Commit 47e6715b authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

rust: device: implement Device::as_bound() 



Provide an unsafe functions for abstractions to convert a regular
&Device to a &Device<Bound>.

This is useful for registrations that provide certain guarantees for the
scope of their callbacks, such as IRQs or certain class device
registrations (e.g. PWM, miscdevice).

Reviewed-by: default avatarBenno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250713182737.64448-2-dakr@kernel.org


[ Remove unnecessary cast(). - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 85aa5b16

rust/kernel/device.rs

+19 −0
Original line number Diff line number Diff line
@@ -60,6 +60,25 @@ pub unsafe fn get_device(ptr: *mut bindings::device) -> ARef<Self> { 
        // SAFETY: By the safety requirements ptr is valid

        unsafe { Self::as_ref(ptr) }.into()

    }



    /// Convert a [`&Device`](Device) into a [`&Device<Bound>`](Device<Bound>).

    ///

    /// # Safety

    ///

    /// The caller is responsible to ensure that the returned [`&Device<Bound>`](Device<Bound>)

    /// only lives as long as it can be guaranteed that the [`Device`] is actually bound.

    pub unsafe fn as_bound(&self) -> &Device<Bound> {

        let ptr = core::ptr::from_ref(self);



        // CAST: By the safety requirements the caller is responsible to guarantee that the

        // returned reference only lives as long as the device is actually bound.

        let ptr = ptr.cast();



        // SAFETY:

        // - `ptr` comes from `from_ref(self)` above, hence it's guaranteed to be valid.

        // - Any valid `Device` pointer is also a valid pointer for `Device<Bound>`.

        unsafe { &*ptr }

    }

}



impl Device<CoreInternal> {