cgroup: make cgroup_taskset deal with cgroup_subsys_state instead of cgroup

cgroup is in the process of converting to css (cgroup_subsys_state)
from cgroup as the principal subsystem interface handle.  This is
mostly to prepare for the unified hierarchy support where css's will
be created and destroyed dynamically but also helps cleaning up
subsystem implementations as css is usually what they are interested
in anyway.

cgroup_taskset which is used by the subsystem attach methods is the
last cgroup subsystem API which isn't using css as the handle.  Update
cgroup_taskset_cur_cgroup() to cgroup_taskset_cur_css() and
cgroup_taskset_for_each() to take @skip_css instead of @skip_cgrp.

The conversions are pretty mechanical.  One exception is
cpuset::cgroup_cs(), which lost its last user and got removed.

This patch shouldn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index b065d24486e6..d9a970568be9 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -562,20 +562,22 @@ int cgroup_task_count(const struct cgroup *cgrp);
 struct cgroup_taskset;
 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
-struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset);
+struct cgroup_subsys_state *cgroup_taskset_cur_css(struct cgroup_taskset *tset,
+                                                   int subsys_id);
 int cgroup_taskset_size(struct cgroup_taskset *tset);
 
 /**
  * cgroup_taskset_for_each - iterate cgroup_taskset
  * @task: the loop cursor
- * @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all
+ * @skip_css: skip if task's css matches this, %NULL to iterate through all
  * @tset: taskset to iterate
  */
-#define cgroup_taskset_for_each(task, skip_cgrp, tset)                  \
+#define cgroup_taskset_for_each(task, skip_css, tset)                   \
         for ((task) = cgroup_taskset_first((tset)); (task);             \
              (task) = cgroup_taskset_next((tset)))                      \
-                if (!(skip_cgrp) ||                                     \
-                    cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp))
+                if (!(skip_css) ||                                      \
+                    cgroup_taskset_cur_css((tset),                      \
+                        (skip_css)->ss->subsys_id) != (skip_css))
 
 /*
  * Control Group subsystem type.