perf session: Return error code for perf_session__new() function on failure

This patch is to return error code of perf_new_session function on
failure instead of NULL.

Test Results:

Before Fix:

  $ perf c2c report -input
  failed to open nput: No such file or directory

  $ echo $?
  0
  $

After Fix:

  $ perf c2c report -input
  failed to open nput: No such file or directory

  $ echo $?
  254
  $

Committer notes:

Fix 'perf tests topology' case, where we use that TEST_ASSERT_VAL(...,
session), i.e. we need to pass zero in case of failure, which was the
case before when NULL was returned by perf_session__new() for failure,
but now we need to negate the result of IS_ERR(session) to respect that
TEST_ASSERT_VAL) expectation of zero meaning failure.

Reported-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>
Signed-off-by: Mamatha Inamdar <mamatha4@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shawn Landden <shawn@git.icu>
Cc: Song Liu <songliubraving@fb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Link: http://lore.kernel.org/lkml/20190822071223.17892.45782.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 15 insertions, 5 deletions

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index 0c268449959c..dbc772bfb04e 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -30,6 +30,7 @@
 #include "machine.h"
 #include "config.h"
 #include <linux/ctype.h>
+#include <linux/err.h>
 
 #define pr_N(n, fmt, ...) \
 	eprintf(n, debug_data_convert, fmt, ##__VA_ARGS__)
@@ -1619,8 +1620,10 @@ int bt_convert__perf2ctf(const char *input, const char *path,
 	err = -1;
 	/* perf.data session */
 	session = perf_session__new(&data, 0, &c.tool);
-	if (!session)
+	if (IS_ERR(session)) {
+		err = PTR_ERR(session);
 		goto free_writer;
+	}
 
 	if (c.queue_size) {
 		ordered_events__set_alloc_size(&session->ordered_events,
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 58b5bc34ba12..a621c73bad42 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -34,6 +34,7 @@
 #include "../perf.h"
 #include "arch/common.h"
 #include <internal/lib.h>
+#include <linux/err.h>
 
 #ifdef HAVE_ZSTD_SUPPORT
 static int perf_session__process_compressed_event(struct perf_session *session,
@@ -187,6 +188,7 @@ static int ordered_events__deliver_event(struct ordered_events *oe,
 struct perf_session *perf_session__new(struct perf_data *data,
 				       bool repipe, struct perf_tool *tool)
 {
+	int ret = -ENOMEM;
 	struct perf_session *session = zalloc(sizeof(*session));
 
 	if (!session)
@@ -201,13 +203,15 @@ struct perf_session *perf_session__new(struct perf_data *data,
 
 	perf_env__init(&session->header.env);
 	if (data) {
-		if (perf_data__open(data))
+		ret = perf_data__open(data);
+		if (ret < 0)
 			goto out_delete;
 
 		session->data = data;
 
 		if (perf_data__is_read(data)) {
-			if (perf_session__open(session) < 0)
+			ret = perf_session__open(session);
+			if (ret < 0)
 				goto out_delete;
 
 			/*
@@ -222,8 +226,11 @@ struct perf_session *perf_session__new(struct perf_data *data,
 			perf_evlist__init_trace_event_sample_raw(session->evlist);
 
 			/* Open the directory data. */
-			if (data->is_dir && perf_data__open_dir(data))
+			if (data->is_dir) {
+				ret = perf_data__open_dir(data);
+			if (ret)
 				goto out_delete;
+			}
 		}
 	} else  {
 		session->machines.host.env = &perf_env;
@@ -256,7 +263,7 @@ struct perf_session *perf_session__new(struct perf_data *data,
  out_delete:
 	perf_session__delete(session);
  out:
-	return NULL;
+	return ERR_PTR(ret);
 }
 
 static void perf_session__delete_threads(struct perf_session *session)