[RFC PATCH 1/9 v2] cgroup: change cgroup to css in rstat updated and flush api

[JP Kobryn <inwardvessel@gmail.com>]

Change rstat flush and updated API calls to accept a cgroup_subsys_state
instead of a cgroup.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
---
 block/blk-cgroup.c     |  4 ++--
 include/linux/cgroup.h |  8 ++++----
 kernel/cgroup/cgroup.c |  4 ++--
 kernel/cgroup/rstat.c  | 28 +++++++++++++++++++---------
 mm/memcontrol.c        |  4 ++--
 5 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 45a395862fbc..98e586ae21ec 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1200,7 +1200,7 @@ static int blkcg_print_stat(struct seq_file *sf, void *v)
 	if (!seq_css(sf)->parent)
 		blkcg_fill_root_iostats();
 	else
-		cgroup_rstat_flush(blkcg->css.cgroup);
+		cgroup_rstat_flush(&blkcg->css);
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
@@ -2183,7 +2183,7 @@ void blk_cgroup_bio_start(struct bio *bio)
 	}
 
 	u64_stats_update_end_irqrestore(&bis->sync, flags);
-	cgroup_rstat_updated(blkcg->css.cgroup, cpu);
+	cgroup_rstat_updated(&blkcg->css, cpu);
 	put_cpu();
 }
 
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index f8ef47f8a634..eec970622419 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -687,10 +687,10 @@ static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
 /*
  * cgroup scalable recursive statistics.
  */
-void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
-void cgroup_rstat_flush(struct cgroup *cgrp);
-void cgroup_rstat_flush_hold(struct cgroup *cgrp);
-void cgroup_rstat_flush_release(struct cgroup *cgrp);
+void cgroup_rstat_updated(struct cgroup_subsys_state *css, int cpu);
+void cgroup_rstat_flush(struct cgroup_subsys_state *css);
+void cgroup_rstat_flush_hold(struct cgroup_subsys_state *css);
+void cgroup_rstat_flush_release(struct cgroup_subsys_state *css);
 
 /*
  * Basic resource stats.
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 43c949824814..fdddd5ec5f3c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5465,7 +5465,7 @@ static void css_release_work_fn(struct work_struct *work)
 
 		/* css release path */
 		if (!list_empty(&css->rstat_css_node)) {
-			cgroup_rstat_flush(cgrp);
+			cgroup_rstat_flush(css);
 			list_del_rcu(&css->rstat_css_node);
 		}
 
@@ -5493,7 +5493,7 @@ static void css_release_work_fn(struct work_struct *work)
 		/* cgroup release path */
 		TRACE_CGROUP_PATH(release, cgrp);
 
-		cgroup_rstat_flush(cgrp);
+		cgroup_rstat_flush(css);
 
 		spin_lock_irq(&css_set_lock);
 		for (tcgrp = cgroup_parent(cgrp); tcgrp;
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 5877974ece92..1ed0f3aab0d9 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -82,8 +82,9 @@ void _cgroup_rstat_cpu_unlock(raw_spinlock_t *cpu_lock, int cpu,
  * rstat_cpu->updated_children list.  See the comment on top of
  * cgroup_rstat_cpu definition for details.
  */
-__bpf_kfunc void cgroup_rstat_updated(struct cgroup *cgrp, int cpu)
+__bpf_kfunc void cgroup_rstat_updated(struct cgroup_subsys_state *css, int cpu)
 {
+	struct cgroup *cgrp = css->cgroup;
 	raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
 	unsigned long flags;
 
@@ -346,8 +347,10 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp)
  *
  * This function may block.
  */
-__bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp)
+__bpf_kfunc void cgroup_rstat_flush(struct cgroup_subsys_state *css)
 {
+	struct cgroup *cgrp = css->cgroup;
+
 	might_sleep();
 
 	__cgroup_rstat_lock(cgrp, -1);
@@ -364,9 +367,11 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp)
  *
  * This function may block.
  */
-void cgroup_rstat_flush_hold(struct cgroup *cgrp)
+void cgroup_rstat_flush_hold(struct cgroup_subsys_state *css)
 	__acquires(&cgroup_rstat_lock)
 {
+	struct cgroup *cgrp = css->cgroup;
+
 	might_sleep();
 	__cgroup_rstat_lock(cgrp, -1);
 	cgroup_rstat_flush_locked(cgrp);
@@ -376,9 +381,11 @@ void cgroup_rstat_flush_hold(struct cgroup *cgrp)
  * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()
  * @cgrp: cgroup used by tracepoint
  */
-void cgroup_rstat_flush_release(struct cgroup *cgrp)
+void cgroup_rstat_flush_release(struct cgroup_subsys_state *css)
 	__releases(&cgroup_rstat_lock)
 {
+	struct cgroup *cgrp = css->cgroup;
+
 	__cgroup_rstat_unlock(cgrp, -1);
 }
 
@@ -408,7 +415,7 @@ void cgroup_rstat_exit(struct cgroup *cgrp)
 {
 	int cpu;
 
-	cgroup_rstat_flush(cgrp);
+	cgroup_rstat_flush(&cgrp->self);
 
 	/* sanity check */
 	for_each_possible_cpu(cpu) {
@@ -512,8 +519,10 @@ static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
 						 struct cgroup_rstat_cpu *rstatc,
 						 unsigned long flags)
 {
+	struct cgroup_subsys_state *css = &cgrp->self;
+
 	u64_stats_update_end_irqrestore(&rstatc->bsync, flags);
-	cgroup_rstat_updated(cgrp, smp_processor_id());
+	cgroup_rstat_updated(css, smp_processor_id());
 	put_cpu_ptr(rstatc);
 }
 
@@ -612,16 +621,17 @@ static void cgroup_force_idle_show(struct seq_file *seq, struct cgroup_base_stat
 
 void cgroup_base_stat_cputime_show(struct seq_file *seq)
 {
-	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct cgroup_subsys_state *css = seq_css(seq);
+	struct cgroup *cgrp = css->cgroup;
 	u64 usage, utime, stime, ntime;
 
 	if (cgroup_parent(cgrp)) {
-		cgroup_rstat_flush_hold(cgrp);
+		cgroup_rstat_flush_hold(css);
 		usage = cgrp->bstat.cputime.sum_exec_runtime;
 		cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime,
 			       &utime, &stime);
 		ntime = cgrp->bstat.ntime;
-		cgroup_rstat_flush_release(cgrp);
+		cgroup_rstat_flush_release(css);
 	} else {
 		/* cgrp->bstat of root is not actually used, reuse it */
 		root_cgroup_cputime(&cgrp->bstat);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7b3503d12aaf..97552476b844 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -579,7 +579,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
 	if (!val)
 		return;
 
-	cgroup_rstat_updated(memcg->css.cgroup, cpu);
+	cgroup_rstat_updated(&memcg->css, cpu);
 	statc = this_cpu_ptr(memcg->vmstats_percpu);
 	for (; statc; statc = statc->parent) {
 		stats_updates = READ_ONCE(statc->stats_updates) + abs(val);
@@ -611,7 +611,7 @@ static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force)
 	if (mem_cgroup_is_root(memcg))
 		WRITE_ONCE(flush_last_time, jiffies_64);
 
-	cgroup_rstat_flush(memcg->css.cgroup);
+	cgroup_rstat_flush(&memcg->css);
 }
 
 /*
-- 
2.47.1