Re: [PATCH v7 21/26] rust: alloc: implement `contains` for `Flags`

Gary Guo
2024-09-28T19:31:29Z

On Thu, 12 Sep 2024 00:52:57 +0200
Danilo Krummrich <dakr@kernel.org> wrote:

> Provide a simple helper function to check whether given flags do
> contain one or multiple other flags.
>
> This is used by a subsequent patch implementing the Cmalloc `Allocator`
> to check for __GFP_ZERO.
>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Reviewed-by: Benno Lossin <benno.lossin@proton.me>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

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

> ---
> rust/kernel/alloc.rs | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
> index aabdf80e4f7b..caa0b9dfac87 100644
> --- a/rust/kernel/alloc.rs
> +++ b/rust/kernel/alloc.rs
> @@ -34,7 +34,7 @@
> /// They can be combined with the operators `|`, `&`, and `!`.
> ///
> /// Values can be used from the [`flags`] module.
> -#[derive(Clone, Copy)]
> +#[derive(Clone, Copy, PartialEq)]
> pub struct Flags(u32);
>
> impl Flags {
> @@ -42,6 +42,11 @@ impl Flags {
> pub(crate) fn as_raw(self) -> u32 {
> self.0
> }
> +
> + /// Check whether `flags` is contained in `self`.
> + pub fn contains(self, flags: Flags) -> bool {
> + (self & flags) == flags
> + }
> }
>
> impl core::ops::BitOr for Flags {