cgroup: make cgroup_task_iter remember the cgroup being iterated

Currently all cgroup_task_iter functions require @cgrp to be passed
in, which is superflous and increases chance of usage error.  Make
cgroup_task_iter remember the cgroup being iterated and drop @cgrp
argument from next and end functions.

This patch doesn't introduce any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 00b055dd1d3d..5a5f4dc649f0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1804,7 +1804,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
                 struct task_struct *task;
 
                 cgroup_task_iter_start(cgroup, &it);
-                while ((task = cgroup_task_iter_next(cgroup, &it))) {
+                while ((task = cgroup_task_iter_next(&it))) {
                         switch (oom_scan_process_thread(task, totalpages, NULL,
                                                         false)) {
                         case OOM_SCAN_SELECT:
@@ -1817,7 +1817,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
                         case OOM_SCAN_CONTINUE:
                                 continue;
                         case OOM_SCAN_ABORT:
-                                cgroup_task_iter_end(cgroup, &it);
+                                cgroup_task_iter_end(&it);
                                 mem_cgroup_iter_break(memcg, iter);
                                 if (chosen)
                                         put_task_struct(chosen);
@@ -1834,7 +1834,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
                                 get_task_struct(chosen);
                         }
                 }
-                cgroup_task_iter_end(cgroup, &it);
+                cgroup_task_iter_end(&it);
         }
 
         if (!chosen)