linux-kernel - [PATCH v5 7/9] perf auxtrace: Remove auxtrace_mmap__read_snapshot

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Message-Id: <20210809111407.596077-8-leo.yan@linaro.org>
Date:   Mon,  9 Aug 2021 19:14:05 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Michael Petlan <mpetlan@...hat.com>,
        "Frank Ch. Eigler" <fche@...hat.com>,
        Song Liu <songliubraving@...com>, x86@...nel.org,
        Daniel Díaz <daniel.diaz@...aro.org>,
        Andrii Nakryiko <andriin@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v5 7/9] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()

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@...aro.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