Merge tag 'ceph-for-6.2-rc1' of https://github.com/ceph/ceph-client

[platform/kernel/linux-starfive.git] / rust / macros / lib.rs

diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
index 91764bf..c1d385e 100644 (file)
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -2,8 +2,10 @@
 
 //! Crate for all kernel procedural macros.
 
+mod concat_idents;
 mod helpers;
 mod module;
+mod vtable;
 
 use proc_macro::TokenStream;
 
@@ -23,20 +25,20 @@ use proc_macro::TokenStream;
 ///
 /// module!{
 ///     type: MyModule,
-///     name: b"my_kernel_module",
-///     author: b"Rust for Linux Contributors",
-///     description: b"My very own kernel module!",
-///     license: b"GPL",
+///     name: "my_kernel_module",
+///     author: "Rust for Linux Contributors",
+///     description: "My very own kernel module!",
+///     license: "GPL",
 ///     params: {
 ///        my_i32: i32 {
 ///            default: 42,
 ///            permissions: 0o000,
-///            description: b"Example of i32",
+///            description: "Example of i32",
 ///        },
 ///        writeable_i32: i32 {
 ///            default: 42,
 ///            permissions: 0o644,
-///            description: b"Example of i32",
+///            description: "Example of i32",
 ///        },
 ///    },
 /// }
@@ -70,3 +72,97 @@ use proc_macro::TokenStream;
 pub fn module(ts: TokenStream) -> TokenStream {
     module::module(ts)
 }
+
+/// Declares or implements a vtable trait.
+///
+/// Linux's use of pure vtables is very close to Rust traits, but they differ
+/// in how unimplemented functions are represented. In Rust, traits can provide
+/// default implementation for all non-required methods (and the default
+/// implementation could just return `Error::EINVAL`); Linux typically use C
+/// `NULL` pointers to represent these functions.
+///
+/// This attribute is intended to close the gap. Traits can be declared and
+/// implemented with the `#[vtable]` attribute, and a `HAS_*` associated constant
+/// will be generated for each method in the trait, indicating if the implementor
+/// has overridden a method.
+///
+/// This attribute is not needed if all methods are required.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// // Declares a `#[vtable]` trait
+/// #[vtable]
+/// pub trait Operations: Send + Sync + Sized {
+///     fn foo(&self) -> Result<()> {
+///         Err(EINVAL)
+///     }
+///
+///     fn bar(&self) -> Result<()> {
+///         Err(EINVAL)
+///     }
+/// }
+///
+/// struct Foo;
+///
+/// // Implements the `#[vtable]` trait
+/// #[vtable]
+/// impl Operations for Foo {
+///     fn foo(&self) -> Result<()> {
+/// #        Err(EINVAL)
+///         // ...
+///     }
+/// }
+///
+/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
+/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
+/// ```
+#[proc_macro_attribute]
+pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
+    vtable::vtable(attr, ts)
+}
+
+/// Concatenate two identifiers.
+///
+/// This is useful in macros that need to declare or reference items with names
+/// starting with a fixed prefix and ending in a user specified name. The resulting
+/// identifier has the span of the second argument.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::macro::concat_idents;
+///
+/// macro_rules! pub_no_prefix {
+///     ($prefix:ident, $($newname:ident),+) => {
+///         $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
+///     };
+/// }
+///
+/// pub_no_prefix!(
+///     binder_driver_return_protocol_,
+///     BR_OK,
+///     BR_ERROR,
+///     BR_TRANSACTION,
+///     BR_REPLY,
+///     BR_DEAD_REPLY,
+///     BR_TRANSACTION_COMPLETE,
+///     BR_INCREFS,
+///     BR_ACQUIRE,
+///     BR_RELEASE,
+///     BR_DECREFS,
+///     BR_NOOP,
+///     BR_SPAWN_LOOPER,
+///     BR_DEAD_BINDER,
+///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
+///     BR_FAILED_REPLY
+/// );
+///
+/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
+/// ```
+#[proc_macro]
+pub fn concat_idents(ts: TokenStream) -> TokenStream {
+    concat_idents::concat_idents(ts)
+}