From 6ef81c55a2b6584cb642917f5fdf3632ef44b670 Mon Sep 17 00:00:00 2001
From: Mamatha Inamdar <mamatha4@linux.vnet.ibm.com>
Date: Thu, 22 Aug 2019 12:50:49 +0530
Subject: 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>
---
 tools/perf/builtin-diff.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

(limited to 'tools/perf/builtin-diff.c')

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 827e4800d862..c37a78677955 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -23,6 +23,7 @@
 #include "util/time-utils.h"
 #include "util/annotate.h"
 #include "util/map.h"
+#include <linux/err.h>
 #include <linux/zalloc.h>
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
@@ -1153,9 +1154,9 @@ static int check_file_brstack(void)
 
 	data__for_each_file(i, d) {
 		d->session = perf_session__new(&d->data, false, &pdiff.tool);
-		if (!d->session) {
+		if (IS_ERR(d->session)) {
 			pr_err("Failed to open %s\n", d->data.path);
-			return -1;
+			return PTR_ERR(d->session);
 		}
 
 		has_br_stack = perf_header__has_feat(&d->session->header,
@@ -1185,9 +1186,9 @@ static int __cmd_diff(void)
 
 	data__for_each_file(i, d) {
 		d->session = perf_session__new(&d->data, false, &pdiff.tool);
-		if (!d->session) {
+		if (IS_ERR(d->session)) {
+			ret = PTR_ERR(d->session);
 			pr_err("Failed to open %s\n", d->data.path);
-			ret = -1;
 			goto out_delete;
 		}
 
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