tools/memory-model: Make read_foo_diagnostic() more clearly diagnostic

The current definition of read_foo_diagnostic() in the "Lock Protection
With Lockless Diagnostic Access" section returns a value, which could
be use for any purpose.  This could mislead people into incorrectly
using data_race() in cases where READ_ONCE() is required.  This commit
therefore makes read_foo_diagnostic() simply print the value read.

Reported-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/tools/memory-model/Documentation/access-marking.txt b/tools/memory-model/Documentation/access-marking.txt
index 1ab189f..58bff26 100644 (file)
--- a/tools/memory-model/Documentation/access-marking.txt
+++ b/tools/memory-model/Documentation/access-marking.txt
@@ -259,9 +259,9 @@ diagnostic purposes.  The code might look as follows:
                return ret;
        }
 
-       int read_foo_diagnostic(void)
+       void read_foo_diagnostic(void)
        {
-               return data_race(foo);
+               pr_info("Current value of foo: %d\n", data_race(foo));
        }
 
 The reader-writer lock prevents the compiler from introducing concurrency