tunable: make use of save_restore

SAFE_ACCESS requires the pathname is exist otherwise TBROK.
so let's use TST_SR_TBROK in save_restore.

Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Li Wang <liwang@redhat.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>

testcases/kernel/mem/tunable/max_map_count.c

@@ -53,21 +53,6 @@
 #define MAP_COUNT_DEFAULT	1024
 #define MAX_MAP_COUNT		65536L
 
-static long old_max_map_count = -1;
-
-static void setup(void)
-{
-	SAFE_ACCESS(PATH_SYSVM "max_map_count", F_OK);
-
-	old_max_map_count = get_sys_tune("max_map_count");
-}
-
-static void cleanup(void)
-{
-	if (old_max_map_count != -1)
-		set_sys_tune("max_map_count", old_max_map_count, 0);
-}
-
 /* This is a filter to exclude map entries which aren't accounted
  * for in the vm_area_struct's map_count.
  */
@@ -205,11 +190,10 @@ static void max_map_count_test(void)
 static struct tst_test test = {
 	.needs_root = 1,
 	.forks_child = 1,
-	.setup = setup,
-	.cleanup = cleanup,
 	.test_all = max_map_count_test,
 	.save_restore = (const struct tst_path_val[]) {
 		{"/proc/sys/vm/overcommit_memory", "0", TST_SR_TBROK},
+		{"/proc/sys/vm/max_map_count", NULL, TST_SR_TBROK},
 		{}
 	},
 };

testcases/kernel/mem/tunable/min_free_kbytes.c

@@ -218,21 +218,15 @@ static void setup(void)
 	default_tune = get_sys_tune("min_free_kbytes");
 }
 
-static void cleanup(void)
-{
-	if (default_tune != -1)
-		set_sys_tune("min_free_kbytes", default_tune, 0);
-}
-
 static struct tst_test test = {
 	.needs_root = 1,
 	.forks_child = 1,
 	.max_runtime = TST_UNLIMITED_RUNTIME,
 	.setup = setup,
-	.cleanup = cleanup,
 	.test_all = min_free_kbytes_test,
 	.save_restore = (const struct tst_path_val[]) {
 		{"/proc/sys/vm/overcommit_memory", NULL, TST_SR_TBROK},
+		{"/proc/sys/vm/min_free_kbytes", NULL, TST_SR_TBROK},
 		{}
 	},
 };