[PATCH RFC v3 6/6] perf tools: Use extended syscall error reporting

[Alexander Shishkin <alexander.shishkin@linux.intel.com>]

If the kernel has an extended error report for us, use it instead of
trying to guess what might have gone wrong.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 tools/perf/util/evsel.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index c53f79123b..1804781072 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -27,6 +27,7 @@
 #include "debug.h"
 #include "trace-event.h"
 #include "stat.h"
+#include "exterr.h"
 
 static struct {
 	bool sample_id_all;
@@ -2266,7 +2267,16 @@ bool perf_evsel__fallback(struct perf_evsel *evsel, int err,
 int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
 			      int err, char *msg, size_t size)
 {
-	char sbuf[STRERR_BUFSIZE];
+	char sbuf[BUFSIZ];
+	int ret;
+
+	ret = exterr__strerror(msg, size);
+	/*
+	 * If kernel gave an extended error description, don't try to be any
+	 * more helpful here.
+	 */
+	if (ret > 0)
+		return ret;
 
 	switch (err) {
 	case EPERM:
-- 
2.5.1