Implement `configfs_attrs!` as a procedural macro using `syn`, this improves readability and maintainability. Remove the old macro and replace all uses with the new macro. Add the new macro implementation file to MAINTAINERS. Signed-off-by: Malte Wechter --- MAINTAINERS | 1 + drivers/block/rnull/configfs.rs | 2 +- rust/kernel/configfs.rs | 251 ---------------------------------------- rust/macros/configfs_attrs.rs | 182 +++++++++++++++++++++++++++++ rust/macros/lib.rs | 85 ++++++++++++++ samples/rust/rust_configfs.rs | 2 +- 6 files changed, 270 insertions(+), 253 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 2fb1c75afd163..45f7a1ec93b45 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6464,6 +6464,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/a.hindborg/linux.git config F: fs/configfs/ F: include/linux/configfs.h F: rust/kernel/configfs.rs +F: rust/macros/configfs_attrs.rs F: samples/configfs/ F: samples/rust/rust_configfs.rs diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs index 7c2eb5c0b7228..f28ec69d79846 100644 --- a/drivers/block/rnull/configfs.rs +++ b/drivers/block/rnull/configfs.rs @@ -4,8 +4,8 @@ use kernel::{ block::mq::gen_disk::{GenDisk, GenDiskBuilder}, configfs::{self, AttributeOperations}, - configfs_attrs, fmt::{self, Write as _}, + macros::configfs_attrs, new_mutex, page::PAGE_SIZE, prelude::*, diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs index 2339c6467325d..7a91e36677f52 100644 --- a/rust/kernel/configfs.rs +++ b/rust/kernel/configfs.rs @@ -791,254 +791,3 @@ fn as_ptr(&self) -> *const bindings::config_item_type { self.item_type.get() } } - -/// Define a list of configfs attributes statically. -/// -/// Invoking the macro in the following manner: -/// -/// ```ignore -/// let item_type = configfs_attrs! { -/// container: configfs::Subsystem, -/// data: Configuration, -/// child: Child, -/// attributes: [ -/// message: 0, -/// bar: 1, -/// ], -/// }; -/// ``` -/// -/// Expands the following output: -/// -/// ```ignore -/// let item_type = { -/// static CONFIGURATION_MESSAGE_ATTR: kernel::configfs::Attribute< -/// 0, -/// Configuration, -/// Configuration, -/// > = unsafe { -/// kernel::configfs::Attribute::new({ -/// const S: &str = "message\u{0}"; -/// const C: &kernel::str::CStr = match kernel::str::CStr::from_bytes_with_nul( -/// S.as_bytes() -/// ) { -/// Ok(v) => v, -/// Err(_) => { -/// core::panicking::panic_fmt(core::const_format_args!( -/// "string contains interior NUL" -/// )); -/// } -/// }; -/// C -/// }) -/// }; -/// -/// static CONFIGURATION_BAR_ATTR: kernel::configfs::Attribute< -/// 1, -/// Configuration, -/// Configuration -/// > = unsafe { -/// kernel::configfs::Attribute::new({ -/// const S: &str = "bar\u{0}"; -/// const C: &kernel::str::CStr = match kernel::str::CStr::from_bytes_with_nul( -/// S.as_bytes() -/// ) { -/// Ok(v) => v, -/// Err(_) => { -/// core::panicking::panic_fmt(core::const_format_args!( -/// "string contains interior NUL" -/// )); -/// } -/// }; -/// C -/// }) -/// }; -/// -/// const N: usize = (1usize + (1usize + 0usize)) + 1usize; -/// -/// static CONFIGURATION_ATTRS: kernel::configfs::AttributeList = -/// unsafe { kernel::configfs::AttributeList::new() }; -/// -/// { -/// const N: usize = 0usize; -/// unsafe { CONFIGURATION_ATTRS.add::(&CONFIGURATION_MESSAGE_ATTR) }; -/// } -/// -/// { -/// const N: usize = (1usize + 0usize); -/// unsafe { CONFIGURATION_ATTRS.add::(&CONFIGURATION_BAR_ATTR) }; -/// } -/// -/// static CONFIGURATION_TPE: -/// kernel::configfs::ItemType ,Configuration> -/// = kernel::configfs::ItemType::< -/// configfs::Subsystem, -/// Configuration -/// >::new_with_child_ctor::( -/// &THIS_MODULE, -/// &CONFIGURATION_ATTRS -/// ); -/// -/// &CONFIGURATION_TPE -/// } -/// ``` -#[macro_export] -macro_rules! configfs_attrs { - ( - container: $container:ty, - data: $data:ty, - attributes: [ - $($name:ident: $attr:literal),* $(,)? - ] $(,)? - ) => { - $crate::configfs_attrs!( - count: - @container($container), - @data($data), - @child(), - @no_child(x), - @attrs($($name $attr)*), - @eat($($name $attr,)*), - @assign(), - @cnt(0usize), - ) - }; - ( - container: $container:ty, - data: $data:ty, - child: $child:ty, - attributes: [ - $($name:ident: $attr:literal),* $(,)? - ] $(,)? - ) => { - $crate::configfs_attrs!( - count: - @container($container), - @data($data), - @child($child), - @no_child(), - @attrs($($name $attr)*), - @eat($($name $attr,)*), - @assign(), - @cnt(0usize), - ) - }; - (count: - @container($container:ty), - @data($data:ty), - @child($($child:ty)?), - @no_child($($no_child:ident)?), - @attrs($($aname:ident $aattr:literal)*), - @eat($name:ident $attr:literal, $($rname:ident $rattr:literal,)*), - @assign($($assign:block)*), - @cnt($cnt:expr), - ) => { - $crate::configfs_attrs!( - count: - @container($container), - @data($data), - @child($($child)?), - @no_child($($no_child)?), - @attrs($($aname $aattr)*), - @eat($($rname $rattr,)*), - @assign($($assign)* { - const N: usize = $cnt; - // The following macro text expands to a call to `Attribute::add`. - - // SAFETY: By design of this macro, the name of the variable we - // invoke the `add` method on below, is not visible outside of - // the macro expansion. The macro does not operate concurrently - // on this variable, and thus we have exclusive access to the - // variable. - unsafe { - $crate::macros::paste!( - [< $data:upper _ATTRS >] - .add::(&[< $data:upper _ $name:upper _ATTR >]) - ) - }; - }), - @cnt(1usize + $cnt), - ) - }; - (count: - @container($container:ty), - @data($data:ty), - @child($($child:ty)?), - @no_child($($no_child:ident)?), - @attrs($($aname:ident $aattr:literal)*), - @eat(), - @assign($($assign:block)*), - @cnt($cnt:expr), - ) => - { - $crate::configfs_attrs!( - final: - @container($container), - @data($data), - @child($($child)?), - @no_child($($no_child)?), - @attrs($($aname $aattr)*), - @assign($($assign)*), - @cnt($cnt), - ) - }; - (final: - @container($container:ty), - @data($data:ty), - @child($($child:ty)?), - @no_child($($no_child:ident)?), - @attrs($($name:ident $attr:literal)*), - @assign($($assign:block)*), - @cnt($cnt:expr), - ) => - { - $crate::macros::paste!{ - { - $( - // SAFETY: We are expanding `configfs_attrs`. - static [< $data:upper _ $name:upper _ATTR >]: - $crate::configfs::Attribute<$attr, $data, $data> = - unsafe { - $crate::configfs::Attribute::new( - $crate::c_str!(::core::stringify!($name)), - ) - }; - )* - - - // We need space for a null terminator. - const N: usize = $cnt + 1usize; - - // SAFETY: We are expanding `configfs_attrs`. - static [< $data:upper _ATTRS >]: - $crate::configfs::AttributeList = - unsafe { $crate::configfs::AttributeList::new() }; - - $($assign)* - - $( - const [<$no_child:upper>]: bool = true; - - static [< $data:upper _TPE >] : $crate::configfs::ItemType<$container, $data> = - $crate::configfs::ItemType::<$container, $data>::new::( - &THIS_MODULE, &[<$ data:upper _ATTRS >] - ); - )? - - $( - static [< $data:upper _TPE >]: - $crate::configfs::ItemType<$container, $data> = - $crate::configfs::ItemType::<$container, $data>:: - new_with_child_ctor::( - &THIS_MODULE, &[<$ data:upper _ATTRS >] - ); - )? - - & [< $data:upper _TPE >] - } - } - }; - -} - -pub use crate::configfs_attrs; diff --git a/rust/macros/configfs_attrs.rs b/rust/macros/configfs_attrs.rs new file mode 100644 index 0000000000000..f5c3a8d9bffbd --- /dev/null +++ b/rust/macros/configfs_attrs.rs @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0 + +use quote::{ + quote, // + ToTokens, +}; + +use proc_macro2::{ + Span, // +}; + +use syn::{ + bracketed, + parse::{ + Parse, + ParseStream, // + }, + punctuated::Punctuated, + spanned::Spanned, + Ident, + LitInt, + Token, + Type, // +}; + +pub(crate) struct ConfigfsAttrs { + container: Type, + data: Type, + child: Option, + attributes: Vec<(Ident, LitInt)>, +} + +fn parse_attribute_field(stream: ParseStream<'_>) -> syn::Result<(Ident, LitInt)> { + let id = stream.parse::()?; + let _colon = stream.parse::()?; + let v = stream.parse::()?; + Ok((id, v)) +} + +fn parse_named_field(stream: ParseStream<'_>, name: &str) -> syn::Result { + let try_stream = stream.fork(); + let name_id = try_stream.parse::()?; + if name_id != name { + return Err(parse_field_error(name_id.span(), &name_id, name)); + } + let _name_id = stream.parse::()?; + let _colon = stream.parse::()?; + let v = stream.parse::()?; + stream.parse::()?; + Ok(v) +} + +fn parse_attributes(stream: ParseStream<'_>) -> syn::Result> { + let attribute_id = stream.parse::()?; + if attribute_id != "attributes" { + return Err(syn::Error::new( + attribute_id.span(), + format!( + "unexpected identifier: {}, expected: 'attributes'", + attribute_id + ), + )); + } + stream.parse::()?; + let attr_stream; + let _bracket = bracketed!(attr_stream in stream); + let attributes = Punctuated::<(Ident, LitInt), Token![,]>::parse_terminated_with( + &attr_stream, + parse_attribute_field, + )?; + let attributes = attributes.into_iter().collect::>(); + + stream.parse::>()?; + Ok(attributes) +} + +fn parse_field_error(span: Span, name: &Ident, expected_name: &str) -> syn::Error { + syn::Error::new( + span, + format!("Unexpected field name, got: {name} expected: {expected_name}"), + ) +} + +impl Parse for ConfigfsAttrs { + fn parse(input: ParseStream<'_>) -> syn::Result { + let container = parse_named_field(input, "container")?; + let data = parse_named_field(input, "data")?; + let child = parse_named_field(input, "child").ok(); + let attributes = parse_attributes(input)?; + + Ok(ConfigfsAttrs { + container, + data, + child, + attributes, + }) + } +} + +fn make_static_ident(ty: &T, suffix: &str) -> syn::Ident { + let raw_id = quote! { #ty }.to_string(); + + // Sanitizing syn::Type::Path, this is safe since it is + // only used as the identifier. + let normalized = raw_id + .split("::") + .map(|s| String::from(s.trim())) + .reduce(|a, b| format!("{a}_{b}")) + .expect("Cannot be empty") + .to_uppercase() + .replace(|c: char| !c.is_alphanumeric(), "_"); + + Ident::new(&format!("{}_{}", normalized, suffix), ty.span()) +} + +pub(crate) fn configfs_attrs(cfs_attrs: ConfigfsAttrs) -> proc_macro2::TokenStream { + let (container_ty, data_ty) = (&cfs_attrs.container, &cfs_attrs.data); + + let data_tp_ident = make_static_ident(data_ty, "TPE"); + let data_attr_ident = make_static_ident(data_ty, "ATTR_LIST"); + + let n = cfs_attrs.attributes.len() + 1; + + let attr_list = quote! { + static #data_attr_ident: kernel::configfs::AttributeList<#n, #data_ty> = + // SAFETY: We are expanding `configfs_attrs`. + unsafe { kernel::configfs::AttributeList::new() }; + }; + + let mut attrs = Vec::new(); + for (attr_idx, (name, id)) in cfs_attrs.attributes.iter().enumerate() { + let name_with_attr = make_static_ident(name, "ATTR"); + + let id: u64 = match id.base10_parse::() { + Ok(v) => v, + Err(_) => { + return syn::Error::new(id.span(), "Could not parse attribute ID as a u64") + .to_compile_error(); + } + }; + + attrs.push(quote! { + static #name_with_attr: kernel::configfs::Attribute<#id, #data_ty, #data_ty> = + // SAFETY: We are expanding `configfs_attrs`. + unsafe { + kernel::configfs::Attribute::new(kernel::c_str!(::core::stringify!(#name))) + }; + + // SAFETY: By design of this macro, the name of the variable we + // invoke the `add` method on below, is not visible outside of + // the macro expansion. The macro does not operate concurrently + // on this variable, and thus we have exclusive access to the + // variable. + unsafe { #data_attr_ident.add::<#attr_idx, #id, _>(&#name_with_attr) } + }); + } + + let has_child_code = if let Some(child) = cfs_attrs.child { + quote! { new_with_child_ctor::<#n, #child>} + } else { + quote! { new::<#n> } + }; + + let data_type = quote! { + { + static #data_tp_ident: + kernel::configfs::ItemType<#container_ty, #data_ty> = + kernel::configfs::ItemType::<#container_ty, #data_ty>::#has_child_code( + &THIS_MODULE, &#data_attr_ident + ); + &#data_tp_ident + } + }; + + quote! { + { + #attr_list + #(#attrs)* + #data_type + } + } +} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 2cfd59e0f9e7c..745ba83c828b9 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -15,6 +15,8 @@ #![cfg_attr(not(CONFIG_RUSTC_HAS_SPAN_FILE), feature(proc_macro_span))] mod concat_idents; +#[cfg(CONFIG_CONFIGFS_FS)] +mod configfs_attrs; mod export; mod fmt; mod helpers; @@ -489,3 +491,86 @@ pub fn kunit_tests(attr: TokenStream, input: TokenStream) -> TokenStream { .unwrap_or_else(|e| e.into_compile_error()) .into() } + +/// Define a list of configfs attributes statically. +/// +/// # Examples +/// +/// ```ignore +/// let item_type = configfs_attrs! { +/// container: configfs::Subsystem, +/// data: Configuration, +/// child: Child, +/// attributes: [ +/// message: 0, +/// bar: 1, +/// ], +/// }; +///``` +/// +/// Expands the following output: +/// let item_type = { +/// static CONFIGURATION_ATTR_LIST: kernel::configfs::AttributeList< +/// 3usize, +/// Configuration, +/// > = unsafe { kernel::configfs::AttributeList::new() }; +/// static MESSAGE_ATTR: kernel::configfs::Attribute< +/// 0u64, +/// Configuration, +/// Configuration, +/// > = unsafe { +/// kernel::configfs::Attribute::new({ +/// const S: &str = "message\u{0}"; +/// const C: &kernel::str::CStr = match kernel::str::CStr::from_bytes_with_nul( +/// S.as_bytes(), +/// ) { +/// Ok(v) => v, +/// Err(_) => { +/// ::core::panicking::panic_fmt( +/// format_args!("string contains interior NUL"), +/// ); +/// } +/// }; +/// C +/// }) +/// }; +/// unsafe { CONFIGURATION_ATTR_LIST.add::<0usize, 0u64, _>(&MESSAGE_ATTR) } +/// static BAR_ATTR: kernel::configfs::Attribute< +/// 1u64, +/// Configuration, +/// Configuration, +/// > = unsafe { +/// kernel::configfs::Attribute::new({ +/// const S: &str = "bar\u{0}"; +/// const C: &kernel::str::CStr = match kernel::str::CStr::from_bytes_with_nul( +/// S.as_bytes(), +/// ) { +/// Ok(v) => v, +/// Err(_) => { +/// ::core::panicking::panic_fmt( +/// format_args!("string contains interior NUL"), +/// ); +/// } +/// }; +/// C +/// }) +/// }; +/// unsafe { CONFIGURATION_ATTR_LIST.add::<1usize, 1u64, _>(&BAR_ATTR) } +/// { +/// static CONFIGURATION_TPE: kernel::configfs::ItemType< +/// Subsystem, +/// Configuration, +/// > = kernel::configfs::ItemType::< +/// Subsystem, +/// Configuration, +/// >::new_with_child_ctor::<3usize, Child>(&THIS_MODULE, &CONFIGURATION_ATTR_LIST); +/// &CONFIGURATION_TPE +/// } +/// }; +/// +#[cfg(CONFIG_CONFIGFS_FS)] +#[proc_macro] +pub fn configfs_attrs(input: TokenStream) -> TokenStream { + configfs_attrs::configfs_attrs(parse_macro_input!(input as configfs_attrs::ConfigfsAttrs)) + .into() +} diff --git a/samples/rust/rust_configfs.rs b/samples/rust/rust_configfs.rs index a1bd9db6010da..876462f7789d1 100644 --- a/samples/rust/rust_configfs.rs +++ b/samples/rust/rust_configfs.rs @@ -4,7 +4,7 @@ use kernel::alloc::flags; use kernel::configfs; -use kernel::configfs::configfs_attrs; +use kernel::macros::configfs_attrs; use kernel::new_mutex; use kernel::page::PAGE_SIZE; use kernel::prelude::*; --- base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731 change-id: 20260417-configfs-syn-191e07130027 Best regards, -- Malte Wechter