cgroup: reorder cgroup_migrate()'s parameters

cgroup_migrate() has the destination cgroup as the first parameter
while cgroup_task_migrate() has the destination cset as the last.
Another migration function is scheduled to be added which can make the
discrepancy further stand out.  Let's reorder cgroup_migrate()'s
parameters so that the destination cgroup is the last.

This doesn't cause any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7f4b85a..dc07956 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2362,9 +2362,9 @@ err:
 
 /**
  * cgroup_migrate - migrate a process or task to a cgroup
- * @cgrp: the destination cgroup
  * @leader: the leader of the process or the task to migrate
  * @threadgroup: whether @leader points to the whole process or a single task
+ * @cgrp: the destination cgroup
  *
  * Migrate a process or task denoted by @leader to @cgrp.  If migrating a
  * process, the caller must be holding cgroup_threadgroup_rwsem.  The
@@ -2378,8 +2378,8 @@ err:
  * decided for all targets by invoking group_migrate_prepare_dst() before
  * actually starting migrating.
  */
-static int cgroup_migrate(struct cgroup *cgrp, struct task_struct *leader,
-                         bool threadgroup)
+static int cgroup_migrate(struct task_struct *leader, bool threadgroup,
+                         struct cgroup *cgrp)
 {
        struct cgroup_taskset tset = {
                .src_csets      = LIST_HEAD_INIT(tset.src_csets),
@@ -2516,7 +2516,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp,
        /* prepare dst csets and commit */
        ret = cgroup_migrate_prepare_dst(dst_cgrp, &preloaded_csets);
        if (!ret)
-               ret = cgroup_migrate(dst_cgrp, leader, threadgroup);
+               ret = cgroup_migrate(leader, threadgroup, dst_cgrp);
 
        cgroup_migrate_finish(&preloaded_csets);
        return ret;
@@ -2823,7 +2823,7 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)
                                goto out_finish;
                        last_task = task;
 
-                       ret = cgroup_migrate(src_cset->dfl_cgrp, task, true);
+                       ret = cgroup_migrate(task, true, src_cset->dfl_cgrp);
 
                        put_task_struct(task);
 
@@ -3905,7 +3905,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
                css_task_iter_end(&it);
 
                if (task) {
-                       ret = cgroup_migrate(to, task, false);
+                       ret = cgroup_migrate(task, false, to);
                        put_task_struct(task);
                }
        } while (task && !ret);