[PATCH 4/5] perf tools: Propagate error info from tp_format

[Jiri Olsa <jolsa@kernel.org>]

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.

Link: http://lkml.kernel.org/n/tip-bzdckgv1zfp2y8up9l7ojt7y@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/builtin-trace.c                  | 19 +++++++++++--------
 tools/perf/tests/evsel-tp-sched.c           | 10 ++++++++--
 tools/perf/tests/openat-syscall-all-cpus.c  |  3 ++-
 tools/perf/tests/openat-syscall-tp-fields.c |  3 ++-
 tools/perf/tests/openat-syscall.c           |  3 ++-
 tools/perf/util/evlist.c                    |  3 ++-
 tools/perf/util/evsel.c                     | 11 +++++++++--
 tools/perf/util/evsel.h                     |  3 +++
 tools/perf/util/parse-events.c              |  6 +++---
 tools/perf/util/trace-event.c               | 13 +++++++++++--
 10 files changed, 53 insertions(+), 21 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) {
diff --git a/tools/perf/tests/evsel-tp-sched.c b/tools/perf/tests/evsel-tp-sched.c
index 52162425c969..790e413d9a1f 100644
--- a/tools/perf/tests/evsel-tp-sched.c
+++ b/tools/perf/tests/evsel-tp-sched.c
@@ -1,3 +1,4 @@
+#include <linux/err.h>
 #include <traceevent/event-parse.h>
 #include "evsel.h"
 #include "tests.h"
@@ -36,8 +37,8 @@ int test__perf_evsel__tp_sched_test(void)
 	struct perf_evsel *evsel = perf_evsel__newtp("sched", "sched_switch");
 	int ret = 0;
 
-	if (evsel == NULL) {
-		pr_debug("perf_evsel__new\n");
+	if (IS_ERR(evsel)) {
+		pr_debug("perf_evsel__newtp failed with %ld\n", PTR_ERR(evsel));
 		return -1;
 	}
 
@@ -66,6 +67,11 @@ int test__perf_evsel__tp_sched_test(void)
 
 	evsel = perf_evsel__newtp("sched", "sched_wakeup");
 
+	if (IS_ERR(evsel)) {
+		pr_debug("perf_evsel__newtp failed with %ld\n", PTR_ERR(evsel));
+		return -1;
+	}
+
 	if (perf_evsel__test_field(evsel, "comm", 16, true))
 		ret = -1;
 
diff --git a/tools/perf/tests/openat-syscall-all-cpus.c b/tools/perf/tests/openat-syscall-all-cpus.c
index 495d8126b722..9e104a2e973d 100644
--- a/tools/perf/tests/openat-syscall-all-cpus.c
+++ b/tools/perf/tests/openat-syscall-all-cpus.c
@@ -1,4 +1,5 @@
 #include <api/fs/fs.h>
+#include <linux/err.h>
 #include "evsel.h"
 #include "tests.h"
 #include "thread_map.h"
@@ -31,7 +32,7 @@ int test__openat_syscall_event_on_all_cpus(void)
 	CPU_ZERO(&cpu_set);
 
 	evsel = perf_evsel__newtp("syscalls", "sys_enter_openat");
-	if (evsel == NULL) {
+	if (IS_ERR(evsel)) {
 		tracing_path__strerror_open_tp(errno, errbuf, sizeof(errbuf), "syscalls", "sys_enter_openat");
 		pr_err("%s\n", errbuf);
 		goto out_thread_map_delete;
diff --git a/tools/perf/tests/openat-syscall-tp-fields.c b/tools/perf/tests/openat-syscall-tp-fields.c
index 01a19626c846..473d3869727e 100644
--- a/tools/perf/tests/openat-syscall-tp-fields.c
+++ b/tools/perf/tests/openat-syscall-tp-fields.c
@@ -1,3 +1,4 @@
+#include <linux/err.h>
 #include "perf.h"
 #include "evlist.h"
 #include "evsel.h"
@@ -30,7 +31,7 @@ int test__syscall_openat_tp_fields(void)
 	}
 
 	evsel = perf_evsel__newtp("syscalls", "sys_enter_openat");
-	if (evsel == NULL) {
+	if (IS_ERR(evsel)) {
 		pr_debug("%s: perf_evsel__newtp\n", __func__);
 		goto out_delete_evlist;
 	}
diff --git a/tools/perf/tests/openat-syscall.c b/tools/perf/tests/openat-syscall.c
index 08ac9d94a050..7b1db8306098 100644
--- a/tools/perf/tests/openat-syscall.c
+++ b/tools/perf/tests/openat-syscall.c
@@ -1,4 +1,5 @@
 #include <api/fs/tracing_path.h>
+#include <linux/err.h>
 #include "thread_map.h"
 #include "evsel.h"
 #include "debug.h"
@@ -19,7 +20,7 @@ int test__openat_syscall_event(void)
 	}
 
 	evsel = perf_evsel__newtp("syscalls", "sys_enter_openat");
-	if (evsel == NULL) {
+	if (IS_ERR(evsel)) {
 		tracing_path__strerror_open_tp(errno, errbuf, sizeof(errbuf), "syscalls", "sys_enter_openat");
 		pr_err("%s\n", errbuf);
 		goto out_thread_map_delete;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index d51a5200c8af..3cb2bf9bd4bd 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -25,6 +25,7 @@
 #include <linux/bitops.h>
 #include <linux/hash.h>
 #include <linux/log2.h>
+#include <linux/err.h>
 
 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
 static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx);
@@ -265,7 +266,7 @@ int perf_evlist__add_newtp(struct perf_evlist *evlist,
 {
 	struct perf_evsel *evsel = perf_evsel__newtp(sys, name);
 
-	if (evsel == NULL)
+	if (IS_ERR(evsel))
 		return -1;
 
 	evsel->handler = handler;
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 771ade4d5966..08c20ee4e27d 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -13,6 +13,7 @@
 #include <traceevent/event-parse.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/perf_event.h>
+#include <linux/err.h>
 #include <sys/resource.h>
 #include "asm/bug.h"
 #include "callchain.h"
@@ -225,9 +226,13 @@ struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)
 	return evsel;
 }
 
+/*
+ * Returns pointer with encoded error via <linux/err.h> interface.
+ */
 struct perf_evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int idx)
 {
 	struct perf_evsel *evsel = zalloc(perf_evsel__object.size);
+	int err = -ENOMEM;
 
 	if (evsel != NULL) {
 		struct perf_event_attr attr = {
@@ -240,8 +245,10 @@ struct perf_evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int
 			goto out_free;
 
 		evsel->tp_format = trace_event__tp_format(sys, name);
-		if (evsel->tp_format == NULL)
+		if (IS_ERR(evsel->tp_format)) {
+			err = PTR_ERR(evsel->tp_format);
 			goto out_free;
+		}
 
 		event_attr_init(&attr);
 		attr.config = evsel->tp_format->id;
@@ -254,7 +261,7 @@ struct perf_evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int
 out_free:
 	zfree(&evsel->name);
 	free(evsel);
-	return NULL;
+	return ERR_PTR(err);
 }
 
 const char *perf_evsel__hw_names[PERF_COUNT_HW_MAX] = {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 298e6bbca200..b6e8ff876f17 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -161,6 +161,9 @@ static inline struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
 
 struct perf_evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int idx);
 
+/*
+ * Returns pointer with encoded error via <linux/err.h> interface.
+ */
 static inline struct perf_evsel *perf_evsel__newtp(const char *sys, const char *name)
 {
 	return perf_evsel__newtp_idx(sys, name, 0);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 1b284b8ad243..c47831c47220 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1,4 +1,5 @@
 #include <linux/hw_breakpoint.h>
+#include <linux/err.h>
 #include "util.h"
 #include "../perf.h"
 #include "evlist.h"
@@ -393,11 +394,10 @@ static int add_tracepoint(struct list_head *list, int *idx,
 	struct perf_evsel *evsel;
 
 	evsel = perf_evsel__newtp_idx(sys_name, evt_name, (*idx)++);
-	if (!evsel)
-		return -ENOMEM;
+	if (IS_ERR(evsel))
+		return PTR_ERR(evsel);
 
 	list_add_tail(&evsel->node, list);
-
 	return 0;
 }
 
diff --git a/tools/perf/util/trace-event.c b/tools/perf/util/trace-event.c
index 2f4996ab313d..8e3a60e3e15f 100644
--- a/tools/perf/util/trace-event.c
+++ b/tools/perf/util/trace-event.c
@@ -7,6 +7,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <linux/kernel.h>
+#include <linux/err.h>
 #include <traceevent/event-parse.h>
 #include <api/fs/tracing_path.h>
 #include "trace-event.h"
@@ -66,6 +67,9 @@ void trace_event__cleanup(struct trace_event *t)
 	pevent_free(t->pevent);
 }
 
+/*
+ * Returns pointer with encoded error via <linux/err.h> interface.
+ */
 static struct event_format*
 tp_format(const char *sys, const char *name)
 {
@@ -74,12 +78,14 @@ tp_format(const char *sys, const char *name)
 	char path[PATH_MAX];
 	size_t size;
 	char *data;
+	int err;
 
 	scnprintf(path, PATH_MAX, "%s/%s/%s/format",
 		  tracing_events_path, sys, name);
 
-	if (filename__read_str(path, &data, &size))
-		return NULL;
+	err = filename__read_str(path, &data, &size);
+	if (err)
+		return ERR_PTR(err);
 
 	pevent_parse_format(pevent, &event, data, size, sys);
 
@@ -87,6 +93,9 @@ tp_format(const char *sys, const char *name)
 	return event;
 }
 
+/*
+ * Returns pointer with encoded error via <linux/err.h> interface.
+ */
 struct event_format*
 trace_event__tp_format(const char *sys, const char *name)
 {
-- 
2.4.3