[LTP] [PATCH v2] cgroup_fj_common.sh: Do not disable systemd related cgroup subsystems

[Ma Xinjian]

The cpu, io, memory, and pids subsystems under the root cgroup cannot be disabled
because they are used for systemd. Currently, the test of cpu and memory subsystems
in cgroup_fj_function.sh and cgroup_fj_stress.sh will report the error
"echo: write error: device or resource busy".

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Ma Xinjian <maxj.fnst@fujitsu.com>
---
 .../kernel/controllers/cgroup_fj/cgroup_fj_common.sh      | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/controllers/cgroup_fj/cgroup_fj_common.sh b/testcases/kernel/controllers/cgroup_fj/cgroup_fj_common.sh
index e866641ba..153d351d7 100755
--- a/testcases/kernel/controllers/cgroup_fj/cgroup_fj_common.sh
+++ b/testcases/kernel/controllers/cgroup_fj/cgroup_fj_common.sh
@@ -77,7 +77,13 @@ common_cleanup()
 
     cgroup_cleanup
 
-    [ "$cgroup_version" = "2" ] && ROD echo "-$subsystem" \> "/sys/fs/cgroup/cgroup.subtree_control"
+    if [ "$cgroup_version" = "2" ]; then
+        case "$subsystem" in
+        cpu|io|memory|pids)
+            :;;
+        *) ROD echo "-$subsystem" \> "/sys/fs/cgroup/cgroup.subtree_control";;
+        esac
+    fi
 }
 
 . cgroup_lib.sh
-- 
2.42.0