Messages in this thread | | | Date | Wed, 29 Mar 2023 11:55:01 -0300 | Subject | Re: [PATCH v2 6/6] rust: error: Add from_result() helper | From | Martin Rodriguez Reboredo <> |
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On 3/29/23 09:04, Asahi Lina wrote: > [...] > > + > +/// Calls a closure returning a [`crate::error::Result<T>`] and converts the result to > +/// a C integer result. > +/// > +/// This is useful when calling Rust functions that return [`crate::error::Result<T>`] > +/// from inside `extern "C"` functions that need to return an integer error result. > +/// > +/// `T` should be convertible from an `i16` via `From<i16>`. > +/// > +/// # Examples > +/// > +/// ```ignore > +/// # use kernel::from_result; > +/// # use kernel::bindings; > +/// unsafe extern "C" fn probe_callback( > +/// pdev: *mut bindings::platform_device, > +/// ) -> core::ffi::c_int { > +/// from_result(|| { > +/// let ptr = devm_alloc(pdev)?; > +/// bindings::platform_set_drvdata(pdev, ptr); > +/// Ok(0) > +/// }) > +/// } > +/// ``` > +// TODO: Remove `dead_code` marker once an in-kernel client is available. > +#[allow(dead_code)] > +pub(crate) fn from_result<T, F>(f: F) -> T > +where > + T: From<i16>, > + F: FnOnce() -> Result<T>, > +{ > + match f() { > + Ok(v) => v, > + // NO-OVERFLOW: negative `errno`s are no smaller than `-bindings::MAX_ERRNO`, > + // `-bindings::MAX_ERRNO` fits in an `i16` as per invariant above, > + // therefore a negative `errno` always fits in an `i16` and will not overflow. > + Err(e) => T::from(e.to_errno() as i16), > + } > +} >
Reviewed-by: Martin Rodriguez Reboredo
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