// SPDX-License-Identifier: GPL-2.0 //! Kernel errors.//!//! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h) use alloc::collections::TryReserveError; /// Contains the C-compatible error codes.pub mod code {    /// Out of memory.    pub const ENOMEM: super::Error = super::Error(-(crate::bindings::ENOMEM as i32));} /// Generic integer kernel error.////// The kernel defines a set of integer generic error codes based on C and/// POSIX ones. These codes may have a more specific meaning in some contexts.////// # Invariants////// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`).#[derive(Clone, Copy, PartialEq, Eq)]pub struct Error(core::ffi::c_int); impl Error {    /// Returns the kernel error code.    pub fn to_kernel_errno(self) -> core::ffi::c_int {        self.0    }} impl From<TryReserveError> for Error {    fn from(_: TryReserveError) -> Error {        code::ENOMEM    }} /// A [`Result`] with an [`Error`] error type.////// To be used as the return type for functions that may fail.////// # Error codes in C and Rust////// In C, it is common that functions indicate success or failure through/// their return value; modifying or returning extra data through non-`const`/// pointer parameters. In particular, in the kernel, functions that may fail/// typically return an `int` that represents a generic error code. We model/// those as [`Error`].////// In Rust, it is idiomatic to model functions that may fail as returning/// a [`Result`]. Since in the kernel many functions return an error code,/// [`Result`] is a type alias for a [`core::result::Result`] that uses/// [`Error`] as its error type.////// Note that even if a function does not return anything when it succeeds,/// it should still be modeled as returning a `Result` rather than/// just an [`Error`].pub type Result<T = ()> = core::result::Result<T, Error>;