perf tools: Dont stop PMU parsing on alias parse error

commit 940db6dcd3f4659303fdf6befe7416adc4d24118 upstream.

When an error happens during alias parsing currently the complete
parsing of all attributes of the PMU is stopped. This is breaks old perf
on a newer kernel that may have not-yet-know alias attributes (such as
.scale or .per-pkg).

Continue when some attribute is unparseable.

This is IMHO a stable candidate and should be backported to older
versions to avoid problems with newer kernels.

v2: Print warnings when something goes wrong.
v3: Change warning to debug output

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1455749095-18358-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 0400c46c5815d8246eaeca5329e4edf3019a7d7c..17bd6049feaf0705a1fd6a2058ae864017941d54 100644 (file)
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -217,13 +217,12 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
        struct dirent *evt_ent;
        DIR *event_dir;
        size_t len;
-       int ret = 0;
 
        event_dir = opendir(dir);
        if (!event_dir)
                return -EINVAL;
 
-       while (!ret && (evt_ent = readdir(event_dir))) {
+       while ((evt_ent = readdir(event_dir))) {
                char path[PATH_MAX];
                char *name = evt_ent->d_name;
                FILE *file;
@@ -243,17 +242,19 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 
                snprintf(path, PATH_MAX, "%s/%s", dir, name);
 
-               ret = -EINVAL;
                file = fopen(path, "r");
-               if (!file)
-                       break;
+               if (!file) {
+                       pr_debug("Cannot open %s\n", path);
+                       continue;
+               }
 
-               ret = perf_pmu__new_alias(head, dir, name, file);
+               if (perf_pmu__new_alias(head, dir, name, file) < 0)
+                       pr_debug("Cannot set up %s\n", name);
                fclose(file);
        }
 
        closedir(event_dir);
-       return ret;
+       return 0;
 }
 
 /*