From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
Although the atomic_long_t functions are quite useful, they are a bit
obscure. This commit therefore adds the common ones alongside their
atomic_t counterparts in Documentation/memory-barriers.txt.
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: David Howells <dhowe...@redhat.com>
---
Documentation/memory-barriers.txt | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/Documentation/memory-barriers.txt
b/Documentation/memory-barriers.txt
index 1d067235b0bc..2d22da095a60 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -1728,21 +1728,23 @@ explicit lock operations, described later). These
include:
xchg();
cmpxchg();
- atomic_xchg();
- atomic_cmpxchg();
- atomic_inc_return();
- atomic_dec_return();
- atomic_add_return();
- atomic_sub_return();
- atomic_inc_and_test();
- atomic_dec_and_test();
- atomic_sub_and_test();
- atomic_add_negative();
- atomic_add_unless(); /* when succeeds (returns 1) */
+ 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();
+ atomic_sub_return(); atomic_long_sub_return();
+ atomic_inc_and_test(); atomic_long_inc_and_test();
+ atomic_dec_and_test(); atomic_long_dec_and_test();
+ atomic_sub_and_test(); atomic_long_sub_and_test();
+ atomic_add_negative(); atomic_long_add_negative();
test_and_set_bit();
test_and_clear_bit();
test_and_change_bit();
+ /* when succeeds (returns 1) */
+ atomic_add_unless(); atomic_long_add_unless();
+
These are used for such things as implementing LOCK-class and UNLOCK-class
operations and adjusting reference counters towards object destruction, and as
such the implicit memory barrier effects are necessary.
--
1.8.1.5
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