selftests/resctrl: Refactor feature check to use resource and feature name

Feature check in validate_resctrl_feature_request() takes in the test
name string and maps that to what to check per test.

Pass resource and feature names to validate_resctrl_feature_request()
directly rather than deriving them from the test name inside the
function which makes the feature check easier to extend for new test
cases.

Use !! in the return statement to make the boolean conversion more
obvious even if it is not strictly necessary from correctness point of
view (to avoid it looking like the function is returning a freed
pointer).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Cc: <stable@vger.kernel.org> # selftests/resctrl: Remove duplicate feature check from CMT test
Cc: <stable@vger.kernel.org> # selftests/resctrl: Move _GNU_SOURCE define into Makefile
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 27 insertions, 42 deletions

diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index bd36ee206602..3a8111362d26 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -8,6 +8,8 @@
  *    Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
  *    Fenghua Yu <fenghua.yu@intel.com>
  */
+#include <limits.h>
+
 #include "resctrl.h"
 
 static int find_resctrl_mount(char *buffer)
@@ -604,63 +606,46 @@ char *fgrep(FILE *inf, const char *str)
 
 /*
  * validate_resctrl_feature_request - Check if requested feature is valid.
- * @resctrl_val:	Requested feature
+ * @resource:	Required resource (e.g., MB, L3, L2, L3_MON, etc.)
+ * @feature:	Required monitor feature (in mon_features file). Can only be
+ *		set for L3_MON. Must be NULL for all other resources.
  *
- * Return: True if the feature is supported, else false. False is also
- *         returned if resctrl FS is not mounted.
+ * Return: True if the resource/feature is supported, else false. False is
+ *         also returned if resctrl FS is not mounted.
  */
-bool validate_resctrl_feature_request(const char *resctrl_val)
+bool validate_resctrl_feature_request(const char *resource, const char *feature)
 {
+	char res_path[PATH_MAX];
 	struct stat statbuf;
-	bool found = false;
 	char *res;
 	FILE *inf;
 	int ret;
 
-	if (!resctrl_val)
+	if (!resource)
 		return false;
 
 	ret = find_resctrl_mount(NULL);
 	if (ret)
 		return false;
 
-	if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {
-		if (!stat(L3_PATH, &statbuf))
-			return true;
-	} else if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
-		if (!stat(MB_PATH, &statbuf))
-			return true;
-	} else if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
-		   !strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) {
-		if (!stat(L3_MON_PATH, &statbuf)) {
-			inf = fopen(L3_MON_FEATURES_PATH, "r");
-			if (!inf)
-				return false;
-
-			if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) {
-				res = fgrep(inf, "llc_occupancy");
-				if (res) {
-					found = true;
-					free(res);
-				}
-			}
-
-			if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) {
-				res = fgrep(inf, "mbm_total_bytes");
-				if (res) {
-					free(res);
-					res = fgrep(inf, "mbm_local_bytes");
-					if (res) {
-						found = true;
-						free(res);
-					}
-				}
-			}
-			fclose(inf);
-		}
-	}
+	snprintf(res_path, sizeof(res_path), "%s/%s", INFO_PATH, resource);
+
+	if (stat(res_path, &statbuf))
+		return false;
+
+	if (!feature)
+		return true;
+
+	snprintf(res_path, sizeof(res_path), "%s/%s/mon_features", INFO_PATH, resource);
+	inf = fopen(res_path, "r");
+	if (!inf)
+		return false;
+
+	res = fgrep(inf, feature);
+	free(res);
+	fclose(inf);
 
-	return found;
+	return !!res;
 }
 
 int filter_dmesg(void)