perf probe: Propagate error code when write(2) failed

When it failed to write probe commands to the probe_event file in
debugfs, it needs to propagate the error code properly.  Current code
blindly uses the return value of the write(2) so it always uses
-1 (-EPERM) and it might confuse users.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1420886028-15135-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7f9b8632e433..94a717bf007d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2052,9 +2052,11 @@ static int write_probe_trace_event(int fd, struct probe_trace_event *tev)
         pr_debug("Writing event: %s\n", buf);
         if (!probe_event_dry_run) {
                 ret = write(fd, buf, strlen(buf));
-                if (ret <= 0)
+                if (ret <= 0) {
+                        ret = -errno;
                         pr_warning("Failed to write event: %s\n",
                                    strerror_r(errno, sbuf, sizeof(sbuf)));
+                }
         }
         free(buf);
         return ret;