cgroup: pass around cgroup_subsys_state instead of cgroup in file methods

cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup.
Please see the previous commit which converts the subsystem methods
for rationale.

This patch converts all cftype file operations to take @css instead of
@cgroup.  cftypes for the cgroup core files don't have their subsytem
pointer set.  These will automatically use the dummy_css added by the
previous patch and can be converted the same way.

Most subsystem conversions are straight forwards but there are some
interesting ones.

* freezer: update_if_frozen() is also converted to take @css instead
  of @cgroup for consistency.  This will make the code look simpler
  too once iterators are converted to use css.

* memory/vmpressure: mem_cgroup_from_css() needs to be exported to
  vmpressure while mem_cgroup_from_cont() can be made static.
  Updated accordingly.

* cpu: cgroup_tg() doesn't have any user left.  Removed.

* cpuacct: cgroup_ca() doesn't have any user left.  Removed.

* hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left.
  Removed.

* net_cls: cgrp_cls_state() doesn't have any user left.  Removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 5 insertions, 9 deletions

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index dc39838..8ea1184 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -28,11 +28,6 @@ static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state
 	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
 }
 
-static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
-{
-	return css_cls_state(cgroup_css(cgrp, net_cls_subsys_id));
-}
-
 static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
 {
 	return css_cls_state(task_css(p, net_cls_subsys_id));
@@ -87,14 +82,15 @@ static void cgrp_attach(struct cgroup_subsys_state *css,
 	}
 }
 
-static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
+static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-	return cgrp_cls_state(cgrp)->classid;
+	return css_cls_state(css)->classid;
 }
 
-static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
+static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
+			 u64 value)
 {
-	cgrp_cls_state(cgrp)->classid = (u32) value;
+	css_cls_state(css)->classid = (u32) value;
 	return 0;
 }