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, 18 insertions, 17 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 8ce3fdc3dfcc..89b76e1d3aa1 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1603,9 +1603,10 @@ typedef enum {
         FILE_SPREAD_SLAB,
 } cpuset_filetype_t;
 
-static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
+static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
+                            u64 val)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         cpuset_filetype_t type = cft->private;
         int retval = -ENODEV;
 
@@ -1650,9 +1651,10 @@ out_unlock:
         return retval;
 }
 
-static int cpuset_write_s64(struct cgroup *cgrp, struct cftype *cft, s64 val)
+static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
+                            s64 val)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         cpuset_filetype_t type = cft->private;
         int retval = -ENODEV;
 
@@ -1676,10 +1678,10 @@ out_unlock:
 /*
  * Common handling for a write to a "cpus" or "mems" file.
  */
-static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
-                                const char *buf)
+static int cpuset_write_resmask(struct cgroup_subsys_state *css,
+                                struct cftype *cft, const char *buf)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         struct cpuset *trialcs;
         int retval = -ENODEV;
 
@@ -1758,13 +1760,12 @@ static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs)
         return count;
 }
 
-static ssize_t cpuset_common_file_read(struct cgroup *cgrp,
-                                       struct cftype *cft,
-                                       struct file *file,
-                                       char __user *buf,
-                                       size_t nbytes, loff_t *ppos)
+static ssize_t cpuset_common_file_read(struct cgroup_subsys_state *css,
+                                       struct cftype *cft, struct file *file,
+                                       char __user *buf, size_t nbytes,
+                                       loff_t *ppos)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         cpuset_filetype_t type = cft->private;
         char *page;
         ssize_t retval = 0;
@@ -1794,9 +1795,9 @@ out:
         return retval;
 }
 
-static u64 cpuset_read_u64(struct cgroup *cgrp, struct cftype *cft)
+static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         cpuset_filetype_t type = cft->private;
         switch (type) {
         case FILE_CPU_EXCLUSIVE:
@@ -1825,9 +1826,9 @@ static u64 cpuset_read_u64(struct cgroup *cgrp, struct cftype *cft)
         return 0;
 }
 
-static s64 cpuset_read_s64(struct cgroup *cgrp, struct cftype *cft)
+static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *cs = css_cs(css);
         cpuset_filetype_t type = cft->private;
         switch (type) {
         case FILE_SCHED_RELAX_DOMAIN_LEVEL: