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Fri, 12 Jun 2026 06:29:35 -0700 (PDT) Received: from [192.168.6.4] ([195.100.225.50]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490ea7c09bcsm68062065e9.2.2026.06.12.06.29.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2026 06:29:35 -0700 (PDT) From: Malte Wechter Date: Fri, 12 Jun 2026 15:29:32 +0200 Subject: [PATCH v3] rust: add procedural macro for declaring configfs attributes Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260612-configfs-syn-v3-1-3292fbc5cc32@gmail.com> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/13MSw6CMBSF4a2Yjq25vUALjtyHcQC1hZtIa1rTS Ah7t+DAx/Cc5P9mFk0gE9lxN7NgEkXyLo9iv2N6aF1vOF3zZggooRSKa+8s9TbyODkuGmFAiQI AFcvJPRhLz407X/IeKD58mDY9ifV9QxXCL5QEF1zqqquhbbSxeOrHlm4H7Ue2Qgk/sYTiL8Yc6 66qy7rRKEv1HS/L8gKLsYH/5QAAAA== X-Change-ID: 20260417-configfs-syn-191e07130027 To: Andreas Hindborg , Breno Leitao , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jens Axboe , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-block@vger.kernel.org, linux-modules@vger.kernel.org, Malte Wechter X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1781270973; l=29763; i=maltewechter@gmail.com; s=20260417; h=from:subject:message-id; bh=bOa8N89iqzZv+qy+x7doRXt2ZIo4tvB4UJEg+SbbbOs=; b=7gqQ7RGOmGeIf1k8TkAMsYT4OB5hkkDYGRzSlf3KegYoen0xvK1OZEQQhcLi/IJBPJ5P835Yy kb+pELj59ZEBASq0FCc1EsjcsZ9sPiJLMrXDfcb8G3IwZMRRtOHqS8F X-Developer-Key: i=maltewechter@gmail.com; a=ed25519; pk=07WplWXZnwyLTMZOHNCIGcpoEutcMXU/JDY6f9VtxSY= 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 --- Changes in v3: - Remove 'make_static_ident' function, make names for static variables simpler - Move 'parse_ordered_fields' macro from module.rs into helpers - Use 'parse_ordered_fields' macro for parsing instead of doing it ad-hoc - Link to v2: https://lore.kernel.org/r/20260603-configfs-syn-v2-1-cb58489c2647@gmail.com Changes in v2: - Add a try_parse helper function to macros/helpers.rs - Fix bug where 'child' configuration gets dropped if trailing comma is missing (sashiko) - Link to v1: https://lore.kernel.org/r/20260520-configfs-syn-v1-1-6c5b80a9cef2@gmail.com --- MAINTAINERS | 1 + drivers/block/rnull/configfs.rs | 2 +- rust/kernel/configfs.rs | 251 ---------------------------------------- rust/macros/configfs_attrs.rs | 135 +++++++++++++++++++++ rust/macros/helpers.rs | 139 ++++++++++++++++++++++ rust/macros/lib.rs | 85 ++++++++++++++ rust/macros/module.rs | 137 ---------------------- samples/rust/rust_configfs.rs | 2 +- 8 files changed, 362 insertions(+), 390 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 2fb1c75afd16..45f7a1ec93b4 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 7c2eb5c0b722..f28ec69d7984 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 2339c6467325..7a91e36677f5 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 000000000000..81037bc38188 --- /dev/null +++ b/rust/macros/configfs_attrs.rs @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 + +use quote::{ + format_ident, + quote, // +}; + +use syn::{ + bracketed, + ext::IdentExt, + parse::{ + Parse, + ParseStream, // + }, + punctuated::Punctuated, + spanned::Spanned, + Error, + Ident, + LitInt, + Token, + Type, // +}; + +use crate::helpers::parse_ordered_fields; + +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_attributes(stream: ParseStream<'_>) -> syn::Result> { + let attr_stream; + let _bracket = bracketed!(attr_stream in stream); + let attributes = Punctuated::<(Ident, LitInt), Token![,]>::parse_terminated_with( + &attr_stream, + parse_attribute_field, + )?; + Ok(attributes.into_iter().collect::>()) +} + +impl Parse for ConfigfsAttrs { + fn parse(input: ParseStream<'_>) -> syn::Result { + parse_ordered_fields!( + from input; + container [required] => (input.parse::())?, + data [required] => (input.parse::())?, + child => (input.parse::())?, + attributes [required] => parse_attributes(input)?, + ); + + Ok(ConfigfsAttrs { + container, + data, + child, + attributes, + }) + } +} + +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 = Ident::new("DATA_TPE", cfs_attrs.data.span()); + let data_attr_ident = Ident::new("DATA_ATTR_LIST", cfs_attrs.data.span()); + + 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 = format_ident!("{}_ATTR_{}", name.to_string().to_uppercase(), attr_idx); + + 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/helpers.rs b/rust/macros/helpers.rs index d18fbf4daa0a..df524749631a 100644 --- a/rust/macros/helpers.rs +++ b/rust/macros/helpers.rs @@ -58,3 +58,142 @@ pub(crate) fn file() -> String { pub(crate) fn gather_cfg_attrs(attr: &[Attribute]) -> impl Iterator + '_ { attr.iter().filter(|a| a.path().is_ident("cfg")) } + +/// Parse fields that are required to use a specific order. +/// +/// As fields must follow a specific order, we *could* just parse fields one by one by peeking. +/// However the error message generated when implementing that way is not very friendly. +/// +/// So instead we parse fields in an arbitrary order, but only enforce the ordering after parsing, +/// and if the wrong order is used, the proper order is communicated to the user with error message. +/// +/// Usage looks like this: +/// ```ignore +/// parse_ordered_fields! { +/// from input; +/// +/// // This will extract "foo: " into a variable named "foo". +/// // The variable will have type `Option<_>`. +/// foo => , +/// +/// // If you need the variable name to be different than the key name. +/// // This extracts "baz: " into a variable named "bar". +/// // You might want this if "baz" is a keyword. +/// baz as bar => , +/// +/// // You can mark a key as required, and the variable will no longer be `Option`. +/// // foobar will be of type `Expr` instead of `Option`. +/// foobar [required] => input.parse::()?, +/// } +/// ``` +macro_rules! parse_ordered_fields { + (@gen + [$input:expr] + [$([$name:ident; $key:ident; $parser:expr])*] + [$([$req_name:ident; $req_key:ident])*] + ) => { + $(let mut $name = None;)* + + const EXPECTED_KEYS: &[&str] = &[$(stringify!($key),)*]; + const REQUIRED_KEYS: &[&str] = &[$(stringify!($req_key),)*]; + + let span = $input.span(); + let mut seen_keys = Vec::new(); + + while !$input.is_empty() { + let key = $input.call(Ident::parse_any)?; + + if seen_keys.contains(&key) { + Err(Error::new_spanned( + &key, + format!(r#"duplicated key "{key}". Keys can only be specified once."#), + ))? + } + + $input.parse::()?; + + match &*key.to_string() { + $( + stringify!($key) => $name = Some($parser), + )* + _ => { + Err(Error::new_spanned( + &key, + format!(r#"unknown key "{key}". Valid keys are: {EXPECTED_KEYS:?}."#), + ))? + } + } + + $input.parse::()?; + seen_keys.push(key); + } + + for key in REQUIRED_KEYS { + if !seen_keys.iter().any(|e| e == key) { + Err(Error::new(span, format!(r#"missing required key "{key}""#)))? + } + } + + let mut ordered_keys: Vec<&str> = Vec::new(); + for key in EXPECTED_KEYS { + if seen_keys.iter().any(|e| e == key) { + ordered_keys.push(key); + } + } + + if seen_keys != ordered_keys { + Err(Error::new( + span, + format!(r#"keys are not ordered as expected. Order them like: {ordered_keys:?}."#), + ))? + } + + $(let $req_name = $req_name.expect("required field");)* + }; + + // Handle required fields. + (@gen + [$input:expr] [$($tok:tt)*] [$($req:tt)*] + $key:ident as $name:ident [required] => $parser:expr, + $($rest:tt)* + ) => { + parse_ordered_fields!( + @gen [$input] [$($tok)* [$name; $key; $parser]] [$($req)* [$name; $key]] $($rest)* + ) + }; + (@gen + [$input:expr] [$($tok:tt)*] [$($req:tt)*] + $name:ident [required] => $parser:expr, + $($rest:tt)* + ) => { + parse_ordered_fields!( + @gen [$input] [$($tok)* [$name; $name; $parser]] [$($req)* [$name; $name]] $($rest)* + ) + }; + + // Handle optional fields. + (@gen + [$input:expr] [$($tok:tt)*] [$($req:tt)*] + $key:ident as $name:ident => $parser:expr, + $($rest:tt)* + ) => { + parse_ordered_fields!( + @gen [$input] [$($tok)* [$name; $key; $parser]] [$($req)*] $($rest)* + ) + }; + (@gen + [$input:expr] [$($tok:tt)*] [$($req:tt)*] + $name:ident => $parser:expr, + $($rest:tt)* + ) => { + parse_ordered_fields!( + @gen [$input] [$($tok)* [$name; $name; $parser]] [$($req)*] $($rest)* + ) + }; + + (from $input:expr; $($tok:tt)*) => { + parse_ordered_fields!(@gen [$input] [] [] $($tok)*) + } +} + +pub(crate) use parse_ordered_fields; diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 2cfd59e0f9e7..be04d94d0bc5 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 DATA_ATTR_LIST: kernel::configfs::AttributeList< +/// 3usize, +/// Configuration, +/// > = unsafe { kernel::configfs::AttributeList::new() }; +/// static MESSAGE_ATTR_0: 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 { DATA_ATTR_LIST.add::<0usize, 0u64, _>(&MESSAGE_ATTR_0) } +/// static BAR_ATTR_1: 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 { DATA_ATTR_LIST.add::<1usize, 1u64, _>(&BAR_ATTR_1) } +/// { +/// static DATA_TPE: kernel::configfs::ItemType< +/// Subsystem, +/// Configuration, +/// > = kernel::configfs::ItemType::< +/// Subsystem, +/// Configuration, +/// >::new_with_child_ctor::<3usize, Child>(&THIS_MODULE, &DATA_ATTR_LIST); +/// &DATA_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/rust/macros/module.rs b/rust/macros/module.rs index 06c18e207508..7ff6ad09b1a2 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -196,143 +196,6 @@ fn param_ops_path(param_type: &str) -> Path { } } -/// Parse fields that are required to use a specific order. -/// -/// As fields must follow a specific order, we *could* just parse fields one by one by peeking. -/// However the error message generated when implementing that way is not very friendly. -/// -/// So instead we parse fields in an arbitrary order, but only enforce the ordering after parsing, -/// and if the wrong order is used, the proper order is communicated to the user with error message. -/// -/// Usage looks like this: -/// ```ignore -/// parse_ordered_fields! { -/// from input; -/// -/// // This will extract "foo: " into a variable named "foo". -/// // The variable will have type `Option<_>`. -/// foo => , -/// -/// // If you need the variable name to be different than the key name. -/// // This extracts "baz: " into a variable named "bar". -/// // You might want this if "baz" is a keyword. -/// baz as bar => , -/// -/// // You can mark a key as required, and the variable will no longer be `Option`. -/// // foobar will be of type `Expr` instead of `Option`. -/// foobar [required] => input.parse::()?, -/// } -/// ``` -macro_rules! parse_ordered_fields { - (@gen - [$input:expr] - [$([$name:ident; $key:ident; $parser:expr])*] - [$([$req_name:ident; $req_key:ident])*] - ) => { - $(let mut $name = None;)* - - const EXPECTED_KEYS: &[&str] = &[$(stringify!($key),)*]; - const REQUIRED_KEYS: &[&str] = &[$(stringify!($req_key),)*]; - - let span = $input.span(); - let mut seen_keys = Vec::new(); - - while !$input.is_empty() { - let key = $input.call(Ident::parse_any)?; - - if seen_keys.contains(&key) { - Err(Error::new_spanned( - &key, - format!(r#"duplicated key "{key}". Keys can only be specified once."#), - ))? - } - - $input.parse::()?; - - match &*key.to_string() { - $( - stringify!($key) => $name = Some($parser), - )* - _ => { - Err(Error::new_spanned( - &key, - format!(r#"unknown key "{key}". Valid keys are: {EXPECTED_KEYS:?}."#), - ))? - } - } - - $input.parse::()?; - seen_keys.push(key); - } - - for key in REQUIRED_KEYS { - if !seen_keys.iter().any(|e| e == key) { - Err(Error::new(span, format!(r#"missing required key "{key}""#)))? - } - } - - let mut ordered_keys: Vec<&str> = Vec::new(); - for key in EXPECTED_KEYS { - if seen_keys.iter().any(|e| e == key) { - ordered_keys.push(key); - } - } - - if seen_keys != ordered_keys { - Err(Error::new( - span, - format!(r#"keys are not ordered as expected. Order them like: {ordered_keys:?}."#), - ))? - } - - $(let $req_name = $req_name.expect("required field");)* - }; - - // Handle required fields. - (@gen - [$input:expr] [$($tok:tt)*] [$($req:tt)*] - $key:ident as $name:ident [required] => $parser:expr, - $($rest:tt)* - ) => { - parse_ordered_fields!( - @gen [$input] [$($tok)* [$name; $key; $parser]] [$($req)* [$name; $key]] $($rest)* - ) - }; - (@gen - [$input:expr] [$($tok:tt)*] [$($req:tt)*] - $name:ident [required] => $parser:expr, - $($rest:tt)* - ) => { - parse_ordered_fields!( - @gen [$input] [$($tok)* [$name; $name; $parser]] [$($req)* [$name; $name]] $($rest)* - ) - }; - - // Handle optional fields. - (@gen - [$input:expr] [$($tok:tt)*] [$($req:tt)*] - $key:ident as $name:ident => $parser:expr, - $($rest:tt)* - ) => { - parse_ordered_fields!( - @gen [$input] [$($tok)* [$name; $key; $parser]] [$($req)*] $($rest)* - ) - }; - (@gen - [$input:expr] [$($tok:tt)*] [$($req:tt)*] - $name:ident => $parser:expr, - $($rest:tt)* - ) => { - parse_ordered_fields!( - @gen [$input] [$($tok)* [$name; $name; $parser]] [$($req)*] $($rest)* - ) - }; - - (from $input:expr; $($tok:tt)*) => { - parse_ordered_fields!(@gen [$input] [] [] $($tok)*) - } -} - struct Parameter { name: Ident, ptype: Ident, diff --git a/samples/rust/rust_configfs.rs b/samples/rust/rust_configfs.rs index a1bd9db6010d..876462f7789d 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