[v5,21/26] rust: alloc: implement `contains` for `Flags`

Commit Message

Danilo Krummrich Aug. 12, 2024, 6:23 p.m. UTC

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 <[e-mail]>
Signed-off-by: Danilo Krummrich <[e-mail]>
---
 rust/kernel/alloc.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Patch

diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
index 820ef6072e02..be2bd0f1e74a 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 {