perf evsel: Propagate error info from tp_format

Propagate error info from tp_format via ERR_PTR to get it all the way
down to the parse-event.c tracepoint adding routines. Following
functions now return pointer with encoded error:

  - tp_format
  - trace_event__tp_format
  - perf_evsel__newtp_idx
  - perf_evsel__newtp

This affects several other places in perf, that cannot use pointer check
anymore, but must utilize the err.h interface, when getting error
information from above functions list.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Link: http://lkml.kernel.org/r/1441615087-13886-5-git-send-email-jolsa@kernel.org
[ Add two missing ERR_PTR() and one IS_ERR() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 215653274102..93b80f12f35e 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -38,6 +38,7 @@
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <linux/futex.h>
+#include <linux/err.h>
 
 /* For older distros: */
 #ifndef MAP_STACK
@@ -245,13 +246,14 @@ static struct perf_evsel *perf_evsel__syscall_newtp(const char *direction, void
         struct perf_evsel *evsel = perf_evsel__newtp("raw_syscalls", direction);
 
         /* older kernel (e.g., RHEL6) use syscalls:{enter,exit} */
-        if (evsel == NULL)
+        if (IS_ERR(evsel))
                 evsel = perf_evsel__newtp("syscalls", direction);
 
-        if (evsel) {
-                if (perf_evsel__init_syscall_tp(evsel, handler))
-                        goto out_delete;
-        }
+        if (IS_ERR(evsel))
+                return NULL;
+
+        if (perf_evsel__init_syscall_tp(evsel, handler))
+                goto out_delete;
 
         return evsel;
 
@@ -1705,12 +1707,12 @@ static int trace__read_syscall_info(struct trace *trace, int id)
         snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->name);
         sc->tp_format = trace_event__tp_format("syscalls", tp_name);
 
-        if (sc->tp_format == NULL && sc->fmt && sc->fmt->alias) {
+        if (IS_ERR(sc->tp_format) && sc->fmt && sc->fmt->alias) {
                 snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->fmt->alias);
                 sc->tp_format = trace_event__tp_format("syscalls", tp_name);
         }
 
-        if (sc->tp_format == NULL)
+        if (IS_ERR(sc->tp_format))
                 return -1;
 
         sc->args = sc->tp_format->format.fields;
@@ -2390,7 +2392,8 @@ static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp);
 static bool perf_evlist__add_vfs_getname(struct perf_evlist *evlist)
 {
         struct perf_evsel *evsel = perf_evsel__newtp("probe", "vfs_getname");
-        if (evsel == NULL)
+
+        if (IS_ERR(evsel))
                 return false;
 
         if (perf_evsel__field(evsel, "pathname") == NULL) {