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>

7 files changed, 313 insertions, 182 deletions

diff --git a/tools/perf/pmu-events/empty-pmu-events.c b/tools/perf/pmu-events/empty-pmu-events.c
index 028f44efe48d..bee1967baa2b 100644
--- a/tools/perf/pmu-events/empty-pmu-events.c
+++ b/tools/perf/pmu-events/empty-pmu-events.c
@@ -247,6 +247,20 @@ static const struct pmu_sys_events pmu_sys_event_tables[] = {
 	},
 };
 
+int pmu_events_table_for_each_event(const struct pmu_event *table, pmu_event_iter_fn fn,
+				    void *data)
+{
+	for (const struct pmu_event *pe = &table[0];
+	     pe->name || pe->metric_group || pe->metric_name;
+	     pe++) {
+		int ret = fn(pe, table, data);
+
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 const struct pmu_event *perf_pmu__find_table(struct perf_pmu *pmu)
 {
 	const struct pmu_event *table = NULL;
@@ -291,14 +305,10 @@ int pmu_for_each_core_event(pmu_event_iter_fn fn, void *data)
 	for (const struct pmu_events_map *tables = &pmu_events_map[0];
 	     tables->table;
 	     tables++) {
-		for (const struct pmu_event *pe = &tables->table[0];
-		     pe->name || pe->metric_group || pe->metric_name;
-		     pe++) {
-			int ret = fn(pe, &tables->table[0], data);
+		int ret = pmu_events_table_for_each_event(tables->table, fn, data);
 
-			if (ret)
-				return ret;
-		}
+		if (ret)
+			return ret;
 	}
 	return 0;
 }
@@ -319,14 +329,10 @@ int pmu_for_each_sys_event(pmu_event_iter_fn fn, void *data)
 	for (const struct pmu_sys_events *tables = &pmu_sys_event_tables[0];
 	     tables->name;
 	     tables++) {
-		for (const struct pmu_event *pe = &tables->table[0];
-		     pe->name || pe->metric_group || pe->metric_name;
-		     pe++) {
-			int ret = fn(pe, &tables->table[0], data);
+		int ret = pmu_events_table_for_each_event(tables->table, fn, data);
 
-			if (ret)
-				return ret;
-		}
+		if (ret)
+			return ret;
 	}
 	return 0;
 }
diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py
index 1a04b848d736..977f2061a990 100755
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -410,6 +410,20 @@ static const struct pmu_sys_events pmu_sys_event_tables[] = {
 \t},
 };
 
+int pmu_events_table_for_each_event(const struct pmu_event *table, pmu_event_iter_fn fn,
+                                    void *data)
+{
+        for (const struct pmu_event *pe = &table[0];
+             pe->name || pe->metric_group || pe->metric_name;
+             pe++) {
+                int ret = fn(pe, table, data);
+
+                if (ret)
+                        return ret;
+        }
+        return 0;
+}
+
 const struct pmu_event *perf_pmu__find_table(struct perf_pmu *pmu)
 {
         const struct pmu_event *table = NULL;
@@ -453,14 +467,10 @@ int pmu_for_each_core_event(pmu_event_iter_fn fn, void *data)
         for (const struct pmu_events_map *tables = &pmu_events_map[0];
              tables->table;
              tables++) {
-                for (const struct pmu_event *pe = &tables->table[0];
-                     pe->name || pe->metric_group || pe->metric_name;
-                     pe++) {
-                        int ret = fn(pe, &tables->table[0], data);
+                int ret = pmu_events_table_for_each_event(tables->table, fn, data);
 
-                        if (ret)
-                                return ret;
-                }
+                if (ret)
+                        return ret;
         }
         return 0;
 }
@@ -481,14 +491,10 @@ int pmu_for_each_sys_event(pmu_event_iter_fn fn, void *data)
         for (const struct pmu_sys_events *tables = &pmu_sys_event_tables[0];
              tables->name;
              tables++) {
-                for (const struct pmu_event *pe = &tables->table[0];
-                     pe->name || pe->metric_group || pe->metric_name;
-                     pe++) {
-                        int ret = fn(pe, &tables->table[0], data);
+                int ret = pmu_events_table_for_each_event(tables->table, fn, data);
 
-                        if (ret)
-                                return ret;
-                }
+                if (ret)
+                        return ret;
         }
         return 0;
 }
diff --git a/tools/perf/pmu-events/pmu-events.h b/tools/perf/pmu-events/pmu-events.h
index 485e730f9922..70672842f77f 100644
--- a/tools/perf/pmu-events/pmu-events.h
+++ b/tools/perf/pmu-events/pmu-events.h
@@ -34,6 +34,9 @@ typedef int (*pmu_event_iter_fn)(const struct pmu_event *pe,
 				 const struct pmu_event *table,
 				 void *data);
 
+int pmu_events_table_for_each_event(const struct pmu_event *table, pmu_event_iter_fn fn,
+				    void *data);
+
 const struct pmu_event *perf_pmu__find_table(struct perf_pmu *pmu);
 const struct pmu_event *find_core_events_table(const char *arch, const char *cpuid);
 int pmu_for_each_core_event(pmu_event_iter_fn fn, void *data);
diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
index a64497cb9fb2..e308d480f0fb 100644
--- a/tools/perf/tests/pmu-events.c
+++ b/tools/perf/tests/pmu-events.c
@@ -423,84 +423,104 @@ static int compare_alias_to_test_event(struct perf_pmu_alias *alias,
 	return 0;
 }
 
-/* Verify generated events from pmu-events.c are as expected */
-static int test__pmu_event_table(struct test_suite *test __maybe_unused,
-				 int subtest __maybe_unused)
+static int test__pmu_event_table_core_callback(const struct pmu_event *pe,
+					       const struct pmu_event *table __maybe_unused,
+					       void *data)
 {
-	const struct pmu_event *sys_event_tables = find_sys_events_table("pme_test_soc_sys");
-	const struct pmu_event *table = find_core_events_table("testarch", "testcpu");
-	int map_events = 0, expected_events;
+	int *map_events = data;
+	struct perf_pmu_test_event const **test_event_table;
+	bool found = false;
 
-	/* ignore 3x sentinels */
-	expected_events = ARRAY_SIZE(core_events) +
-			  ARRAY_SIZE(uncore_events) +
-			  ARRAY_SIZE(sys_events) - 3;
+	if (!pe->name)
+		return 0;
 
-	if (!table || !sys_event_tables)
-		return -1;
+	if (pe->pmu)
+		test_event_table = &uncore_events[0];
+	else
+		test_event_table = &core_events[0];
 
-	for (; table->name; table++) {
-		struct perf_pmu_test_event const **test_event_table;
-		bool found = false;
+	for (; *test_event_table; test_event_table++) {
+		struct perf_pmu_test_event const *test_event = *test_event_table;
+		struct pmu_event const *event = &test_event->event;
 
-		if (table->pmu)
-			test_event_table = &uncore_events[0];
-		else
-			test_event_table = &core_events[0];
+		if (strcmp(pe->name, event->name))
+			continue;
+		found = true;
+		(*map_events)++;
 
-		for (; *test_event_table; test_event_table++) {
-			struct perf_pmu_test_event const *test_event = *test_event_table;
-			struct pmu_event const *event = &test_event->event;
+		if (compare_pmu_events(pe, event))
+			return -1;
 
-			if (strcmp(table->name, event->name))
-				continue;
-			found = true;
-			map_events++;
+		pr_debug("testing event table %s: pass\n", pe->name);
+	}
+	if (!found) {
+		pr_err("testing event table: could not find event %s\n", pe->name);
+		return -1;
+	}
+	return 0;
+}
 
-			if (compare_pmu_events(table, event))
-				return -1;
+static int test__pmu_event_table_sys_callback(const struct pmu_event *pe,
+					      const struct pmu_event *table __maybe_unused,
+					      void *data)
+{
+	int *map_events = data;
+	struct perf_pmu_test_event const **test_event_table;
+	bool found = false;
 
-			pr_debug("testing event table %s: pass\n", table->name);
-		}
+	test_event_table = &sys_events[0];
 
-		if (!found) {
-			pr_err("testing event table: could not find event %s\n",
-			       table->name);
-			return -1;
-		}
-	}
+	for (; *test_event_table; test_event_table++) {
+		struct perf_pmu_test_event const *test_event = *test_event_table;
+		struct pmu_event const *event = &test_event->event;
 
-	for (table = sys_event_tables; table->name; table++) {
-		struct perf_pmu_test_event const **test_event_table;
-		bool found = false;
+		if (strcmp(pe->name, event->name))
+			continue;
+		found = true;
+		(*map_events)++;
 
-		test_event_table = &sys_events[0];
+		if (compare_pmu_events(pe, event))
+			return TEST_FAIL;
 
-		for (; *test_event_table; test_event_table++) {
-			struct perf_pmu_test_event const *test_event = *test_event_table;
-			struct pmu_event const *event = &test_event->event;
+		pr_debug("testing sys event table %s: pass\n", pe->name);
+	}
+	if (!found) {
+		pr_debug("testing sys event table: could not find event %s\n", pe->name);
+		return TEST_FAIL;
+	}
+	return TEST_OK;
+}
 
-			if (strcmp(table->name, event->name))
-				continue;
-			found = true;
-			map_events++;
+/* Verify generated events from pmu-events.c are as expected */
+static int test__pmu_event_table(struct test_suite *test __maybe_unused,
+				 int subtest __maybe_unused)
+{
+	const struct pmu_event *sys_event_table = find_sys_events_table("pme_test_soc_sys");
+	const struct pmu_event *table = find_core_events_table("testarch", "testcpu");
+	int map_events = 0, expected_events, err;
 
-			if (compare_pmu_events(table, event))
-				return -1;
+	/* ignore 3x sentinels */
+	expected_events = ARRAY_SIZE(core_events) +
+			  ARRAY_SIZE(uncore_events) +
+			  ARRAY_SIZE(sys_events) - 3;
 
-			pr_debug("testing sys event table %s: pass\n", table->name);
-		}
-		if (!found) {
-			pr_debug("testing event table: could not find event %s\n",
-				   table->name);
-			return -1;
-		}
-	}
+	if (!table || !sys_event_table)
+		return -1;
+
+	err = pmu_events_table_for_each_event(table, test__pmu_event_table_core_callback,
+					      &map_events);
+	if (err)
+		return err;
+
+	err = pmu_events_table_for_each_event(sys_event_table, test__pmu_event_table_sys_callback,
+					      &map_events);
+	if (err)
+		return err;
 
 	if (map_events != expected_events) {
 		pr_err("testing event table: found %d, but expected %d\n",
 		       map_events, expected_events);
-		return -1;
+		return TEST_FAIL;
 	}
 
 	return 0;
diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 8d994539d6ea..cae97b6dc5bc 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -538,12 +538,40 @@ static int metricgroup__print_sys_event_iter(const struct pmu_event *pe,
 				     d->details, d->groups, d->metriclist);
 }
 
+struct metricgroup_print_data {
+	const char *pmu_name;
+	struct strlist *metriclist;
+	char *filter;
+	struct rblist *groups;
+	bool metricgroups;
+	bool raw;
+	bool details;
+};
+
+static int metricgroup__print_callback(const struct pmu_event *pe,
+				       const struct pmu_event *table __maybe_unused,
+				       void *vdata)
+{
+	struct metricgroup_print_data *data = vdata;
+
+	if (!pe->metric_expr)
+		return 0;
+
+	if (data->pmu_name && perf_pmu__is_hybrid(pe->pmu) && strcmp(data->pmu_name, pe->pmu))
+		return 0;
+
+	return metricgroup__print_pmu_event(pe, data->metricgroups, data->filter,
+					    data->raw, data->details, data->groups,
+					    data->metriclist);
+}
+
 void metricgroup__print(bool metrics, bool metricgroups, char *filter,
 			bool raw, bool details, const char *pmu_name)
 {
 	struct rblist groups;
 	struct rb_node *node, *next;
 	struct strlist *metriclist = NULL;
+	const struct pmu_event *table;
 
 	if (!metricgroups) {
 		metriclist = strlist__new(NULL, NULL);
@@ -555,22 +583,22 @@ void metricgroup__print(bool metrics, bool metricgroups, char *filter,
 	groups.node_new = mep_new;
 	groups.node_cmp = mep_cmp;
 	groups.node_delete = mep_delete;
-	for (const struct pmu_event *pe = pmu_events_table__find(); pe; pe++) {
+	table = pmu_events_table__find();
+	if (table) {
+		struct metricgroup_print_data data = {
+			.pmu_name = pmu_name,
+			.metriclist = metriclist,
+			.metricgroups = metricgroups,
+			.filter = filter,
+			.raw = raw,
+			.details = details,
+			.groups = &groups,
+		};
 
-		if (!pe->name && !pe->metric_group && !pe->metric_name)
-			break;
-		if (!pe->metric_expr)
-			continue;
-		if (pmu_name && perf_pmu__is_hybrid(pe->pmu) &&
-		    strcmp(pmu_name, pe->pmu)) {
-			continue;
-		}
-		if (metricgroup__print_pmu_event(pe, metricgroups, filter,
-						 raw, details, &groups,
-						 metriclist) < 0)
-			return;
+		pmu_events_table_for_each_event(table,
+						metricgroup__print_callback,
+						&data);
 	}
-
 	{
 		struct metricgroup_iter_data data = {
 			.fn = metricgroup__print_sys_event_iter,
@@ -1043,30 +1071,35 @@ static int __add_metric(struct list_head *metric_list,
 	return ret;
 }
 
-#define table_for_each_event(__pe, __idx, __table)					\
-	if (__table)								\
-		for (__idx = 0, __pe = &__table[__idx];				\
-		     __pe->name || __pe->metric_group || __pe->metric_name;	\
-		     __pe = &__table[++__idx])
+struct metricgroup__find_metric_data {
+	const char *metric;
+	const struct pmu_event *pe;
+};
+
+static int metricgroup__find_metric_callback(const struct pmu_event *pe,
+					     const struct pmu_event *table  __maybe_unused,
+					     void *vdata)
+{
+	struct metricgroup__find_metric_data *data = vdata;
+
+	if (!match_metric(pe->metric_name, data->metric))
+		return 0;
 
-#define table_for_each_metric(__pe, __idx, __table, __metric)		\
-	table_for_each_event(__pe, __idx, __table)				\
-		if (__pe->metric_expr &&				\
-		    (match_metric(__pe->metric_group, __metric) ||	\
-		     match_metric(__pe->metric_name, __metric)))
+	data->pe = pe;
+	return -1;
+}
 
 const struct pmu_event *metricgroup__find_metric(const char *metric,
 						 const struct pmu_event *table)
 {
-	const struct pmu_event *pe;
-	int i;
+	struct metricgroup__find_metric_data data = {
+		.metric = metric,
+		.pe = NULL,
+	};
 
-	table_for_each_event(pe, i, table) {
-		if (match_metric(pe->metric_name, metric))
-			return pe;
-	}
+	pmu_events_table_for_each_event(table, metricgroup__find_metric_callback, &data);
 
-	return NULL;
+	return data.pe;
 }
 
 static int add_metric(struct list_head *metric_list,
@@ -1151,6 +1184,33 @@ static int metric_list_cmp(void *priv __maybe_unused, const struct list_head *l,
 	return right_count - left_count;
 }
 
+struct metricgroup__add_metric_data {
+	struct list_head *list;
+	const char *metric_name;
+	const char *modifier;
+	bool metric_no_group;
+	bool has_match;
+};
+
+static int metricgroup__add_metric_callback(const struct pmu_event *pe,
+					    const struct pmu_event *table,
+					    void *vdata)
+{
+	struct metricgroup__add_metric_data *data = vdata;
+	int ret = 0;
+
+	if (pe->metric_expr &&
+		(match_metric(pe->metric_group, data->metric_name) ||
+		 match_metric(pe->metric_name, data->metric_name))) {
+
+		data->has_match = true;
+		ret = add_metric(data->list, pe, data->modifier, data->metric_no_group,
+				 /*root_metric=*/NULL,
+				 /*visited_metrics=*/NULL, table);
+	}
+	return ret;
+}
+
 /**
  * metricgroup__add_metric - Find and add a metric, or a metric group.
  * @metric_name: The name of the metric or metric group. For example, "IPC"
@@ -1169,24 +1229,29 @@ static int metricgroup__add_metric(const char *metric_name, const char *modifier
 				   struct list_head *metric_list,
 				   const struct pmu_event *table)
 {
-	const struct pmu_event *pe;
 	LIST_HEAD(list);
-	int i, ret;
+	int ret;
 	bool has_match = false;
 
-	/*
-	 * Iterate over all metrics seeing if metric matches either the name or
-	 * group. When it does add the metric to the list.
-	 */
-	table_for_each_metric(pe, i, table, metric_name) {
-		has_match = true;
-		ret = add_metric(&list, pe, modifier, metric_no_group,
-				 /*root_metric=*/NULL,
-				 /*visited_metrics=*/NULL, table);
+	{
+		struct metricgroup__add_metric_data data = {
+			.list = &list,
+			.metric_name = metric_name,
+			.modifier = modifier,
+			.metric_no_group = metric_no_group,
+			.has_match = false,
+		};
+		/*
+		 * Iterate over all metrics seeing if metric matches either the
+		 * name or group. When it does add the metric to the list.
+		 */
+		ret = pmu_events_table_for_each_event(table, metricgroup__add_metric_callback,
+						      &data);
 		if (ret)
 			goto out;
-	}
 
+		has_match = data.has_match;
+	}
 	{
 		struct metricgroup_iter_data data = {
 			.fn = metricgroup__add_metric_sys_event_iter,
@@ -1602,26 +1667,30 @@ int metricgroup__parse_groups_test(struct evlist *evlist,
 			    metric_no_merge, &perf_pmu__fake, metric_events, table);
 }
 
+static int metricgroup__has_metric_callback(const struct pmu_event *pe,
+					    const struct pmu_event *table __maybe_unused,
+					    void *vdata)
+{
+	const char *metric = vdata;
+
+	if (!pe->metric_expr)
+		return 0;
+
+	if (match_metric(pe->metric_name, metric))
+		return 1;
+
+	return 0;
+}
+
 bool metricgroup__has_metric(const char *metric)
 {
 	const struct pmu_event *table = pmu_events_table__find();
-	const struct pmu_event *pe;
-	int i;
 
 	if (!table)
 		return false;
 
-	for (i = 0; ; i++) {
-		pe = &table[i];
-
-		if (!pe->name && !pe->metric_group && !pe->metric_name)
-			break;
-		if (!pe->metric_expr)
-			continue;
-		if (match_metric(pe->metric_name, metric))
-			return true;
-	}
-	return false;
+	return pmu_events_table_for_each_event(table, metricgroup__has_metric_callback,
+					       (void *)metric) ? true : false;
 }
 
 int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index f117324eb5f0..dd1e171d7480 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -791,6 +791,36 @@ out:
 	return res;
 }
 
+struct pmu_add_cpu_aliases_map_data {
+	struct list_head *head;
+	const char *name;
+	const char *cpu_name;
+	struct perf_pmu *pmu;
+};
+
+static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
+					const struct pmu_event *table __maybe_unused,
+					void *vdata)
+{
+	struct pmu_add_cpu_aliases_map_data *data = vdata;
+	const char *pname = pe->pmu ? pe->pmu : data->cpu_name;
+
+	if (!pe->name)
+		return 0;
+
+	if (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->name))
+		goto new_alias;
+
+	if (strcmp(pname, data->name))
+		return 0;
+
+new_alias:
+	/* need type casts to override 'const' */
+	__perf_pmu__new_alias(data->head, NULL, (char *)pe->name, (char *)pe->desc,
+			      (char *)pe->event, pe);
+	return 0;
+}
+
 /*
  * From the pmu_events_map, find the table of PMU events that corresponds
  * to the current running CPU. Then, add all PMU events from that table
@@ -799,35 +829,14 @@ out:
 void pmu_add_cpu_aliases_table(struct list_head *head, struct perf_pmu *pmu,
 			       const struct pmu_event *table)
 {
-	int i;
-	const char *name = pmu->name;
-	/*
-	 * Found a matching PMU events table. Create aliases
-	 */
-	i = 0;
-	while (1) {
-		const char *cpu_name = is_arm_pmu_core(name) ? name : "cpu";
-		const struct pmu_event *pe = &table[i++];
-		const char *pname = pe->pmu ? pe->pmu : cpu_name;
-
-		if (!pe->name) {
-			if (pe->metric_group || pe->metric_name)
-				continue;
-			break;
-		}
-
-		if (pmu->is_uncore && pmu_uncore_alias_match(pname, name))
-			goto new_alias;
-
-		if (strcmp(pname, name))
-			continue;
+	struct pmu_add_cpu_aliases_map_data data = {
+		.head = head,
+		.name = pmu->name,
+		.cpu_name = is_arm_pmu_core(pmu->name) ? pmu->name : "cpu",
+		.pmu = pmu,
+	};
 
-new_alias:
-		/* need type casts to override 'const' */
-		__perf_pmu__new_alias(head, NULL, (char *)pe->name,
-				(char *)pe->desc, (char *)pe->event,
-				pe);
-	}
+	pmu_events_table_for_each_event(table, pmu_add_cpu_aliases_map_callback, &data);
 }
 
 static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
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)