doc: Fix memory-barrier control-dependency example
Each control-dependency example needs its barriers between the "if"
condition and the body of the "if" because a control dependency is
a dependency induced by a branch. This commit makes the needed
adjustment.
Reported-by: Yongming Shen <symingz@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index fa5d8a9..c8c42e6 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -531,9 +531,10 @@
code:
q = &a;
- if (p)
+ if (p) {
+ <data dependency barrier>
q = &b;
- <data dependency barrier>
+ }
x = *q;
This will not have the desired effect because there is no actual data
@@ -542,9 +543,10 @@
required is:
q = &a;
- if (p)
+ if (p) {
+ <read barrier>
q = &b;
- <read barrier>
+ }
x = *q;
