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, 11 insertions, 15 deletions

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index e2132435060..bda8e44f6fd 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -40,12 +40,6 @@ struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
 }
 
 static inline
-struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup)
-{
-	return hugetlb_cgroup_from_css(cgroup_css(cgroup, hugetlb_subsys_id));
-}
-
-static inline
 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
 {
 	return hugetlb_cgroup_from_css(task_css(task, hugetlb_subsys_id));
@@ -248,14 +242,15 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
 	return;
 }
 
-static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft,
-				   struct file *file, char __user *buf,
-				   size_t nbytes, loff_t *ppos)
+static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css,
+				   struct cftype *cft, struct file *file,
+				   char __user *buf, size_t nbytes,
+				   loff_t *ppos)
 {
 	u64 val;
 	char str[64];
 	int idx, name, len;
-	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
+	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 
 	idx = MEMFILE_IDX(cft->private);
 	name = MEMFILE_ATTR(cft->private);
@@ -265,12 +260,12 @@ static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft,
 	return simple_read_from_buffer(buf, nbytes, ppos, str, len);
 }
 
-static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft,
-				const char *buffer)
+static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
+				struct cftype *cft, const char *buffer)
 {
 	int idx, name, ret;
 	unsigned long long val;
-	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
+	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 
 	idx = MEMFILE_IDX(cft->private);
 	name = MEMFILE_ATTR(cft->private);
@@ -295,10 +290,11 @@ static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft,
 	return ret;
 }
 
-static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
+static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css,
+				unsigned int event)
 {
 	int idx, name, ret = 0;
-	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
+	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 
 	idx = MEMFILE_IDX(event);
 	name = MEMFILE_ATTR(event);