cgroup: make hierarchy iterators deal with cgroup_subsys_state instead of cgroup
cgroup is currently in the process of transitioning to using css
(cgroup_subsys_state) as the primary handle instead of cgroup in
subsystem API. For hierarchy iterators, this is beneficial because
* In most cases, css is the only thing subsystems care about anyway.
* On the planned unified hierarchy, iterations for different
subsystems will need to skip over different subtrees of the
hierarchy depending on which subsystems are enabled on each cgroup.
Passing around css makes it unnecessary to explicitly specify the
subsystem in question as css is intersection between cgroup and
subsystem
* For the planned unified hierarchy, css's would need to be created
and destroyed dynamically independent from cgroup hierarchy. Having
cgroup core manage css iteration makes enforcing deref rules a lot
easier.
Most subsystem conversions are straight-forward. Noteworthy changes
are
* blkio: cgroup_to_blkcg() is no longer used. Removed.
* freezer: cgroup_freezer() is no longer used. Removed.
* devices: cgroup_to_devcgroup() is no longer used. 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>
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>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index f46f3c6..4b40640 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -614,7 +614,7 @@
{
struct blkcg_policy *pol = blkcg_policy[pd->plid];
struct blkcg_gq *pos_blkg;
- struct cgroup *pos_cgrp;
+ struct cgroup_subsys_state *pos_css;
u64 sum;
lockdep_assert_held(pd->blkg->q->queue_lock);
@@ -622,7 +622,7 @@
sum = blkg_stat_read((void *)pd + off);
rcu_read_lock();
- blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
+ blkg_for_each_descendant_pre(pos_blkg, pos_css, pd_to_blkg(pd)) {
struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
struct blkg_stat *stat = (void *)pos_pd + off;
@@ -649,7 +649,7 @@
{
struct blkcg_policy *pol = blkcg_policy[pd->plid];
struct blkcg_gq *pos_blkg;
- struct cgroup *pos_cgrp;
+ struct cgroup_subsys_state *pos_css;
struct blkg_rwstat sum;
int i;
@@ -658,7 +658,7 @@
sum = blkg_rwstat_read((void *)pd + off);
rcu_read_lock();
- blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
+ blkg_for_each_descendant_pre(pos_blkg, pos_css, pd_to_blkg(pd)) {
struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
struct blkg_rwstat *rwstat = (void *)pos_pd + off;
struct blkg_rwstat tmp;