1 files changed, 49 insertions, 33 deletions

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1a5591d7a245..f5cfed60af98 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -127,59 +127,75 @@ int __perf_evsel__read(struct perf_evsel *evsel,
         return 0;
 }
 
-int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
+static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
+                              struct thread_map *threads)
 {
-        int cpu;
+        int cpu, thread;
 
-        if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, cpus->nr, 1) < 0)
+        if (evsel->fd == NULL &&
+            perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
                 return -1;
 
         for (cpu = 0; cpu < cpus->nr; cpu++) {
-                FD(evsel, cpu, 0) = sys_perf_event_open(&evsel->attr, -1,
-                                                        cpus->map[cpu], -1, 0);
-                if (FD(evsel, cpu, 0) < 0)
-                        goto out_close;
+                for (thread = 0; thread < threads->nr; thread++) {
+                        FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
+                                                                     threads->map[thread],
+                                                                     cpus->map[cpu], -1, 0);
+                        if (FD(evsel, cpu, thread) < 0)
+                                goto out_close;
+                }
         }
 
         return 0;
 
 out_close:
-        while (--cpu >= 0) {
-                close(FD(evsel, cpu, 0));
-                FD(evsel, cpu, 0) = -1;
-        }
+        do {
+                while (--thread >= 0) {
+                        close(FD(evsel, cpu, thread));
+                        FD(evsel, cpu, thread) = -1;
+                }
+                thread = threads->nr;
+        } while (--cpu >= 0);
         return -1;
 }
 
-int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+static struct {
+        struct cpu_map map;
+        int cpus[1];
+} empty_cpu_map = {
+        .map.nr = 1,
+        .cpus   = { -1, },
+};
+
+static struct {
+        struct thread_map map;
+        int threads[1];
+} empty_thread_map = {
+        .map.nr  = 1,
+        .threads = { -1, },
+};
+
+int perf_evsel__open(struct perf_evsel *evsel,
+                     struct cpu_map *cpus, struct thread_map *threads)
 {
-        int thread;
-
-        if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, 1, threads->nr))
-                return -1;
 
-        for (thread = 0; thread < threads->nr; thread++) {
-                FD(evsel, 0, thread) = sys_perf_event_open(&evsel->attr,
-                                                           threads->map[thread], -1, -1, 0);
-                if (FD(evsel, 0, thread) < 0)
-                        goto out_close;
+        if (cpus == NULL) {
+                /* Work around old compiler warnings about strict aliasing */
+                cpus = &empty_cpu_map.map;
         }
 
-        return 0;
+        if (threads == NULL)
+                threads = &empty_thread_map.map;
 
-out_close:
-        while (--thread >= 0) {
-                close(FD(evsel, 0, thread));
-                FD(evsel, 0, thread) = -1;
-        }
-        return -1;
+        return __perf_evsel__open(evsel, cpus, threads);
 }
 
-int perf_evsel__open(struct perf_evsel *evsel, 
-                     struct cpu_map *cpus, struct thread_map *threads)
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
 {
-        if (threads == NULL)
-                return perf_evsel__open_per_cpu(evsel, cpus);
+        return __perf_evsel__open(evsel, cpus, &empty_thread_map.map);
+}
 
-        return perf_evsel__open_per_thread(evsel, threads);
+int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+{
+        return __perf_evsel__open(evsel, &empty_cpu_map.map, threads);
 }