3 files changed, 17 insertions, 24 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index f46f3c69179c..4b40640240a4 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -614,7 +614,7 @@ u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off)
 {
         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 @@ u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off)
         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 blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
 {
         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 @@ struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
         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;
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index b6802c46d68f..855538630300 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -184,11 +184,6 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
         return css ? container_of(css, struct blkcg, css) : NULL;
 }
 
-static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup)
-{
-        return css_to_blkcg(cgroup_css(cgroup, blkio_subsys_id));
-}
-
 static inline struct blkcg *task_blkcg(struct task_struct *tsk)
 {
         return css_to_blkcg(task_css(tsk, blkio_subsys_id));
@@ -289,32 +284,31 @@ struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
 /**
  * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
  * @d_blkg: loop cursor pointing to the current descendant
- * @pos_cgrp: used for iteration
+ * @pos_css: used for iteration
  * @p_blkg: target blkg to walk descendants of
  *
  * Walk @c_blkg through the descendants of @p_blkg.  Must be used with RCU
  * read locked.  If called under either blkcg or queue lock, the iteration
  * is guaranteed to include all and only online blkgs.  The caller may
- * update @pos_cgrp by calling cgroup_rightmost_descendant() to skip
- * subtree.
+ * update @pos_css by calling css_rightmost_descendant() to skip subtree.
  */
-#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg)          \
-        cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \
-                if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \
+#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg)           \
+        css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css)   \
+                if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),    \
                                               (p_blkg)->q, false)))
 
 /**
  * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
  * @d_blkg: loop cursor pointing to the current descendant
- * @pos_cgrp: used for iteration
+ * @pos_css: used for iteration
  * @p_blkg: target blkg to walk descendants of
  *
  * Similar to blkg_for_each_descendant_pre() but performs post-order
  * traversal instead.  Synchronization rules are the same.
  */
-#define blkg_for_each_descendant_post(d_blkg, pos_cgrp, p_blkg)         \
-        cgroup_for_each_descendant_post((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \
-                if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \
+#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg)          \
+        css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css)  \
+                if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),    \
                                               (p_blkg)->q, false)))
 
 /**
@@ -577,7 +571,6 @@ static inline int blkcg_activate_policy(struct request_queue *q,
 static inline void blkcg_deactivate_policy(struct request_queue *q,
                                            const struct blkcg_policy *pol) { }
 
-static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; }
 static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
 
 static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 88bcfb651b0b..8cefa7f8590e 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1349,7 +1349,7 @@ static int tg_set_conf(struct cgroup_subsys_state *css, struct cftype *cft,
         struct throtl_grp *tg;
         struct throtl_service_queue *sq;
         struct blkcg_gq *blkg;
-        struct cgroup *pos_cgrp;
+        struct cgroup_subsys_state *pos_css;
         int ret;
 
         ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
@@ -1380,7 +1380,7 @@ static int tg_set_conf(struct cgroup_subsys_state *css, struct cftype *cft,
          * blk-throttle.
          */
         tg_update_has_rules(tg);
-        blkg_for_each_descendant_pre(blkg, pos_cgrp, ctx.blkg)
+        blkg_for_each_descendant_pre(blkg, pos_css, ctx.blkg)
                 tg_update_has_rules(blkg_to_tg(blkg));
 
         /*
@@ -1623,7 +1623,7 @@ void blk_throtl_drain(struct request_queue *q)
 {
         struct throtl_data *td = q->td;
         struct blkcg_gq *blkg;
-        struct cgroup *pos_cgrp;
+        struct cgroup_subsys_state *pos_css;
         struct bio *bio;
         int rw;
 
@@ -1636,7 +1636,7 @@ void blk_throtl_drain(struct request_queue *q)
          * better to walk service_queue tree directly but blkg walk is
          * easier.
          */
-        blkg_for_each_descendant_post(blkg, pos_cgrp, td->queue->root_blkg)
+        blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg)
                 tg_drain_bios(&blkg_to_tg(blkg)->service_queue);
 
         tg_drain_bios(&td_root_tg(td)->service_queue);