libperf: Fix perf_cpu_map__for_each_cpu macro

Tzvetomir Stoyanov reported an issue with using macro
perf_cpu_map__for_each_cpu using private perf_cpu object.

The issue is caused by recent change that wrapped cpu in struct perf_cpu
to distinguish it from cpu indexes. We need to make struct perf_cpu
public.

Add a simple test for using the perf_cpu_map__for_each_cpu macro.

Fixes: 6d18804b ("perf cpumap: Give CPUs their own type")
Reported-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220215153713.31395-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/perf/include/internal/cpumap.h

@@ -3,11 +3,7 @@
 #define __LIBPERF_INTERNAL_CPUMAP_H
 
 #include <linux/refcount.h>
-
-/** A wrapper around a CPU to avoid confusion with the perf_cpu_map's map's indices. */
-struct perf_cpu {
-	int cpu;
-};
+#include <perf/cpumap.h>
 
 /**
  * A sized, reference counted, sorted array of integers representing CPU

tools/lib/perf/include/perf/cpumap.h

@@ -7,6 +7,11 @@
 #include <stdio.h>
 #include <stdbool.h>
 
+/** A wrapper around a CPU to avoid confusion with the perf_cpu_map's map's indices. */
+struct perf_cpu {
+	int cpu;
+};
+
 LIBPERF_API struct perf_cpu_map *perf_cpu_map__dummy_new(void);
 LIBPERF_API struct perf_cpu_map *perf_cpu_map__default_new(void);
 LIBPERF_API struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list);

tools/lib/perf/libperf.map

@@ -2,6 +2,7 @@ LIBPERF_0.0.1 {
 	global:
 		libperf_init;
 		perf_cpu_map__dummy_new;
+		perf_cpu_map__default_new;
 		perf_cpu_map__get;
 		perf_cpu_map__put;
 		perf_cpu_map__new;

tools/lib/perf/tests/test-cpumap.c

@@ -14,6 +14,8 @@ static int libperf_print(enum libperf_print_level level,
 int test_cpumap(int argc, char **argv)
 {
 	struct perf_cpu_map *cpus;
+	struct perf_cpu cpu;
+	int idx;
 
 	__T_START;
 
@@ -27,6 +29,15 @@ int test_cpumap(int argc, char **argv)
 	perf_cpu_map__put(cpus);
 	perf_cpu_map__put(cpus);
 
+	cpus = perf_cpu_map__default_new();
+	if (!cpus)
+		return -1;
+
+	perf_cpu_map__for_each_cpu(cpu, idx, cpus)
+		__T("wrong cpu number", cpu.cpu != -1);
+
+	perf_cpu_map__put(cpus);
+
 	__T_END;
 	return tests_failed == 0 ? 0 : -1;
 }