tools/perf: Convert ACCESS_ONCE() to READ_ONCE()

Recently there was a treewide conversion of ACCESS_ONCE() to
{READ,WRITE}_ONCE(), but a new use was introduced concurrently by
commit:

  1695849735752d2a ("perf mmap: Move perf_mmap and methods to separate mmap.[ch] files")

Let's convert this over to READ_ONCE() so that we can remove the
ACCESS_ONCE() definitions in subsequent patches.

Tested-by: Paul E. McKenney <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index efd78b827b0514275f9388b2c64329c45c025248..3a5cb5a6e94ad8fc039dc3410a6724263057a970 100644 (file)
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -70,7 +70,7 @@ void perf_mmap__read_catchup(struct perf_mmap *md);
 static inline u64 perf_mmap__read_head(struct perf_mmap *mm)
 {
        struct perf_event_mmap_page *pc = mm->base;
-       u64 head = ACCESS_ONCE(pc->data_head);
+       u64 head = READ_ONCE(pc->data_head);
        rmb();
        return head;
 }