Commit a69dc41a authored by Alice Ryhl's avatar Alice Ryhl Committed by Greg Kroah-Hartman
Browse files

rust: types: add Opaque::try_ffi_init 



This will be used by the miscdevice abstractions, as the C function
`misc_register` is fallible.

Signed-off-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarBenno Lossin <benno.lossin@proton.me>
Reviewed-by: default avatarFiona Behrens <me@kloenk.dev>
Link: https://lore.kernel.org/r/20241001-b4-miscdevice-v2-1-330d760041fa@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8cf0b939

rust/kernel/types.rs

+16 −0
Original line number Diff line number Diff line
@@ -299,6 +299,22 @@ pub fn ffi_init(init_func: impl FnOnce(*mut T)) -> impl PinInit<Self> { 
        }

    }



    /// Creates a fallible pin-initializer from the given initializer closure.

    ///

    /// The returned initializer calls the given closure with the pointer to the inner `T` of this

    /// `Opaque`. Since this memory is uninitialized, the closure is not allowed to read from it.

    ///

    /// This function is safe, because the `T` inside of an `Opaque` is allowed to be

    /// uninitialized. Additionally, access to the inner `T` requires `unsafe`, so the caller needs

    /// to verify at that point that the inner value is valid.

    pub fn try_ffi_init<E>(

        init_func: impl FnOnce(*mut T) -> Result<(), E>,

    ) -> impl PinInit<Self, E> {

        // SAFETY: We contain a `MaybeUninit`, so it is OK for the `init_func` to not fully

        // initialize the `T`.

        unsafe { init::pin_init_from_closure::<_, E>(move |slot| init_func(Self::raw_get(slot))) }

    }



    /// Returns a raw pointer to the opaque data.

    pub const fn get(&self) -> *mut T {

        UnsafeCell::get(&self.value).cast::<T>()