locking/Documentation: Clarify failed cmpxchg() memory ordering semantics

[deliverable/linux.git] / Documentation / memory-barriers.txt

diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 13feb697271f0a270334dd3807255ed14af7d7ed..18fc860df1beeafe93abfb50060957144697a6b4 100644 (file)
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -2383,9 +2383,7 @@ about the state (old or new) implies an SMP-conditional general memory barrier
 explicit lock operations, described later).  These include:
 
        xchg();
-       cmpxchg();
        atomic_xchg();                  atomic_long_xchg();
-       atomic_cmpxchg();               atomic_long_cmpxchg();
        atomic_inc_return();            atomic_long_inc_return();
        atomic_dec_return();            atomic_long_dec_return();
        atomic_add_return();            atomic_long_add_return();
@@ -2398,7 +2396,9 @@ explicit lock operations, described later).  These include:
        test_and_clear_bit();
        test_and_change_bit();
 
-       /* when succeeds (returns 1) */
+       /* when succeeds */
+       cmpxchg();
+       atomic_cmpxchg();               atomic_long_cmpxchg();
        atomic_add_unless();            atomic_long_add_unless();
 
 These are used for such things as implementing ACQUIRE-class and RELEASE-class