diff mbox series

[RFC,01/11] rust: types: Add Opaque::zeroed()

Message ID 20230714-classless_lockdep-v1-1-229b9671ce31@asahilina.net
State New
Headers
Series rust: Implicit lock class creation & Arc Lockdep integration |

Commit Message

Asahi Lina July 14, 2023, 9:13 a.m. UTC 
  Opaque types are internally MaybeUninit, so it's safe to actually
zero-initialize them as long as we don't claim they are initialized.
This is useful for many FFI types that are expected to be zero-inited by
the user.

Signed-off-by: Asahi Lina <lina@asahilina.net>
---
 rust/kernel/types.rs | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Alice Ryhl July 14, 2023, 10:15 a.m. UTC | #1 
Asahi Lina <lina@asahilina.net> writes:
> Opaque types are internally MaybeUninit, so it's safe to actually
> zero-initialize them as long as we don't claim they are initialized.
> This is useful for many FFI types that are expected to be zero-inited by
> the user.
> 
> Signed-off-by: Asahi Lina <lina@asahilina.net>

LGTM. This is useful on its own.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Gary Guo July 15, 2023, 2:27 p.m. UTC | #2 
On Fri, 14 Jul 2023 18:13:53 +0900
Asahi Lina <lina@asahilina.net> wrote:

> Opaque types are internally MaybeUninit, so it's safe to actually
> zero-initialize them as long as we don't claim they are initialized.
> This is useful for many FFI types that are expected to be zero-inited by
> the user.
> 
> Signed-off-by: Asahi Lina <lina@asahilina.net>

Reviewed-by: Gary Guo <gary@garyguo.net>

I agree with Alice that this patch can accepted on its own.

> ---
>  rust/kernel/types.rs | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
> index 1e5380b16ed5..185d3493857e 100644
> --- a/rust/kernel/types.rs
> +++ b/rust/kernel/types.rs
> @@ -237,6 +237,11 @@ pub const fn uninit() -> Self {
>          Self(MaybeUninit::uninit())
>      }
>  
> +    /// Creates a zeroed value.
> +    pub fn zeroed() -> Self {
> +        Self(MaybeUninit::zeroed())
> +    }
> +
>      /// Creates a pin-initializer from the given initializer closure.
>      ///
>      /// The returned initializer calls the given closure with the pointer to the inner `T` of this
>
diff mbox series

Patch

diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 1e5380b16ed5..185d3493857e 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -237,6 +237,11 @@  pub const fn uninit() -> Self {
         Self(MaybeUninit::uninit())
     }
 
+    /// Creates a zeroed value.
+    pub fn zeroed() -> Self {
+        Self(MaybeUninit::zeroed())
+    }
+
     /// Creates a pin-initializer from the given initializer closure.
     ///
     /// The returned initializer calls the given closure with the pointer to the inner `T` of this