[PATCH v4 07/11] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()

[Leo Yan]

Since the function auxtrace_mmap__read_snapshot_head() is exactly same
with auxtrace_mmap__read_head(), whether the session is in snapshot mode
or not, it's unified to use function auxtrace_mmap__read_head() for
reading AUX buffer head.

And the function auxtrace_mmap__read_snapshot_head() is unused so this
patch removes it.

Signed-off-by: Leo Yan <leo.yan at linaro.org>
---
 tools/perf/util/auxtrace.c |  5 ++---
 tools/perf/util/auxtrace.h | 10 ----------
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index cb19669d2a5b..7958e17229ea 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1686,13 +1686,12 @@ static int __auxtrace_mmap__read(struct mmap *map,
 	union perf_event ev;
 	void *data1, *data2;
 
+	head = auxtrace_mmap__read_head(mm);
+
 	if (snapshot) {
-		head = auxtrace_mmap__read_snapshot_head(mm);
 		if (auxtrace_record__find_snapshot(itr, mm->idx, mm, data,
 						   &head, &old))
 			return -1;
-	} else {
-		head = auxtrace_mmap__read_head(mm);
 	}
 
 	if (old == head)
diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index 4f9176368134..d68a5e80b217 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -440,16 +440,6 @@ struct auxtrace_cache;
 
 #ifdef HAVE_AUXTRACE_SUPPORT
 
-static inline u64 auxtrace_mmap__read_snapshot_head(struct auxtrace_mmap *mm)
-{
-	struct perf_event_mmap_page *pc = mm->userpg;
-	u64 head = READ_ONCE(pc->aux_head);
-
-	/* Ensure all reads are done after we read the head */
-	smp_rmb();
-	return head;
-}
-
 static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
 {
 	struct perf_event_mmap_page *pc = mm->userpg;
-- 
2.25.1