selftests/resctrl: Move resctrl FS mount/umount to higher level

A few places currently lack umounting resctrl FS on error paths:
  - cmt_resctrl_val() has multiple error paths with direct return.
  - cat_perf_miss_val() has multiple error paths with direct return.
In addition, validate_resctrl_feature_request() is called by
run_mbm_test() and run_mba_test(). Neither MBA nor MBM test tries to
umount resctrl FS.

Each and every test does require resctrl FS to be present already for
feature check. Thus, it makes sense to just mount it on higher level in
resctrl_tests.c and properly pair it with umount.

Move resctrl FS (re)mount/unmount into each test function in
resctrl_tests.c. Make feature validation to simply check that resctrl
FS is mounted.

As there's the final umount in main() before this change, the selftest
should not leave resctrl FS behind after the tests even if one of the
forementioned paths is taken (thus, no fixes tag).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan (Fujitsu) <tan.shaopeng@fujitsu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

5 files changed, 46 insertions, 23 deletions

diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index fb1443f888c4..e1c071dec1b0 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -106,10 +106,6 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 
 	cache_size = 0;
 
-	ret = remount_resctrlfs(true);
-	if (ret)
-		return ret;
-
 	/* Get default cbm mask for L3/L2 cache */
 	ret = get_cbm_mask(cache_type, cbm_mask);
 	if (ret)
@@ -227,8 +223,6 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 
 out:
 	cat_test_cleanup();
-	if (bm_pid)
-		umount_resctrlfs();
 
 	return ret;
 }
diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index af71b2141271..426d11189a99 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_test.c
@@ -86,10 +86,6 @@ int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
 
 	cache_size = 0;
 
-	ret = remount_resctrlfs(true);
-	if (ret)
-		return ret;
-
 	if (!validate_resctrl_feature_request(CMT_STR))
 		return -1;
 
diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
index 61c3882a26c8..6bf4ead74496 100644
--- a/tools/testing/selftests/resctrl/resctrl_tests.c
+++ b/tools/testing/selftests/resctrl/resctrl_tests.c
@@ -77,9 +77,15 @@ static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
 
 	ksft_print_msg("Starting MBM BW change ...\n");
 
+	res = remount_resctrlfs(true);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(MBM_STR) || (get_vendor() != ARCH_INTEL)) {
 		ksft_test_result_skip("Hardware does not support MBM or MBM is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
@@ -88,6 +94,9 @@ static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
 	ksft_test_result(!res, "MBM: bw change\n");
 	if ((get_vendor() == ARCH_INTEL) && res)
 		ksft_print_msg("Intel MBM may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_mba_test(bool has_ben, char **benchmark_cmd, int span,
@@ -97,15 +106,24 @@ static void run_mba_test(bool has_ben, char **benchmark_cmd, int span,
 
 	ksft_print_msg("Starting MBA Schemata change ...\n");
 
+	res = remount_resctrlfs(true);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(MBA_STR) || (get_vendor() != ARCH_INTEL)) {
 		ksft_test_result_skip("Hardware does not support MBA or MBA is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
 		sprintf(benchmark_cmd[1], "%d", span);
 	res = mba_schemata_change(cpu_no, bw_report, benchmark_cmd);
 	ksft_test_result(!res, "MBA: schemata change\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
@@ -113,9 +131,16 @@ static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
 	int res;
 
 	ksft_print_msg("Starting CMT test ...\n");
+
+	res = remount_resctrlfs(true);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(CMT_STR)) {
 		ksft_test_result_skip("Hardware does not support CMT or CMT is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
@@ -124,6 +149,9 @@ static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
 	ksft_test_result(!res, "CMT: test\n");
 	if ((get_vendor() == ARCH_INTEL) && res)
 		ksft_print_msg("Intel CMT may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_cat_test(int cpu_no, int no_of_bits)
@@ -132,13 +160,22 @@ static void run_cat_test(int cpu_no, int no_of_bits)
 
 	ksft_print_msg("Starting CAT test ...\n");
 
+	res = remount_resctrlfs(true);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(CAT_STR)) {
 		ksft_test_result_skip("Hardware does not support CAT or CAT is disabled\n");
-		return;
+		goto umount;
 	}
 
 	res = cat_perf_miss_val(cpu_no, no_of_bits, "L3");
 	ksft_test_result(!res, "CAT: test\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 int main(int argc, char **argv)
@@ -269,7 +306,5 @@ int main(int argc, char **argv)
 	if (cat_test)
 		run_cat_test(cpu_no, no_of_bits);
 
-	umount_resctrlfs();
-
 	ksft_finished();
 }
diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
index ab1eab1e7ff6..e8f1e6a59f4a 100644
--- a/tools/testing/selftests/resctrl/resctrl_val.c
+++ b/tools/testing/selftests/resctrl/resctrl_val.c
@@ -648,10 +648,6 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
 			return ret;
 	}
 
-	ret = remount_resctrlfs(param->mum_resctrlfs);
-	if (ret)
-		return ret;
-
 	/*
 	 * If benchmark wasn't successfully started by child, then child should
 	 * kill parent, so save parent's pid
@@ -788,7 +784,6 @@ unregister:
 	signal_handler_unregister();
 out:
 	kill(bm_pid, SIGKILL);
-	umount_resctrlfs();
 
 	return ret;
 }
diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index cf0c8dd34b8b..edc3f92b11b1 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -617,7 +617,8 @@ char *fgrep(FILE *inf, const char *str)
  * validate_resctrl_feature_request - Check if requested feature is valid.
  * @resctrl_val:	Requested feature
  *
- * Return: True if the feature is supported, else false
+ * Return: True if the feature is supported, else false. False is also
+ *         returned if resctrl FS is not mounted.
  */
 bool validate_resctrl_feature_request(const char *resctrl_val)
 {
@@ -625,11 +626,13 @@ bool validate_resctrl_feature_request(const char *resctrl_val)
 	bool found = false;
 	char *res;
 	FILE *inf;
+	int ret;
 
 	if (!resctrl_val)
 		return false;
 
-	if (remount_resctrlfs(false))
+	ret = find_resctrl_mount(NULL);
+	if (ret)
 		return false;
 
 	if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {