From: Tamir Duberstein Date: Wed, 9 Jul 2025 19:31:15 +0000 (-0400) Subject: rust: list: add `impl_list_item!` examples X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=5d840b4c4935cd5100be97b6df565b4b159970a5;p=users%2Fjedix%2Flinux-maple.git rust: list: add `impl_list_item!` examples There's a comprehensive example in `rust/kernel/list.rs` but it doesn't exercise the `using ListLinksSelfPtr` variant nor the generic cases. Add that here. Generalize `impl_has_list_links_self_ptr` to handle nested fields in the same manner as `impl_has_list_links`. Tested-by: Alice Ryhl Reviewed-by: Alice Ryhl Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20250709-list-no-offset-v4-5-a429e75840a9@gmail.com [ Fixed Rust < 1.82 build by enabling the `offset_of_nested` feature. - Miguel ] Signed-off-by: Miguel Ojeda --- diff --git a/rust/kernel/list/impl_list_item_mod.rs b/rust/kernel/list/impl_list_item_mod.rs index 6717b614e896..374b3dd812d0 100644 --- a/rust/kernel/list/impl_list_item_mod.rs +++ b/rust/kernel/list/impl_list_item_mod.rs @@ -82,20 +82,20 @@ macro_rules! impl_has_list_links_self_ptr { ($(impl$({$($generics:tt)*})? HasSelfPtr<$item_type:ty $(, $id:tt)?> for $self:ty - { self.$field:ident } + { self$(.$field:ident)* } )*) => {$( // SAFETY: The implementation of `raw_get_list_links` only compiles if the field has the // right type. unsafe impl$(<$($generics)*>)? $crate::list::HasSelfPtr<$item_type $(, $id)?> for $self {} unsafe impl$(<$($generics)*>)? $crate::list::HasListLinks$(<$id>)? for $self { - const OFFSET: usize = ::core::mem::offset_of!(Self, $field) as usize; + const OFFSET: usize = ::core::mem::offset_of!(Self, $($field).*) as usize; #[inline] unsafe fn raw_get_list_links(ptr: *mut Self) -> *mut $crate::list::ListLinks$(<$id>)? { // SAFETY: The caller promises that the pointer is not dangling. let ptr: *mut $crate::list::ListLinksSelfPtr<$item_type $(, $id)?> = - unsafe { ::core::ptr::addr_of_mut!((*ptr).$field) }; + unsafe { ::core::ptr::addr_of_mut!((*ptr)$(.$field)*) }; ptr.cast() } } @@ -109,6 +109,96 @@ pub use impl_has_list_links_self_ptr; /// implement that trait. /// /// [`ListItem`]: crate::list::ListItem +/// +/// # Examples +/// +/// ``` +/// #[pin_data] +/// struct SimpleListItem { +/// value: u32, +/// #[pin] +/// links: kernel::list::ListLinks, +/// } +/// +/// kernel::list::impl_has_list_links! { +/// impl HasListLinks<0> for SimpleListItem { self.links } +/// } +/// +/// kernel::list::impl_list_arc_safe! { +/// impl ListArcSafe<0> for SimpleListItem { untracked; } +/// } +/// +/// kernel::list::impl_list_item! { +/// impl ListItem<0> for SimpleListItem { using ListLinks; } +/// } +/// +/// struct ListLinksHolder { +/// inner: kernel::list::ListLinks, +/// } +/// +/// #[pin_data] +/// struct ComplexListItem { +/// value: Result, +/// #[pin] +/// links: ListLinksHolder, +/// } +/// +/// kernel::list::impl_has_list_links! { +/// impl{T, U} HasListLinks<0> for ComplexListItem { self.links.inner } +/// } +/// +/// kernel::list::impl_list_arc_safe! { +/// impl{T, U} ListArcSafe<0> for ComplexListItem { untracked; } +/// } +/// +/// kernel::list::impl_list_item! { +/// impl{T, U} ListItem<0> for ComplexListItem { using ListLinks; } +/// } +/// ``` +/// +/// ``` +/// #[pin_data] +/// struct SimpleListItem { +/// value: u32, +/// #[pin] +/// links: kernel::list::ListLinksSelfPtr, +/// } +/// +/// kernel::list::impl_list_arc_safe! { +/// impl ListArcSafe<0> for SimpleListItem { untracked; } +/// } +/// +/// kernel::list::impl_has_list_links_self_ptr! { +/// impl HasSelfPtr for SimpleListItem { self.links } +/// } +/// +/// kernel::list::impl_list_item! { +/// impl ListItem<0> for SimpleListItem { using ListLinksSelfPtr; } +/// } +/// +/// struct ListLinksSelfPtrHolder { +/// inner: kernel::list::ListLinksSelfPtr>, +/// } +/// +/// #[pin_data] +/// struct ComplexListItem { +/// value: Result, +/// #[pin] +/// links: ListLinksSelfPtrHolder, +/// } +/// +/// kernel::list::impl_list_arc_safe! { +/// impl{T, U} ListArcSafe<0> for ComplexListItem { untracked; } +/// } +/// +/// kernel::list::impl_has_list_links_self_ptr! { +/// impl{T, U} HasSelfPtr> for ComplexListItem { self.links.inner } +/// } +/// +/// kernel::list::impl_list_item! { +/// impl{T, U} ListItem<0> for ComplexListItem { using ListLinksSelfPtr; } +/// } +/// ``` #[macro_export] macro_rules! impl_list_item { ( diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a6461ea411f7..79c40af6f399 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -309,13 +309,14 @@ $(obj)/%.lst: $(obj)/%.c FORCE # The features in this list are the ones allowed for non-`rust/` code. # # - Stable since Rust 1.81.0: `feature(lint_reasons)`. -# - Stable since Rust 1.82.0: `feature(asm_const)`, `feature(raw_ref_op)`. +# - Stable since Rust 1.82.0: `feature(asm_const)`, +# `feature(offset_of_nested)`, `feature(raw_ref_op)`. # - Stable since Rust 1.87.0: `feature(asm_goto)`. # - Expected to become stable: `feature(arbitrary_self_types)`. # # Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on # the unstable features in use. -rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,raw_ref_op +rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,offset_of_nested,raw_ref_op # `--out-dir` is required to avoid temporaries being created by `rustc` in the # current working directory, which may be not accessible in the out-of-tree