blkcg: mass rename of blkcg API

During the recent blkcg cleanup, most of blkcg API has changed to such
extent that mass renaming wouldn't cause any noticeable pain.  Take
the chance and cleanup the naming.

* Rename blkio_cgroup to blkcg.

* Drop blkio / blkiocg prefixes and consistently use blkcg.

* Rename blkio_group to blkcg_gq, which is consistent with io_cq but
  keep the blkg prefix / variable name.

* Rename policy method type and field names to signify they're dealing
  with policy data.

* Rename blkio_policy_type to blkcg_policy.

This patch doesn't cause any functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 901286b..7922182 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -17,7 +17,7 @@
 #include "blk.h"
 #include "blk-cgroup.h"
 
-static struct blkio_policy_type blkio_policy_cfq __maybe_unused;
+static struct blkcg_policy blkcg_policy_cfq __maybe_unused;
 
 /*
  * tunables
@@ -202,7 +202,7 @@
 	struct blkg_stat		dequeue;
 	/* total time spent waiting for it to be assigned a timeslice. */
 	struct blkg_stat		group_wait_time;
-	/* time spent idling for this blkio_group */
+	/* time spent idling for this blkcg_gq */
 	struct blkg_stat		idle_time;
 	/* total time with empty current active q with other requests queued */
 	struct blkg_stat		empty_time;
@@ -553,12 +553,12 @@
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
 
-static inline struct cfq_group *blkg_to_cfqg(struct blkio_group *blkg)
+static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg)
 {
-	return blkg_to_pdata(blkg, &blkio_policy_cfq);
+	return blkg_to_pdata(blkg, &blkcg_policy_cfq);
 }
 
-static inline struct blkio_group *cfqg_to_blkg(struct cfq_group *cfqg)
+static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
 {
 	return pdata_to_blkg(cfqg);
 }
@@ -637,7 +637,7 @@
 				io_start_time - start_time);
 }
 
-static void cfqg_stats_reset(struct blkio_group *blkg)
+static void cfq_pd_reset_stats(struct blkcg_gq *blkg)
 {
 	struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 	struct cfqg_stats *stats = &cfqg->stats;
@@ -662,8 +662,8 @@
 
 #else	/* CONFIG_CFQ_GROUP_IOSCHED */
 
-static inline struct cfq_group *blkg_to_cfqg(struct blkio_group *blkg) { return NULL; }
-static inline struct blkio_group *cfqg_to_blkg(struct cfq_group *cfqg) { return NULL; }
+static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) { return NULL; }
+static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg) { return NULL; }
 static inline void cfqg_get(struct cfq_group *cfqg) { }
 static inline void cfqg_put(struct cfq_group *cfqg) { }
 
@@ -1331,7 +1331,7 @@
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void cfq_init_blkio_group(struct blkio_group *blkg)
+static void cfq_pd_init(struct blkcg_gq *blkg)
 {
 	struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 
@@ -1344,16 +1344,16 @@
  * be held.
  */
 static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd,
-						struct blkio_cgroup *blkcg)
+						struct blkcg *blkcg)
 {
 	struct request_queue *q = cfqd->queue;
 	struct cfq_group *cfqg = NULL;
 
-	/* avoid lookup for the common case where there's no blkio cgroup */
-	if (blkcg == &blkio_root_cgroup) {
+	/* avoid lookup for the common case where there's no blkcg */
+	if (blkcg == &blkcg_root) {
 		cfqg = cfqd->root_group;
 	} else {
-		struct blkio_group *blkg;
+		struct blkcg_gq *blkg;
 
 		blkg = blkg_lookup_create(blkcg, q);
 		if (!IS_ERR(blkg))
@@ -1386,8 +1386,8 @@
 static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft,
 				    struct seq_file *sf)
 {
-	blkcg_print_blkgs(sf, cgroup_to_blkio_cgroup(cgrp),
-			  cfqg_prfill_weight_device, &blkio_policy_cfq, 0,
+	blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp),
+			  cfqg_prfill_weight_device, &blkcg_policy_cfq, 0,
 			  false);
 	return 0;
 }
@@ -1395,19 +1395,19 @@
 static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft,
 			    struct seq_file *sf)
 {
-	seq_printf(sf, "%u\n", cgroup_to_blkio_cgroup(cgrp)->cfq_weight);
+	seq_printf(sf, "%u\n", cgroup_to_blkcg(cgrp)->cfq_weight);
 	return 0;
 }
 
 static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
 				  const char *buf)
 {
-	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 	struct blkg_conf_ctx ctx;
 	struct cfq_group *cfqg;
 	int ret;
 
-	ret = blkg_conf_prep(blkcg, &blkio_policy_cfq, buf, &ctx);
+	ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx);
 	if (ret)
 		return ret;
 
@@ -1425,8 +1425,8 @@
 
 static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
 {
-	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
-	struct blkio_group *blkg;
+	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
+	struct blkcg_gq *blkg;
 	struct hlist_node *n;
 
 	if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX)
@@ -1449,9 +1449,9 @@
 static int cfqg_print_stat(struct cgroup *cgrp, struct cftype *cft,
 			   struct seq_file *sf)
 {
-	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 
-	blkcg_print_blkgs(sf, blkcg, blkg_prfill_stat, &blkio_policy_cfq,
+	blkcg_print_blkgs(sf, blkcg, blkg_prfill_stat, &blkcg_policy_cfq,
 			  cft->private, false);
 	return 0;
 }
@@ -1459,9 +1459,9 @@
 static int cfqg_print_rwstat(struct cgroup *cgrp, struct cftype *cft,
 			     struct seq_file *sf)
 {
-	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 
-	blkcg_print_blkgs(sf, blkcg, blkg_prfill_rwstat, &blkio_policy_cfq,
+	blkcg_print_blkgs(sf, blkcg, blkg_prfill_rwstat, &blkcg_policy_cfq,
 			  cft->private, true);
 	return 0;
 }
@@ -1485,10 +1485,10 @@
 static int cfqg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft,
 				     struct seq_file *sf)
 {
-	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 
 	blkcg_print_blkgs(sf, blkcg, cfqg_prfill_avg_queue_size,
-			  &blkio_policy_cfq, 0, false);
+			  &blkcg_policy_cfq, 0, false);
 	return 0;
 }
 #endif	/* CONFIG_DEBUG_BLK_CGROUP */
@@ -1580,7 +1580,7 @@
 };
 #else /* GROUP_IOSCHED */
 static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd,
-						struct blkio_cgroup *blkcg)
+						struct blkcg *blkcg)
 {
 	return cfqd->root_group;
 }
@@ -3135,7 +3135,7 @@
 	uint64_t id;
 
 	rcu_read_lock();
-	id = bio_blkio_cgroup(bio)->id;
+	id = bio_blkcg(bio)->id;
 	rcu_read_unlock();
 
 	/*
@@ -3166,14 +3166,14 @@
 cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
 		     struct bio *bio, gfp_t gfp_mask)
 {
-	struct blkio_cgroup *blkcg;
+	struct blkcg *blkcg;
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
 	struct cfq_group *cfqg;
 
 retry:
 	rcu_read_lock();
 
-	blkcg = bio_blkio_cgroup(bio);
+	blkcg = bio_blkcg(bio);
 	cfqg = cfq_lookup_create_cfqg(cfqd, blkcg);
 	cfqq = cic_to_cfqq(cic, is_sync);
 
@@ -3944,14 +3944,14 @@
 #ifndef CONFIG_CFQ_GROUP_IOSCHED
 	kfree(cfqd->root_group);
 #endif
-	blkcg_deactivate_policy(q, &blkio_policy_cfq);
+	blkcg_deactivate_policy(q, &blkcg_policy_cfq);
 	kfree(cfqd);
 }
 
 static int cfq_init_queue(struct request_queue *q)
 {
 	struct cfq_data *cfqd;
-	struct blkio_group *blkg __maybe_unused;
+	struct blkcg_gq *blkg __maybe_unused;
 	int i, ret;
 
 	cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
@@ -3966,7 +3966,7 @@
 
 	/* Init root group and prefer root group over other groups by default */
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
-	ret = blkcg_activate_policy(q, &blkio_policy_cfq);
+	ret = blkcg_activate_policy(q, &blkcg_policy_cfq);
 	if (ret)
 		goto out_free;
 
@@ -4156,10 +4156,10 @@
 };
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
-static struct blkio_policy_type blkio_policy_cfq = {
+static struct blkcg_policy blkcg_policy_cfq = {
 	.ops = {
-		.blkio_init_group_fn =		cfq_init_blkio_group,
-		.blkio_reset_group_stats_fn =	cfqg_stats_reset,
+		.pd_init_fn		= cfq_pd_init,
+		.pd_reset_stats_fn	= cfq_pd_reset_stats,
 	},
 	.pdata_size = sizeof(struct cfq_group),
 	.cftypes = cfq_blkcg_files,
@@ -4185,7 +4185,7 @@
 		cfq_group_idle = 0;
 #endif
 
-	ret = blkio_policy_register(&blkio_policy_cfq);
+	ret = blkcg_policy_register(&blkcg_policy_cfq);
 	if (ret)
 		return ret;
 
@@ -4202,13 +4202,13 @@
 err_free_pool:
 	kmem_cache_destroy(cfq_pool);
 err_pol_unreg:
-	blkio_policy_unregister(&blkio_policy_cfq);
+	blkcg_policy_unregister(&blkcg_policy_cfq);
 	return ret;
 }
 
 static void __exit cfq_exit(void)
 {
-	blkio_policy_unregister(&blkio_policy_cfq);
+	blkcg_policy_unregister(&blkcg_policy_cfq);
 	elv_unregister(&iosched_cfq);
 	kmem_cache_destroy(cfq_pool);
 }