From: "Paul E. McKenney" <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
---
Documentation/atomic_ops.txt | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt
index 68542fe13b85..183e41bdcb69 100644
--- a/Documentation/atomic_ops.txt
+++ b/Documentation/atomic_ops.txt
@@ -7,12 +7,13 @@
maintainers on how to implement atomic counter, bitops, and spinlock
interfaces properly.
- The atomic_t type should be defined as a signed integer.
-Also, it should be made opaque such that any kind of cast to a normal
-C integer type will fail. Something like the following should
-suffice:
+ The atomic_t type should be defined as a signed integer and
+the atomic_long_t type as a signed long integer. Also, they should
+be made opaque such that any kind of cast to a normal C integer type
+will fail. Something like the following should suffice:
typedef struct { int counter; } atomic_t;
+ typedef struct { long counter; } atomic_long_t;
Historically, counter has been declared volatile. This is now discouraged.
See Documentation/volatile-considered-harmful.txt for the complete rationale.
@@ -37,6 +38,9 @@ initializer is used before runtime. If the initializer is
used at runtime, a
proper implicit or explicit read memory barrier is needed before reading the
value with atomic_read from another thread.
+As with all of the atomic_ interfaces, replace the leading "atomic_"
+with "atomic_long_" to operate on atomic_long_t.
+
The second interface can be used at runtime, as in:
struct foo { atomic_t counter; };
--
1.8.1.5
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