selftests/resctrl: Fix set up schemata with 100% allocation on first run in MBM test

There is a comment "Set up shemata with 100% allocation on the first run"
in function mbm_setup(), but there is an increment bug and the condition
"num_of_runs == 0" will never be met and write_schemata() will never be
called to set schemata to 100%. Even if write_schemata() is called in MBM
test, since it is not supported for MBM test it does not set the schemata.
This is currently fine because resctrl_val_parm->mum_resctrlfs is always 1
and umount/mount will be run in each test to set the schemata to 100%.

To support the usage when MBM test does not unmount/remount resctrl
filesystem before the test starts, fix to call write_schemata() and
set schemata properly when the function is called for the first time.

Also, remove static local variable 'num_of_runs' because this is not
needed as there is resctrl_val_param->num_of_runs which should be used
instead like in cat_setup().

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
index c9dfa54af42f..9b591c35310f 100644
--- a/tools/testing/selftests/resctrl/mbm_test.c
+++ b/tools/testing/selftests/resctrl/mbm_test.c
@@ -89,23 +89,24 @@ static int check_results(int span)
 static int mbm_setup(int num, ...)
 {
 	struct resctrl_val_param *p;
-	static int num_of_runs;
 	va_list param;
 	int ret = 0;
 
-	/* Run NUM_OF_RUNS times */
-	if (num_of_runs++ >= NUM_OF_RUNS)
-		return END_OF_TESTS;
-
 	va_start(param, num);
 	p = va_arg(param, struct resctrl_val_param *);
 	va_end(param);
 
+	/* Run NUM_OF_RUNS times */
+	if (p->num_of_runs >= NUM_OF_RUNS)
+		return -1;
+
 	/* Set up shemata with 100% allocation on the first run. */
-	if (num_of_runs == 0)
+	if (p->num_of_runs == 0)
 		ret = write_schemata(p->ctrlgrp, "100", p->cpu_no,
 				     p->resctrl_val);
 
+	p->num_of_runs++;
+
 	return ret;
 }