selftests/resctrl: Allow ->setup() to return errors

resctrl_val() assumes ->setup() always returns either 0 to continue
tests or < 0 in case of the normal termination of tests after x runs.
The latter overlaps with normal error returns.

Define END_OF_TESTS (=1) to differentiate the normal termination of
tests and return errors as negative values. Alter callers of ->setup()
to handle errors properly.

Fixes: 790bf585 ("selftests/resctrl: Add Cache Allocation Technology (CAT) selftest")
Fixes: ecdbb911 ("selftests/resctrl: Add MBM test")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/resctrl/cache.c

@@ -244,10 +244,12 @@ int cat_val(struct resctrl_val_param *param)
 	while (1) {
 		if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {
 			ret = param->setup(1, param);
-			if (ret) {
+			if (ret == END_OF_TESTS) {
 				ret = 0;
 				break;
 			}
+			if (ret < 0)
+				break;
 			ret = reset_enable_llc_perf(bm_pid, param->cpu_no);
 			if (ret)
 				break;

tools/testing/selftests/resctrl/cat_test.c

@@ -40,7 +40,7 @@ static int cat_setup(int num, ...)
 
 	/* Run NUM_OF_RUNS times */
 	if (p->num_of_runs >= NUM_OF_RUNS)
-		return -1;
+		return END_OF_TESTS;
 
 	if (p->num_of_runs == 0) {
 		sprintf(schemata, "%lx", p->mask);

tools/testing/selftests/resctrl/cmt_test.c

@@ -32,7 +32,7 @@ static int cmt_setup(int num, ...)
 
 	/* Run NUM_OF_RUNS times */
 	if (p->num_of_runs >= NUM_OF_RUNS)
-		return -1;
+		return END_OF_TESTS;
 
 	p->num_of_runs++;
 

tools/testing/selftests/resctrl/mba_test.c

@@ -41,7 +41,7 @@ static int mba_setup(int num, ...)
 		return 0;
 
 	if (allocation < ALLOCATION_MIN || allocation > ALLOCATION_MAX)
-		return -1;
+		return END_OF_TESTS;
 
 	sprintf(allocation_str, "%d", allocation);
 

tools/testing/selftests/resctrl/mbm_test.c

@@ -95,7 +95,7 @@ static int mbm_setup(int num, ...)
 
 	/* Run NUM_OF_RUNS times */
 	if (num_of_runs++ >= NUM_OF_RUNS)
-		return -1;
+		return END_OF_TESTS;
 
 	va_start(param, num);
 	p = va_arg(param, struct resctrl_val_param *);

tools/testing/selftests/resctrl/resctrl.h

@@ -37,6 +37,8 @@
 #define ARCH_INTEL     1
 #define ARCH_AMD       2
 
+#define END_OF_TESTS	1
+
 #define PARENT_EXIT(err_msg)			\
 	do {					\
 		perror(err_msg);		\

tools/testing/selftests/resctrl/resctrl_val.c

@@ -735,10 +735,12 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
 	/* Test runs until the callback setup() tells the test to stop. */
 	while (1) {
 		ret = param->setup(1, param);
-		if (ret) {
+		if (ret == END_OF_TESTS) {
 			ret = 0;
 			break;
 		}
+		if (ret < 0)
+			break;
 
 		if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
 		    !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {