selftests/mm: restore default nr_hugepages value during cleanup in hugetlb_reparenting_test.sh

During cleanup, the value of /proc/sys/vm/nr_hugepages is currently being
set to 0.  At the end of the test, if all tests pass, the original
nr_hugepages value is restored.  However, if any test fails, it remains
set to 0.

With this patch, we ensure that the original nr_hugepages value is
restored during cleanup, regardless of whether the test passes or fails.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 29750f71a9 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
Signed-off-by: Donet Tom <[email protected]>
Cc: Li Wang <[email protected]>
Cc: "Ritesh Harjani (IBM)" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Waiman Long <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

tools/testing/selftests/mm/hugetlb_reparenting_test.sh

@@ -56,7 +56,7 @@ function cleanup() {
   rmdir "$CGROUP_ROOT"/a/b 2>/dev/null
   rmdir "$CGROUP_ROOT"/a 2>/dev/null
   rmdir "$CGROUP_ROOT"/test1 2>/dev/null
-  echo 0 >/proc/sys/vm/nr_hugepages
+  echo $nr_hugepgs >/proc/sys/vm/nr_hugepages
   set -e
 }