[PATCH v5 7/9] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()

From: Leo Yan <leo.yan@linaro.org>
To: "Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Jiri Olsa" <jolsa@redhat.com>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Mathieu Poirier" <mathieu.poirier@linaro.org>,
	"Suzuki K Poulose" <suzuki.poulose@arm.com>,
	"Mike Leach" <mike.leach@linaro.org>,
	"Michael Petlan" <mpetlan@redhat.com>,
	"Frank Ch. Eigler" <fche@redhat.com>,
	"Song Liu" <songliubraving@fb.com>,
	x86@kernel.org, "Daniel Díaz" <daniel.diaz@linaro.org>,
	"Andrii Nakryiko" <andriin@fb.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Sedat Dilek" <sedat.dilek@gmail.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v5 7/9] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()
Date: Mon,  9 Aug 2021 19:14:05 +0800	[thread overview]
Message-ID: <20210809111407.596077-8-leo.yan@linaro.org> (raw)
In-Reply-To: <20210809111407.596077-1-leo.yan@linaro.org>

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@linaro.org>
---
 tools/perf/util/auxtrace.c | 13 +++++--------
 tools/perf/util/auxtrace.h | 10 ----------
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index cb19669d2a5b..2dcf3d12ba32 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1686,14 +1686,11 @@ static int __auxtrace_mmap__read(struct mmap *map,
 	union perf_event ev;
 	void *data1, *data2;
 
-	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);
-	}
+	head = auxtrace_mmap__read_head(mm);
+
+	if (snapshot &&
+	    auxtrace_record__find_snapshot(itr, mm->idx, mm, data, &head, &old))
+		return -1;
 
 	if (old == head)
 		return 0;
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

