diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt
index 1ee9caf..bd1ce15 100644
--- a/Documentation/cgroups/unified-hierarchy.txt
+++ b/Documentation/cgroups/unified-hierarchy.txt
@@ -27,7 +27,7 @@
     5-3-1. Format
     5-3-2. Control Knobs
   5-4. Per-Controller Changes
-    5-4-1. blkio
+    5-4-1. io
     5-4-2. cpuset
     5-4-3. memory
 6. Planned Changes
@@ -203,7 +203,7 @@
 universal, and there are various other knobs which simply aren't
 available for tasks.
 
-The blkio controller implicitly creates a hidden leaf node for each
+The io controller implicitly creates a hidden leaf node for each
 cgroup to host the tasks.  The hidden leaf has its own copies of all
 the knobs with "leaf_" prefixed.  While this allows equivalent control
 over internal tasks, it's with serious drawbacks.  It always adds an
@@ -438,9 +438,62 @@
 
 5-4. Per-Controller Changes
 
-5-4-1. blkio
+5-4-1. io
 
-- blk-throttle becomes properly hierarchical.
+- blkio is renamed to io.  The interface is overhauled anyway.  The
+  new name is more in line with the other two major controllers, cpu
+  and memory, and better suited given that it may be used for cgroup
+  writeback without involving block layer.
+
+- Everything including stat is always hierarchical making separate
+  recursive stat files pointless and, as no internal node can have
+  tasks, leaf weights are meaningless.  The operation model is
+  simplified and the interface is overhauled accordingly.
+
+  io.stat
+
+	The stat file.  The reported stats are from the point where
+	bio's are issued to request_queue.  The stats are counted
+	independent of which policies are enabled.  Each line in the
+	file follows the following format.  More fields may later be
+	added at the end.
+
+	  $MAJ:$MIN rbytes=$RBYTES wbytes=$WBYTES rios=$RIOS wrios=$WIOS
+
+  io.weight
+
+	The weight setting, currently only available and effective if
+	cfq-iosched is in use for the target device.  The weight is
+	between 10 and 1000 and defaults to 500.  The first line
+	always contains the default weight in the following format to
+	use when per-device setting is missing.
+
+	  default $WEIGHT
+
+	Subsequent lines list per-device weights of the following
+	format.
+
+	  $MAJ:$MIN $WEIGHT
+
+	Writing "$WEIGHT" or "default $WEIGHT" changes the default
+	setting.  Writing "$MAJ:$MIN $WEIGHT" sets per-device weight
+	while "$MAJ:$MIN default" clears it.
+
+	This file is available only on non-root cgroups.
+
+  io.max
+
+	The maximum bandwidth and/or iops setting, only available if
+	blk-throttle is enabled.  The file is of the following format.
+
+	  $MAJ:$MIN rbps=$RBPS wbps=$WBPS riops=$RIOPS wiops=$WIOPS
+
+	${R|W}BPS are read/write bytes per second and ${R|W}IOPS are
+	read/write IOs per second.  "max" indicates no limit.  Writing
+	to the file follows the same format but the individual
+	settings may be ommitted or specified in any order.
+
+	This file is available only on non-root cgroups.
 
 
 5-4-2. cpuset
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b5e72d7..88bdb73 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -854,6 +854,53 @@
 }
 EXPORT_SYMBOL_GPL(blkg_conf_finish);
 
+static int blkcg_print_stat(struct seq_file *sf, void *v)
+{
+	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+	struct blkcg_gq *blkg;
+
+	rcu_read_lock();
+
+	hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
+		const char *dname;
+		struct blkg_rwstat rwstat;
+		u64 rbytes, wbytes, rios, wios;
+
+		dname = blkg_dev_name(blkg);
+		if (!dname)
+			continue;
+
+		spin_lock_irq(blkg->q->queue_lock);
+
+		rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
+					offsetof(struct blkcg_gq, stat_bytes));
+		rbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
+		wbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
+
+		rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
+					offsetof(struct blkcg_gq, stat_ios));
+		rios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
+		wios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
+
+		spin_unlock_irq(blkg->q->queue_lock);
+
+		if (rbytes || wbytes || rios || wios)
+			seq_printf(sf, "%s rbytes=%llu wbytes=%llu rios=%llu wios=%llu\n",
+				   dname, rbytes, wbytes, rios, wios);
+	}
+
+	rcu_read_unlock();
+	return 0;
+}
+
+struct cftype blkcg_files[] = {
+	{
+		.name = "stat",
+		.seq_show = blkcg_print_stat,
+	},
+	{ }	/* terminate */
+};
+
 struct cftype blkcg_legacy_files[] = {
 	{
 		.name = "reset_stats",
@@ -1101,6 +1148,7 @@
 	.css_offline = blkcg_css_offline,
 	.css_free = blkcg_css_free,
 	.can_attach = blkcg_can_attach,
+	.dfl_cftypes = blkcg_files,
 	.legacy_cftypes = blkcg_legacy_files,
 	.legacy_name = "blkio",
 #ifdef CONFIG_MEMCG
@@ -1273,6 +1321,9 @@
 	mutex_unlock(&blkcg_pol_mutex);
 
 	/* everything is in place, add intf files for the new policy */
+	if (pol->dfl_cftypes)
+		WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys,
+					       pol->dfl_cftypes));
 	if (pol->legacy_cftypes)
 		WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys,
 						  pol->legacy_cftypes));
@@ -1312,6 +1363,8 @@
 		goto out_unlock;
 
 	/* kill the intf files first */
+	if (pol->dfl_cftypes)
+		cgroup_rm_cftypes(pol->dfl_cftypes);
 	if (pol->legacy_cftypes)
 		cgroup_rm_cftypes(pol->legacy_cftypes);
 
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a8bb2fd..c75a263 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1265,6 +1265,117 @@
 	{ }	/* terminate */
 };
 
+static u64 tg_prfill_max(struct seq_file *sf, struct blkg_policy_data *pd,
+			 int off)
+{
+	struct throtl_grp *tg = pd_to_tg(pd);
+	const char *dname = blkg_dev_name(pd->blkg);
+	char bufs[4][21] = { "max", "max", "max", "max" };
+
+	if (!dname)
+		return 0;
+	if (tg->bps[READ] == -1 && tg->bps[WRITE] == -1 &&
+	    tg->iops[READ] == -1 && tg->iops[WRITE] == -1)
+		return 0;
+
+	if (tg->bps[READ] != -1)
+		snprintf(bufs[0], sizeof(bufs[0]), "%llu", tg->bps[READ]);
+	if (tg->bps[WRITE] != -1)
+		snprintf(bufs[1], sizeof(bufs[1]), "%llu", tg->bps[WRITE]);
+	if (tg->iops[READ] != -1)
+		snprintf(bufs[2], sizeof(bufs[2]), "%u", tg->iops[READ]);
+	if (tg->iops[WRITE] != -1)
+		snprintf(bufs[3], sizeof(bufs[3]), "%u", tg->iops[WRITE]);
+
+	seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n",
+		   dname, bufs[0], bufs[1], bufs[2], bufs[3]);
+	return 0;
+}
+
+static int tg_print_max(struct seq_file *sf, void *v)
+{
+	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_max,
+			  &blkcg_policy_throtl, seq_cft(sf)->private, false);
+	return 0;
+}
+
+static ssize_t tg_set_max(struct kernfs_open_file *of,
+			  char *buf, size_t nbytes, loff_t off)
+{
+	struct blkcg *blkcg = css_to_blkcg(of_css(of));
+	struct blkg_conf_ctx ctx;
+	struct throtl_grp *tg;
+	u64 v[4];
+	int ret;
+
+	ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
+	if (ret)
+		return ret;
+
+	tg = blkg_to_tg(ctx.blkg);
+
+	v[0] = tg->bps[READ];
+	v[1] = tg->bps[WRITE];
+	v[2] = tg->iops[READ];
+	v[3] = tg->iops[WRITE];
+
+	while (true) {
+		char tok[27];	/* wiops=18446744073709551616 */
+		char *p;
+		u64 val = -1;
+		int len;
+
+		if (sscanf(ctx.body, "%26s%n", tok, &len) != 1)
+			break;
+		if (tok[0] == '\0')
+			break;
+		ctx.body += len;
+
+		ret = -EINVAL;
+		p = tok;
+		strsep(&p, "=");
+		if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max")))
+			goto out_finish;
+
+		ret = -ERANGE;
+		if (!val)
+			goto out_finish;
+
+		ret = -EINVAL;
+		if (!strcmp(tok, "rbps"))
+			v[0] = val;
+		else if (!strcmp(tok, "wbps"))
+			v[1] = val;
+		else if (!strcmp(tok, "riops"))
+			v[2] = min_t(u64, val, UINT_MAX);
+		else if (!strcmp(tok, "wiops"))
+			v[3] = min_t(u64, val, UINT_MAX);
+		else
+			goto out_finish;
+	}
+
+	tg->bps[READ] = v[0];
+	tg->bps[WRITE] = v[1];
+	tg->iops[READ] = v[2];
+	tg->iops[WRITE] = v[3];
+
+	tg_conf_updated(tg);
+	ret = 0;
+out_finish:
+	blkg_conf_finish(&ctx);
+	return ret ?: nbytes;
+}
+
+static struct cftype throtl_files[] = {
+	{
+		.name = "max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = tg_print_max,
+		.write = tg_set_max,
+	},
+	{ }	/* terminate */
+};
+
 static void throtl_shutdown_wq(struct request_queue *q)
 {
 	struct throtl_data *td = q->td;
@@ -1273,6 +1384,7 @@
 }
 
 static struct blkcg_policy blkcg_policy_throtl = {
+	.dfl_cftypes		= throtl_files,
 	.legacy_cftypes		= throtl_legacy_files,
 
 	.pd_alloc_fn		= throtl_pd_alloc,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 7a72301..97da571 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1740,7 +1740,7 @@
 
 static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
 					char *buf, size_t nbytes, loff_t off,
-					bool is_leaf_weight)
+					bool on_dfl, bool is_leaf_weight)
 {
 	struct blkcg *blkcg = css_to_blkcg(of_css(of));
 	struct blkg_conf_ctx ctx;
@@ -1753,9 +1753,17 @@
 	if (ret)
 		return ret;
 
-	ret = -EINVAL;
-	if (sscanf(ctx.body, "%llu", &v) != 1)
+	if (sscanf(ctx.body, "%llu", &v) == 1) {
+		/* require "default" on dfl */
+		ret = -ERANGE;
+		if (!v && on_dfl)
+			goto out_finish;
+	} else if (!strcmp(strim(ctx.body), "default")) {
+		v = 0;
+	} else {
+		ret = -EINVAL;
 		goto out_finish;
+	}
 
 	cfqg = blkg_to_cfqg(ctx.blkg);
 	cfqgd = blkcg_to_cfqgd(blkcg);
@@ -1779,13 +1787,13 @@
 static ssize_t cfqg_set_weight_device(struct kernfs_open_file *of,
 				      char *buf, size_t nbytes, loff_t off)
 {
-	return __cfqg_set_weight_device(of, buf, nbytes, off, false);
+	return __cfqg_set_weight_device(of, buf, nbytes, off, false, false);
 }
 
 static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
 					   char *buf, size_t nbytes, loff_t off)
 {
-	return __cfqg_set_weight_device(of, buf, nbytes, off, true);
+	return __cfqg_set_weight_device(of, buf, nbytes, off, false, true);
 }
 
 static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
@@ -2103,6 +2111,48 @@
 #endif	/* CONFIG_DEBUG_BLK_CGROUP */
 	{ }	/* terminate */
 };
+
+static int cfq_print_weight_on_dfl(struct seq_file *sf, void *v)
+{
+	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+	struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
+
+	seq_printf(sf, "default %u\n", cgd->weight);
+	blkcg_print_blkgs(sf, blkcg, cfqg_prfill_weight_device,
+			  &blkcg_policy_cfq, 0, false);
+	return 0;
+}
+
+static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of,
+				     char *buf, size_t nbytes, loff_t off)
+{
+	char *endp;
+	int ret;
+	u64 v;
+
+	buf = strim(buf);
+
+	/* "WEIGHT" or "default WEIGHT" sets the default weight */
+	v = simple_strtoull(buf, &endp, 0);
+	if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
+		ret = __cfq_set_weight(of_css(of), v, false);
+		return ret ?: nbytes;
+	}
+
+	/* "MAJ:MIN WEIGHT" */
+	return __cfqg_set_weight_device(of, buf, nbytes, off, true, false);
+}
+
+static struct cftype cfq_blkcg_files[] = {
+	{
+		.name = "weight",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cfq_print_weight_on_dfl,
+		.write = cfq_set_weight_on_dfl,
+	},
+	{ }	/* terminate */
+};
+
 #else /* GROUP_IOSCHED */
 static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
 					 struct blkcg *blkcg)
@@ -4659,6 +4709,7 @@
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
 static struct blkcg_policy blkcg_policy_cfq = {
+	.dfl_cftypes		= cfq_blkcg_files,
 	.legacy_cftypes		= cfq_blkcg_legacy_files,
 
 	.cpd_alloc_fn		= cfq_cpd_alloc,
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index b270aef..9a7c4bd 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -148,6 +148,7 @@
 struct blkcg_policy {
 	int				plid;
 	/* cgroup files for the policy */
+	struct cftype			*dfl_cftypes;
 	struct cftype			*legacy_cftypes;
 
 	/* operations */