cpuset: Fix incorrect memory_pressure control file mapping

commit 1c08c22c upstream.

The memory_pressure control file was incorrectly set up without
a private value (0, by default). As a result, this control
file was treated like memory_migrate on read. By adding back the
FILE_MEMORY_PRESSURE private value, the correct memory pressure value
will be returned.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 7dbdb199 ("cgroup: replace cftype->mode with CFTYPE_WORLD_WRITABLE")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/cgroup/cpuset.c

@@ -1907,6 +1907,7 @@ static struct cftype files[] = {
 	{
 		.name = "memory_pressure",
 		.read_u64 = cpuset_read_u64,
+		.private = FILE_MEMORY_PRESSURE,
 	},
 
 	{