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Currently the > > kernel refcount has already been used in `Arc`, however it calls into > > FFI directly. > > > > Reviewed-by: Alice Ryhl > > Reviewed-by: Boqun Feng > > Reviewed-by: Fiona Behrens > > Signed-off-by: Gary Guo > > Reviewed-by: Benno Lossin > > > --- > > rust/helpers/refcount.c | 10 ++++ > > rust/kernel/sync.rs | 2 + > > rust/kernel/sync/refcount.rs | 98 ++++++++++++++++++++++++++++++++++++ > > 3 files changed, 110 insertions(+) > > create mode 100644 rust/kernel/sync/refcount.rs > > > + #[inline] > > + fn as_ptr(&self) -> *mut bindings::refcount_t { > > I think we should make this `pub(crate)` from the get-go. I think it's probably fine as is. I think this method won't be useful outside this module unless people add a `from_ptr` later. But I'm also fine changing this. Best, Gary > > > + self.0.get() > > + } > > + > > > + /// Decrement a refcount and test if it is 0. > > + /// > > + /// It will `WARN` on underflow and fail to decrement when saturated. > > + /// > > + /// Provides release memory ordering, such that prior loads and stores are done > > + /// before, and provides an acquire ordering on success such that memory deallocation > > + /// must come after. > > + /// > > + /// Returns true if the resulting refcount is 0, false otherwise. > > + /// > > + /// # Notes > > + /// > > + /// A common pattern of using `Refcount` is to free memory when the reference count reaches > > + /// zero. This means that the reference to `Refcount` could become invalid after calling this > > + /// function. This is fine as long as the reference to `Refcount` is no longer used when this > > + /// function returns `false`. It is not necessary to use raw pointers in this scenario, see > > + /// https://github.com/rust-lang/rust/issues/55005. > > Missing `<>` around link. > > --- > Cheers, > Benno