[PATCH v4 06/17] selftests/resctrl: Check for resctrl mount point only if resctrl FS is supported

From: Fenghua Yu <fenghua.yu@intel.com>
To: "Shuah Khan" <shuah@kernel.org>,
	"Tony Luck" <tony.luck@intel.com>,
	"Reinette Chatre" <reinette.chatre@intel.com>,
	"David Binderman" <dcb314@hotmail.com>,
	"Babu Moger" <babu.moger@amd.com>,
	"James Morse" <james.morse@arm.com>,
	"Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
	Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v4 06/17] selftests/resctrl: Check for resctrl mount point only if resctrl FS is supported
Date: Mon, 30 Nov 2020 20:19:59 +0000	[thread overview]
Message-ID: <20201130202010.178373-7-fenghua.yu@intel.com> (raw)
In-Reply-To: <20201130202010.178373-1-fenghua.yu@intel.com>

check_resctrlfs_support() does the following
1. Checks if the platform supports resctrl file system or not by looking
   for resctrl in /proc/filesystems
2. Calls opendir() on default resctrl file system path
   (i.e. /sys/fs/resctrl)
3. Checks if resctrl file system is mounted or not by looking at
   /proc/mounts

Steps 2 and 3 will fail if the platform does not support resctrl file
system. So, there is no need to check for them if step 1 fails.

Fix this by returning immediately if the platform does not support
resctrl file system.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 tools/testing/selftests/resctrl/resctrlfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index 2c574d143ff0..c676557b376d 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -579,6 +579,9 @@ bool check_resctrlfs_support(void)
 	printf("%sok kernel supports resctrl filesystem\n", ret ? "" : "not ");
 	tests_run++;
 
+	if (!ret)
+		return ret;
+
 	dp = opendir(RESCTRL_PATH);
 	printf("%sok resctrl mountpoint \"%s\" exists\n",
 	       dp ? "" : "not ", RESCTRL_PATH);
-- 
2.29.2

