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* [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()`
@ 2024-03-09 15:53 Benno Lossin
  2024-03-09 15:54 ` [PATCH v3 2/3] rust: macros: allow generic parameter default values in `#[pin_data]` Benno Lossin
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Benno Lossin @ 2024-03-09 15:53 UTC (permalink / raw)
  To: Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho, Boqun Feng,
	Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
	Alice Ryhl, Martin Rodriguez Reboredo, Asahi Lina
  Cc: rust-for-linux, linux-kernel

The generic parameters on a type definition can specify default values.
Currently `parse_generics()` cannot handle this though. For example when
parsing the following generics:

    <T: Clone, const N: usize = 0>

The `impl_generics` will be set to `T: Clone, const N: usize = 0` and
`ty_generics` will be set to `T, N`. Now using the `impl_generics` on an
impl block:

    impl<$($impl_generics)*> Foo {}

will result in invalid Rust code, because default values are only
available on type definitions.

Therefore add parsing support for generic parameter default values using
a new kind of generics called `decl_generics` and change the old
behavior of `impl_generics` to not contain the generic parameter default
values.

Now `Generics` has three fields:
- `impl_generics`: the generics with bounds
  (e.g. `T: Clone, const N: usize`)
- `decl_generics`: the generics with bounds and default values
  (e.g. `T: Clone, const N: usize = 0`)
- `ty_generics`:  contains the generics without bounds and without
  default values (e.g. `T, N`)

`impl_generics` is designed to be used on `impl<$impl_generics>`,
`decl_generics` for the type definition, so `struct Foo<$decl_generics>`
and `ty_generics` whenever you use the type, so `Foo<$ty_generics>`.

Here is an example that uses all three different types of generics:

    let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input);
    quote! {
        struct Foo<$($decl_generics)*> {
            // ...
        }

        impl<$impl_generics> Foo<$ty_generics> {
            fn foo() {
                // ...
            }
        }
    }

The next commit contains a fix to the `#[pin_data]` macro making it
compatible with generic parameter default values by relying on this new
behavior.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
---
v2 -> v3:
- addressed Gary's nits
- add #[allow(dead_code)] to remove warning
- rebase onto rust-next

v1 -> v2:
- improve documentation and commit message explanation
- add motivation to commit message


v1: https://lore.kernel.org/rust-for-linux/20231125125024.1235933-1-benno.lossin@proton.me/
v2: https://lore.kernel.org/rust-for-linux/20231213220447.3613500-1-benno.lossin@proton.me/

 rust/macros/helpers.rs  | 123 ++++++++++++++++++++++++++++++----------
 rust/macros/pin_data.rs |   1 +
 rust/macros/zeroable.rs |   1 +
 3 files changed, 95 insertions(+), 30 deletions(-)

diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
index afb0f2e3a36a..2497d6519f2f 100644
--- a/rust/macros/helpers.rs
+++ b/rust/macros/helpers.rs
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{token_stream, Group, Punct, Spacing, TokenStream, TokenTree};
+use proc_macro::{token_stream, Group, TokenStream, TokenTree};
 
 pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
     if let Some(TokenTree::Ident(ident)) = it.next() {
@@ -70,8 +70,41 @@ pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
     }
 }
 
+/// Parsed generics.
+///
+/// See the field documentation for an explanation what each of the fields represents.
+///
+/// # Examples
+///
+/// ```rust,ignore
+/// # let input = todo!();
+/// let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input);
+/// quote! {
+///     struct Foo<$($decl_generics)*> {
+///         // ...
+///     }
+///
+///     impl<$impl_generics> Foo<$ty_generics> {
+///         fn foo() {
+///             // ...
+///         }
+///     }
+/// }
+/// ```
 pub(crate) struct Generics {
+    /// The generics with bounds and default values (e.g. `T: Clone, const N: usize = 0`).
+    ///
+    /// Use this on type definitions e.g. `struct Foo<$decl_generics> ...` (or `union`/`enum`).
+    #[allow(dead_code)]
+    pub(crate) decl_generics: Vec<TokenTree>,
+    /// The generics with bounds (e.g. `T: Clone, const N: usize`).
+    ///
+    /// Use this on `impl` blocks e.g. `impl<$impl_generics> Trait for ...`.
     pub(crate) impl_generics: Vec<TokenTree>,
+    /// The generics without bounds and without default values (e.g. `T, N`).
+    ///
+    /// Use this when you use the type that is declared with these generics e.g.
+    /// `Foo<$ty_generics>`.
     pub(crate) ty_generics: Vec<TokenTree>,
 }
 
@@ -79,6 +112,8 @@ pub(crate) struct Generics {
 ///
 /// The generics are not present in the rest, but a where clause might remain.
 pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) {
+    // The generics with bounds and default values.
+    let mut decl_generics = vec![];
     // `impl_generics`, the declared generics with their bounds.
     let mut impl_generics = vec![];
     // Only the names of the generics, without any bounds.
@@ -90,10 +125,17 @@ pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) {
     let mut toks = input.into_iter();
     // If we are at the beginning of a generic parameter.
     let mut at_start = true;
-    for tt in &mut toks {
+    let mut skip_until_comma = false;
+    while let Some(tt) = toks.next() {
+        if nesting == 1 && matches!(&tt, TokenTree::Punct(p) if p.as_char() == '>') {
+            // Found the end of the generics.
+            break;
+        } else if nesting >= 1 {
+            decl_generics.push(tt.clone());
+        }
         match tt.clone() {
             TokenTree::Punct(p) if p.as_char() == '<' => {
-                if nesting >= 1 {
+                if nesting >= 1 && !skip_until_comma {
                     // This is inside of the generics and part of some bound.
                     impl_generics.push(tt);
                 }
@@ -105,49 +147,70 @@ pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) {
                     break;
                 } else {
                     nesting -= 1;
-                    if nesting >= 1 {
+                    if nesting >= 1 && !skip_until_comma {
                         // We are still inside of the generics and part of some bound.
                         impl_generics.push(tt);
                     }
-                    if nesting == 0 {
-                        break;
-                    }
                 }
             }
-            tt => {
+            TokenTree::Punct(p) if skip_until_comma && p.as_char() == ',' => {
                 if nesting == 1 {
-                    // Here depending on the token, it might be a generic variable name.
-                    match &tt {
-                        // Ignore const.
-                        TokenTree::Ident(i) if i.to_string() == "const" => {}
-                        TokenTree::Ident(_) if at_start => {
-                            ty_generics.push(tt.clone());
-                            // We also already push the `,` token, this makes it easier to append
-                            // generics.
-                            ty_generics.push(TokenTree::Punct(Punct::new(',', Spacing::Alone)));
-                            at_start = false;
-                        }
-                        TokenTree::Punct(p) if p.as_char() == ',' => at_start = true,
-                        // Lifetimes begin with `'`.
-                        TokenTree::Punct(p) if p.as_char() == '\'' && at_start => {
-                            ty_generics.push(tt.clone());
-                        }
-                        _ => {}
-                    }
-                }
-                if nesting >= 1 {
+                    impl_generics.push(tt.clone());
                     impl_generics.push(tt);
-                } else if nesting == 0 {
+                    skip_until_comma = false;
+                }
+            }
+            _ if !skip_until_comma => {
+                match nesting {
                     // If we haven't entered the generics yet, we still want to keep these tokens.
-                    rest.push(tt);
+                    0 => rest.push(tt),
+                    1 => {
+                        // Here depending on the token, it might be a generic variable name.
+                        match tt.clone() {
+                            TokenTree::Ident(i) if at_start && i.to_string() == "const" => {
+                                let Some(name) = toks.next() else {
+                                    // Parsing error.
+                                    break;
+                                };
+                                impl_generics.push(tt);
+                                impl_generics.push(name.clone());
+                                ty_generics.push(name.clone());
+                                decl_generics.push(name);
+                                at_start = false;
+                            }
+                            TokenTree::Ident(_) if at_start => {
+                                impl_generics.push(tt.clone());
+                                ty_generics.push(tt);
+                                at_start = false;
+                            }
+                            TokenTree::Punct(p) if p.as_char() == ',' => {
+                                impl_generics.push(tt.clone());
+                                ty_generics.push(tt);
+                                at_start = true;
+                            }
+                            // Lifetimes begin with `'`.
+                            TokenTree::Punct(p) if p.as_char() == '\'' && at_start => {
+                                impl_generics.push(tt.clone());
+                                ty_generics.push(tt);
+                            }
+                            // Generics can have default values, we skip these.
+                            TokenTree::Punct(p) if p.as_char() == '=' => {
+                                skip_until_comma = true;
+                            }
+                            _ => impl_generics.push(tt),
+                        }
+                    }
+                    _ => impl_generics.push(tt),
                 }
             }
+            _ => {}
         }
     }
     rest.extend(toks);
     (
         Generics {
             impl_generics,
+            decl_generics,
             ty_generics,
         },
         rest,
diff --git a/rust/macros/pin_data.rs b/rust/macros/pin_data.rs
index 6d58cfda9872..022e68e9720d 100644
--- a/rust/macros/pin_data.rs
+++ b/rust/macros/pin_data.rs
@@ -10,6 +10,7 @@ pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
     let (
         Generics {
             impl_generics,
+            decl_generics: _,
             ty_generics,
         },
         rest,
diff --git a/rust/macros/zeroable.rs b/rust/macros/zeroable.rs
index 0d605c46ab3b..cfee2cec18d5 100644
--- a/rust/macros/zeroable.rs
+++ b/rust/macros/zeroable.rs
@@ -7,6 +7,7 @@ pub(crate) fn derive(input: TokenStream) -> TokenStream {
     let (
         Generics {
             impl_generics,
+            decl_generics: _,
             ty_generics,
         },
         mut rest,

base-commit: 768409cff6cc89fe1194da880537a09857b6e4db
-- 
2.42.0



^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH v3 2/3] rust: macros: allow generic parameter default values in `#[pin_data]`
  2024-03-09 15:53 [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Benno Lossin
@ 2024-03-09 15:54 ` Benno Lossin
  2024-03-09 15:54 ` [PATCH v3 3/3] rust: workqueue: add `#[pin_data]` to `Work` Benno Lossin
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Benno Lossin @ 2024-03-09 15:54 UTC (permalink / raw)
  To: Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho, Boqun Feng,
	Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
	Alice Ryhl, Martin Rodriguez Reboredo, Asahi Lina
  Cc: rust-for-linux, linux-kernel

Add support for generic parameters defaults in `#[pin_data]` by using
the newly introduced `decl_generics` instead of the `impl_generics`.

Before this would not compile:

    #[pin_data]
    struct Foo<const N: usize = 0> {
        // ...
    }

because it would be expanded to this:

    struct Foo<const N: usize = 0> {
        // ...
    }

    const _: () = {
        struct __ThePinData<const N: usize = 0> {
            __phantom: ::core::marker::PhantomData<fn(Foo<N>) -> Foo<N>>,
        }
        impl<const N: usize = 0> ::core::clone::Clone for __ThePinData<N> {
            fn clone(&self) -> Self {
                *self
            }
        }

        // [...] rest of expansion omitted
    };

The problem is with the `impl<const N: usize = 0>`, since that is
invalid Rust syntax. It should not mention the default value at all,
since default values only make sense on type definitions.

The new `impl_generics` do not contain the default values, thus
generating correct Rust code.

This is used by the next commit that puts `#[pin_data]` on
`kernel::workqueue::Work`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
---
v2 -> v3:
- remove #[allow(dead_code)] since that part of the code is now used

v1 -> v2:
- clarify the change in the commit message
- add motivation to the commit message

 rust/kernel/init/macros.rs | 19 ++++++++++++++++++-
 rust/macros/helpers.rs     |  1 -
 rust/macros/pin_data.rs    |  3 ++-
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs
index cb6e61b6c50b..624e9108e3b4 100644
--- a/rust/kernel/init/macros.rs
+++ b/rust/kernel/init/macros.rs
@@ -538,6 +538,7 @@ macro_rules! __pin_data {
         ),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @body({ $($fields:tt)* }),
     ) => {
         // We now use token munching to iterate through all of the fields. While doing this we
@@ -560,6 +561,9 @@ macro_rules! __pin_data {
             @impl_generics($($impl_generics)*),
             // The 'ty generics', the generics that will need to be specified on the impl blocks.
             @ty_generics($($ty_generics)*),
+            // The 'decl generics', the generics that need to be specified on the struct
+            // definition.
+            @decl_generics($($decl_generics)*),
             // The where clause of any impl block and the declaration.
             @where($($($whr)*)?),
             // The remaining fields tokens that need to be processed.
@@ -585,6 +589,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We found a PhantomPinned field, this should generally be pinned!
         @fields_munch($field:ident : $($($(::)?core::)?marker::)?PhantomPinned, $($rest:tt)*),
@@ -607,6 +612,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($($rest)*),
             @pinned($($pinned)* $($accum)* $field: ::core::marker::PhantomPinned,),
@@ -623,6 +629,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We reached the field declaration.
         @fields_munch($field:ident : $type:ty, $($rest:tt)*),
@@ -640,6 +647,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($($rest)*),
             @pinned($($pinned)* $($accum)* $field: $type,),
@@ -656,6 +664,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We reached the field declaration.
         @fields_munch($field:ident : $type:ty, $($rest:tt)*),
@@ -673,6 +682,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($($rest)*),
             @pinned($($pinned)*),
@@ -689,6 +699,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We found the `#[pin]` attr.
         @fields_munch(#[pin] $($rest:tt)*),
@@ -705,6 +716,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($($rest)*),
             // We do not include `#[pin]` in the list of attributes, since it is not actually an
@@ -724,6 +736,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We reached the field declaration with visibility, for simplicity we only munch the
         // visibility and put it into `$accum`.
@@ -741,6 +754,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($field $($rest)*),
             @pinned($($pinned)*),
@@ -757,6 +771,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // Some other attribute, just put it into `$accum`.
         @fields_munch(#[$($attr:tt)*] $($rest:tt)*),
@@ -773,6 +788,7 @@ macro_rules! __pin_data {
             @name($name),
             @impl_generics($($impl_generics)*),
             @ty_generics($($ty_generics)*),
+            @decl_generics($($decl_generics)*),
             @where($($whr)*),
             @fields_munch($($rest)*),
             @pinned($($pinned)*),
@@ -789,6 +805,7 @@ macro_rules! __pin_data {
         @name($name:ident),
         @impl_generics($($impl_generics:tt)*),
         @ty_generics($($ty_generics:tt)*),
+        @decl_generics($($decl_generics:tt)*),
         @where($($whr:tt)*),
         // We reached the end of the fields, plus an optional additional comma, since we added one
         // before and the user is also allowed to put a trailing comma.
@@ -802,7 +819,7 @@ macro_rules! __pin_data {
     ) => {
         // Declare the struct with all fields in the correct order.
         $($struct_attrs)*
-        $vis struct $name <$($impl_generics)*>
+        $vis struct $name <$($decl_generics)*>
         where $($whr)*
         {
             $($fields)*
diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
index 2497d6519f2f..563dcd2b7ace 100644
--- a/rust/macros/helpers.rs
+++ b/rust/macros/helpers.rs
@@ -95,7 +95,6 @@ pub(crate) struct Generics {
     /// The generics with bounds and default values (e.g. `T: Clone, const N: usize = 0`).
     ///
     /// Use this on type definitions e.g. `struct Foo<$decl_generics> ...` (or `union`/`enum`).
-    #[allow(dead_code)]
     pub(crate) decl_generics: Vec<TokenTree>,
     /// The generics with bounds (e.g. `T: Clone, const N: usize`).
     ///
diff --git a/rust/macros/pin_data.rs b/rust/macros/pin_data.rs
index 022e68e9720d..1d4a3547c684 100644
--- a/rust/macros/pin_data.rs
+++ b/rust/macros/pin_data.rs
@@ -10,7 +10,7 @@ pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
     let (
         Generics {
             impl_generics,
-            decl_generics: _,
+            decl_generics,
             ty_generics,
         },
         rest,
@@ -77,6 +77,7 @@ pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
         @sig(#(#rest)*),
         @impl_generics(#(#impl_generics)*),
         @ty_generics(#(#ty_generics)*),
+        @decl_generics(#(#decl_generics)*),
         @body(#last),
     });
     quoted.extend(errs);
-- 
2.42.0



^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH v3 3/3] rust: workqueue: add `#[pin_data]` to `Work`
  2024-03-09 15:53 [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Benno Lossin
  2024-03-09 15:54 ` [PATCH v3 2/3] rust: macros: allow generic parameter default values in `#[pin_data]` Benno Lossin
@ 2024-03-09 15:54 ` Benno Lossin
  2024-03-11  9:06 ` [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Alice Ryhl
  2024-04-07 20:15 ` Miguel Ojeda
  3 siblings, 0 replies; 5+ messages in thread
From: Benno Lossin @ 2024-03-09 15:54 UTC (permalink / raw)
  To: Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho, Boqun Feng,
	Gary Guo, Björn Roy Baron, Benno Lossin, Andreas Hindborg,
	Alice Ryhl, Martin Rodriguez Reboredo, Valentin Obst
  Cc: Wedson Almeida Filho, rust-for-linux, linux-kernel

The previous two patches made it possible to add `#[pin_data]` on
structs with default generic parameter values.
This patch makes `Work` use `#[pin_data]` and removes an invocation of
`pin_init_from_closure`. This function is intended as a low level manual
escape hatch, so it is better to rely on the safe `pin_init!` macro.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
---
v2 -> v3:
no changes

v1 -> v2:
- improve commit message wording
- change `:` to `<-` in `pin_init!` invocation

 rust/kernel/workqueue.rs | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index 544f0c51f1b7..ab4d64fbdb78 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -342,8 +342,10 @@ pub trait WorkItem<const ID: u64 = 0> {
 /// This is a helper type used to associate a `work_struct` with the [`WorkItem`] that uses it.
 ///
 /// [`run`]: WorkItemPointer::run
+#[pin_data]
 #[repr(transparent)]
 pub struct Work<T: ?Sized, const ID: u64 = 0> {
+    #[pin]
     work: Opaque<bindings::work_struct>,
     _inner: PhantomData<T>,
 }
@@ -365,21 +367,22 @@ pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self
     where
         T: WorkItem<ID>,
     {
-        // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as the work
-        // item function.
-        unsafe {
-            kernel::init::pin_init_from_closure(move |slot| {
-                let slot = Self::raw_get(slot);
-                bindings::init_work_with_key(
-                    slot,
-                    Some(T::Pointer::run),
-                    false,
-                    name.as_char_ptr(),
-                    key.as_ptr(),
-                );
-                Ok(())
-            })
-        }
+        pin_init!(Self {
+            work <- Opaque::ffi_init(|slot| {
+                // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as
+                // the work item function.
+                unsafe {
+                    bindings::init_work_with_key(
+                        slot,
+                        Some(T::Pointer::run),
+                        false,
+                        name.as_char_ptr(),
+                        key.as_ptr(),
+                    )
+                }
+            }),
+            _inner: PhantomData,
+        })
     }
 
     /// Get a pointer to the inner `work_struct`.
-- 
2.42.0



^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()`
  2024-03-09 15:53 [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Benno Lossin
  2024-03-09 15:54 ` [PATCH v3 2/3] rust: macros: allow generic parameter default values in `#[pin_data]` Benno Lossin
  2024-03-09 15:54 ` [PATCH v3 3/3] rust: workqueue: add `#[pin_data]` to `Work` Benno Lossin
@ 2024-03-11  9:06 ` Alice Ryhl
  2024-04-07 20:15 ` Miguel Ojeda
  3 siblings, 0 replies; 5+ messages in thread
From: Alice Ryhl @ 2024-03-11  9:06 UTC (permalink / raw)
  To: Benno Lossin
  Cc: Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho, Boqun Feng,
	Gary Guo, Björn Roy Baron, Andreas Hindborg,
	Martin Rodriguez Reboredo, Asahi Lina, rust-for-linux,
	linux-kernel

On Sat, Mar 9, 2024 at 4:53 PM Benno Lossin <benno.lossin@proton.me> wrote:
>
> The generic parameters on a type definition can specify default values.
> Currently `parse_generics()` cannot handle this though. For example when
> parsing the following generics:
>
>     <T: Clone, const N: usize = 0>
>
> The `impl_generics` will be set to `T: Clone, const N: usize = 0` and
> `ty_generics` will be set to `T, N`. Now using the `impl_generics` on an
> impl block:
>
>     impl<$($impl_generics)*> Foo {}
>
> will result in invalid Rust code, because default values are only
> available on type definitions.
>
> Therefore add parsing support for generic parameter default values using
> a new kind of generics called `decl_generics` and change the old
> behavior of `impl_generics` to not contain the generic parameter default
> values.
>
> Now `Generics` has three fields:
> - `impl_generics`: the generics with bounds
>   (e.g. `T: Clone, const N: usize`)
> - `decl_generics`: the generics with bounds and default values
>   (e.g. `T: Clone, const N: usize = 0`)
> - `ty_generics`:  contains the generics without bounds and without
>   default values (e.g. `T, N`)
>
> `impl_generics` is designed to be used on `impl<$impl_generics>`,
> `decl_generics` for the type definition, so `struct Foo<$decl_generics>`
> and `ty_generics` whenever you use the type, so `Foo<$ty_generics>`.
>
> Here is an example that uses all three different types of generics:
>
>     let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input);
>     quote! {
>         struct Foo<$($decl_generics)*> {
>             // ...
>         }
>
>         impl<$impl_generics> Foo<$ty_generics> {
>             fn foo() {
>                 // ...
>             }
>         }
>     }
>
> The next commit contains a fix to the `#[pin_data]` macro making it
> compatible with generic parameter default values by relying on this new
> behavior.
>
> Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()`
  2024-03-09 15:53 [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Benno Lossin
                   ` (2 preceding siblings ...)
  2024-03-11  9:06 ` [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Alice Ryhl
@ 2024-04-07 20:15 ` Miguel Ojeda
  3 siblings, 0 replies; 5+ messages in thread
From: Miguel Ojeda @ 2024-04-07 20:15 UTC (permalink / raw)
  To: Benno Lossin
  Cc: Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho, Boqun Feng,
	Gary Guo, Björn Roy Baron, Andreas Hindborg, Alice Ryhl,
	Martin Rodriguez Reboredo, Asahi Lina, rust-for-linux,
	linux-kernel

On Sat, Mar 9, 2024 at 4:53 PM Benno Lossin <benno.lossin@proton.me> wrote:
>
> The generic parameters on a type definition can specify default values.
> Currently `parse_generics()` cannot handle this though. For example when
> parsing the following generics:
>
>     <T: Clone, const N: usize = 0>
>
> The `impl_generics` will be set to `T: Clone, const N: usize = 0` and
> `ty_generics` will be set to `T, N`. Now using the `impl_generics` on an
> impl block:
>
>     impl<$($impl_generics)*> Foo {}
>
> will result in invalid Rust code, because default values are only
> available on type definitions.
>
> Therefore add parsing support for generic parameter default values using
> a new kind of generics called `decl_generics` and change the old
> behavior of `impl_generics` to not contain the generic parameter default
> values.
>
> Now `Generics` has three fields:
> - `impl_generics`: the generics with bounds
>   (e.g. `T: Clone, const N: usize`)
> - `decl_generics`: the generics with bounds and default values
>   (e.g. `T: Clone, const N: usize = 0`)
> - `ty_generics`:  contains the generics without bounds and without
>   default values (e.g. `T, N`)
>
> `impl_generics` is designed to be used on `impl<$impl_generics>`,
> `decl_generics` for the type definition, so `struct Foo<$decl_generics>`
> and `ty_generics` whenever you use the type, so `Foo<$ty_generics>`.
>
> Here is an example that uses all three different types of generics:
>
>     let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input);
>     quote! {
>         struct Foo<$($decl_generics)*> {
>             // ...
>         }
>
>         impl<$impl_generics> Foo<$ty_generics> {
>             fn foo() {
>                 // ...
>             }
>         }
>     }
>
> The next commit contains a fix to the `#[pin_data]` macro making it
> compatible with generic parameter default values by relying on this new
> behavior.
>
> Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Applied series to `rust-next` -- thanks everyone!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2024-04-07 20:15 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-03-09 15:53 [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Benno Lossin
2024-03-09 15:54 ` [PATCH v3 2/3] rust: macros: allow generic parameter default values in `#[pin_data]` Benno Lossin
2024-03-09 15:54 ` [PATCH v3 3/3] rust: workqueue: add `#[pin_data]` to `Work` Benno Lossin
2024-03-11  9:06 ` [PATCH v3 1/3] rust: macros: add `decl_generics` to `parse_generics()` Alice Ryhl
2024-04-07 20:15 ` Miguel Ojeda

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