiliary driver registered. -pub trait Driver { +pub trait Driver<'bound>: Send { /// The type holding information about each device id supported by the driver. /// /// TODO: Use associated_type_defaults once stabilized: @@ -209,7 +228,10 @@ pub trait Driver { /// Auxiliary driver probe. /// /// Called when an auxiliary device is matches a corresponding driver. - fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo) -> impl PinInit<Self, Error>; + fn probe( + dev: &'bound Device<device::Core>, + id_info: &'bound Self::IdInfo, + ) -> impl PinInit<Self, Error> + 'bound; /// Auxiliary driver unbind. /// @@ -221,7 +243,7 @@ pub trait Driver { /// operations to gracefully tear down the device. /// /// Otherwise, release operations for driver resources should be performed in `Self::drop`. - fn unbind(dev: &Device<device::Core>, this: Pin<&Self>) { + fn unbind(dev: &'bound Device<device::Core>, this: Pin<&'bound Self>) { let _ = (dev, this); } } diff --git a/samples/rust/rust_driver_auxiliary.rs b/samples/rust/rust_driver_auxiliary.rs index a1b42d30580e..6baeb1dde5da 100644 --- a/samples/rust/rust_driver_auxiliary.rs +++ b/samples/rust/rust_driver_auxiliary.rs @@ -26,16 +26,19 @@ kernel::auxiliary_device_table!( AUX_TABLE, MODULE_AUX_TABLE, - <AuxiliaryDriver as auxiliary::Driver>::IdInfo, + <AuxiliaryDriver as auxiliary::Driver<'_>>::IdInfo, [(auxiliary::DeviceId::new(MODULE_NAME, AUXILIARY_NAME), ())] ); -impl auxiliary::Driver for AuxiliaryDriver { +impl<'bound> auxiliary::Driver<'bound> for AuxiliaryDriver { type IdInfo = (); const ID_TABLE: auxiliary::IdTable<Self::IdInfo> = &AUX_TABLE; - fn probe(adev: &auxiliary::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> { + fn probe( + adev: &'bound auxiliary::Device<Core>, + _info: &'bound Self::IdInfo, + ) -> impl PinInit<Self, Error> + 'bound { dev_info!( adev, "Probing auxiliary driver for auxiliary device with id={}\n", @@ -123,7 +126,8 @@ struct SampleModule { #[allow(clippy::type_complexity)] _pci_driver: driver::Registration<pci::Adapter<ForLt!(ParentDriver)>>, #[pin] - _aux_driver: driver::Registration<auxiliary::Adapter<AuxiliaryDriver>>, + #[allow(clippy::type_complexity)] + _aux_driver: driver::Registration<auxiliary::Adapter<ForLt!(AuxiliaryDriver)>>, } impl InPlaceModule for SampleModule { -- 2.54.0
