Add atomic load wrappers, atomic_cond_read_*_timeout() and atomic64_cond_read_*_timeout() for the cond-load timeout interfaces. Also add a short description for the atomic_cond_read_{relaxed,acquire}(), and the atomic_cond_read_{relaxed,acquire}_timeout() interfaces. Cc: Will Deacon Cc: Peter Zijlstra Cc: Boqun Feng Signed-off-by: Ankur Arora --- Notes: - mention these interfaces in Documentation/atomic_t.txt Documentation/atomic_t.txt | 14 +++++++++----- include/linux/atomic.h | 10 ++++++++++ 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/Documentation/atomic_t.txt b/Documentation/atomic_t.txt index bee3b1bca9a7..0e53f6ccb558 100644 --- a/Documentation/atomic_t.txt +++ b/Documentation/atomic_t.txt @@ -16,6 +16,10 @@ Non-RMW ops: atomic_read(), atomic_set() atomic_read_acquire(), atomic_set_release() +Non-RMW, non-atomic_t ops: + + atomic_cond_read_{relaxed,acquire}() + atomic_cond_read_{relaxed,acquire}_timeout() RMW atomic operations: @@ -79,11 +83,11 @@ SEMANTICS Non-RMW ops: -The non-RMW ops are (typically) regular LOADs and STOREs and are canonically -implemented using READ_ONCE(), WRITE_ONCE(), smp_load_acquire() and -smp_store_release() respectively. Therefore, if you find yourself only using -the Non-RMW operations of atomic_t, you do not in fact need atomic_t at all -and are doing it wrong. +The non-RMW ops are (typically) regular, or conditional LOADs and STOREs and +are canonically implemented using READ_ONCE(), WRITE_ONCE(), +smp_load_acquire() and smp_store_release() respectively. Therefore, if you +find yourself only using the Non-RMW operations of atomic_t, you do not in +fact need atomic_t at all and are doing it wrong. A note for the implementation of atomic_set{}() is that it must not break the atomicity of the RMW ops. That is: diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 8dd57c3a99e9..5bcb86e07784 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -31,6 +31,16 @@ #define atomic64_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c)) #define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) +#define atomic_cond_read_acquire_timeout(v, c, e, t) \ + smp_cond_load_acquire_timeout(&(v)->counter, (c), (e), (t)) +#define atomic_cond_read_relaxed_timeout(v, c, e, t) \ + smp_cond_load_relaxed_timeout(&(v)->counter, (c), (e), (t)) + +#define atomic64_cond_read_acquire_timeout(v, c, e, t) \ + smp_cond_load_acquire_timeout(&(v)->counter, (c), (e), (t)) +#define atomic64_cond_read_relaxed_timeout(v, c, e, t) \ + smp_cond_load_relaxed_timeout(&(v)->counter, (c), (e), (t)) + /* * The idea here is to build acquire/release variants by adding explicit * barriers on top of the relaxed variant. In the case where the relaxed -- 2.31.1