Commit-ID: 1f7870dd8729c64b8472b42440811e7ff94d16a4
Gitweb: http://git.kernel.org/tip/1f7870dd8729c64b8472b42440811e7ff94d16a4
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Sun, 19 Oct 2014 12:05:22 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 13 Nov 2014 10:34:54 -0800
documentation: Add atomic_long_t to atomic_ops.txt
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
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 68542fe..183e41b 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; };
--
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