Wedson Almeida Filhorust: add `container_of!` macroe9441712 years agoHistory
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// SPDX-License-Identifier: GPL-2.0 //! The `kernel` crate.//!//! This crate contains the kernel APIs that have been ported or wrapped for//! usage by Rust code in the kernel and is shared by all of them.//!//! In other words, all the rest of the Rust code in the kernel (e.g. kernel//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.//!//! If you need a kernel C API that is not ported or wrapped yet here, then//! do so first instead of bypassing this crate. #![no_std]#![feature(allocator_api)]#![feature(coerce_unsized)]#![feature(dispatch_from_dyn)]#![feature(new_uninit)]#![feature(offset_of)]#![feature(receiver_trait)]#![feature(unsize)] // Ensure conditional compilation based on the kernel configuration works;// otherwise we may silently break things like initcall handling.#[cfg(not(CONFIG_RUST))]compile_error!("Missing kernel configuration for conditional compilation"); // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).extern crate self as kernel; #[cfg(not(test))]#[cfg(not(testlib))]mod allocator;mod build_assert;pub mod error;pub mod init;pub mod ioctl;#[cfg(CONFIG_KUNIT)]pub mod kunit;#[cfg(CONFIG_NET)]pub mod net;pub mod prelude;pub mod print;mod static_assert;#[doc(hidden)]pub mod std_vendor;pub mod str;pub mod sync;pub mod task;pub mod time;pub mod types;pub mod workqueue; #[doc(hidden)]pub use bindings;pub use macros;pub use uapi; #[doc(hidden)]pub use build_error::build_error; /// Prefix to appear before log messages printed from within the `kernel` crate.const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; /// The top level entrypoint to implementing a kernel module.////// For any teardown or cleanup operations, your type may implement [`Drop`].pub trait Module: Sized + Sync {    /// Called at module initialization time.    ///    /// Use this method to perform whatever setup or registration your module    /// should do.    ///    /// Equivalent to the `module_init` macro in the C API.    fn init(module: &'static ThisModule) -> error::Result<Self>;} /// Equivalent to `THIS_MODULE` in the C API.////// C header: [`include/linux/export.h`](srctree/include/linux/export.h)pub struct ThisModule(*mut bindings::module); // SAFETY: `THIS_MODULE` may be used from all threads within a module.unsafe impl Sync for ThisModule {} impl ThisModule {    /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.    ///    /// # Safety    ///    /// The pointer must be equal to the right `THIS_MODULE`.    pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {        ThisModule(ptr)    }} #[cfg(not(any(testlib, test)))]#[panic_handler]fn panic(info: &core::panic::PanicInfo<'_>) -> ! {    pr_emerg!("{}\n", info);    // SAFETY: FFI call.    unsafe { bindings::BUG() };} /// Produces a pointer to an object from a pointer to one of its fields.////// # Safety////// The pointer passed to this macro, and the pointer returned by this macro, must both be in/// bounds of the same allocation.////// # Examples////// ```/// # use kernel::container_of;/// struct Test {///     a: u64,///     b: u32,/// }////// let test = Test { a: 10, b: 20 };/// let b_ptr = &test.b;/// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be/// // in-bounds of the same allocation as `b_ptr`./// let test_alias = unsafe { container_of!(b_ptr, Test, b) };/// assert!(core::ptr::eq(&test, test_alias));/// ```#[macro_export]macro_rules! container_of {    ($ptr:expr, $type:ty, $($f:tt)*) => {{        let ptr = $ptr as *const _ as *const u8;        let offset: usize = ::core::mem::offset_of!($type, $($f)*);        ptr.sub(offset) as *const $type    }}}