perf pmu-events: Don't assume pmu_event is an array

The current code assumes that a struct pmu_event can be iterated over
forward until a NULL pmu_event is encountered.

This makes it difficult to refactor pmu_event.

Add a loop function taking a callback function that's passed the struct
pmu_event.

This way the pmu_event is only needed for one element and not an entire
array.

Switch existing code iterating over the pmu_event arrays to use the new
loop function pmu_events_table_for_each_event.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20220812230949.683239-11-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 30 insertions, 12 deletions

diff --git a/tools/perf/util/s390-sample-raw.c b/tools/perf/util/s390-sample-raw.c
index dddd2be59827..235319d45d02 100644
--- a/tools/perf/util/s390-sample-raw.c
+++ b/tools/perf/util/s390-sample-raw.c
@@ -129,6 +129,28 @@ static int get_counterset_start(int setnr)
 	}
 }
 
+struct get_counter_name_data {
+	int wanted;
+	const char *result;
+};
+
+static int get_counter_name_callback(const struct pmu_event *evp,
+				     const struct pmu_event *table __maybe_unused,
+				     void *vdata)
+{
+	struct get_counter_name_data *data = vdata;
+	int rc, event_nr;
+
+	if (evp->name == NULL || evp->event == NULL)
+		return 0;
+	rc = sscanf(evp->event, "event=%x", &event_nr);
+	if (rc == 1 && event_nr == data->wanted) {
+		data->result = evp->name;
+		return 1; /* Terminate the search. */
+	}
+	return 0;
+}
+
 /* Scan the PMU table and extract the logical name of a counter from the
  * PMU events table. Input is the counter set and counter number with in the
  * set. Construct the event number and use this as key. If they match return
@@ -137,20 +159,16 @@ static int get_counterset_start(int setnr)
  */
 static const char *get_counter_name(int set, int nr, const struct pmu_event *table)
 {
-	int rc, event_nr, wanted = get_counterset_start(set) + nr;
+	struct get_counter_name_data data = {
+		.wanted = get_counterset_start(set) + nr,
+		.result = NULL,
+	};
 
-	if (table) {
-		const struct pmu_event *evp = table;
+	if (!table)
+		return NULL;
 
-		for (; evp->name || evp->event || evp->desc; ++evp) {
-			if (evp->name == NULL || evp->event == NULL)
-				continue;
-			rc = sscanf(evp->event, "event=%x", &event_nr);
-			if (rc == 1 && event_nr == wanted)
-				return evp->name;
-		}
-	}
-	return NULL;
+	pmu_events_table_for_each_event(table, get_counter_name_callback, &data);
+	return data.result;
 }
 
 static void s390_cpumcfdg_dump(struct perf_sample *sample)