diff options
Diffstat (limited to 'rust/kernel/sync/refcount.rs')
| -rw-r--r-- | rust/kernel/sync/refcount.rs | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/rust/kernel/sync/refcount.rs b/rust/kernel/sync/refcount.rs index cc1a80ae7ae9..19236a5bccde 100644 --- a/rust/kernel/sync/refcount.rs +++ b/rust/kernel/sync/refcount.rs @@ -5,6 +5,7 @@ //! C header: [`include/linux/refcount.h`](srctree/include/linux/refcount.h) use crate::build_assert; +use crate::sync::atomic::Atomic; use crate::types::Opaque; /// Atomic reference counter. @@ -34,6 +35,20 @@ impl Refcount { self.0.get() } + /// Get the underlying atomic counter that backs the refcount. + /// + /// NOTE: Usage of this function is discouraged as it can circumvent the protections offered by + /// `refcount.h`. If there is no way to achieve the result using APIs in `refcount.h`, then + /// this function can be used. Otherwise consider adding a binding for the required API. + #[inline] + pub fn as_atomic(&self) -> &Atomic<i32> { + let ptr = self.0.get().cast(); + // SAFETY: `refcount_t` is a transparent wrapper of `atomic_t`, which is an atomic 32-bit + // integer that is layout-wise compatible with `Atomic<i32>`. All values are valid for + // `refcount_t`, despite some of the values being considered saturated and "bad". + unsafe { &*ptr } + } + /// Set a refcount's value. #[inline] pub fn set(&self, value: i32) { |