rust: sync: atomic: Add atomic operation helpers over raw pointers
In order to synchronize with C or external, atomic operations over raw
pointers, althought previously there is always an `Atomic::from_ptr()`
to provide a `&Atomic<T>`. However it's more convenient to have helpers
that directly perform atomic operations on raw pointers. Hence a few are
added, which are basically a `Atomic::from_ptr().op()` wrapper.
Note: for naming, since `atomic_xchg()` and `atomic_cmpxchg()` has a
conflict naming to 32bit C atomic xchg/cmpxchg, hence they are just
named as `xchg()` and `cmpxchg()`. For `atomic_load()` and
`atomic_store()`, their 32bit C counterparts are `atomic_read()` and
`atomic_set()`, so keep the `atomic_` prefix.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2 files changed
