These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 786 insertions, 0 deletions

diff --git a/kernel/include/linux/blk-cgroup.h b/kernel/include/linux/blk-cgroup.h
new file mode 100644
index 000000000..c02e66994
--- /dev/null
+++ b/kernel/include/linux/blk-cgroup.h
@@ -0,0 +1,786 @@
+#ifndef _BLK_CGROUP_H
+#define _BLK_CGROUP_H
+/*
+ * Common Block IO controller cgroup interface
+ *
+ * Based on ideas and code from CFQ, CFS and BFQ:
+ * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
+ *
+ * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
+ *		      Paolo Valente <paolo.valente@unimore.it>
+ *
+ * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
+ * 	              Nauman Rafique <nauman@google.com>
+ */
+
+#include <linux/cgroup.h>
+#include <linux/percpu_counter.h>
+#include <linux/seq_file.h>
+#include <linux/radix-tree.h>
+#include <linux/blkdev.h>
+#include <linux/atomic.h>
+
+/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
+#define BLKG_STAT_CPU_BATCH	(INT_MAX / 2)
+
+/* Max limits for throttle policy */
+#define THROTL_IOPS_MAX		UINT_MAX
+
+#ifdef CONFIG_BLK_CGROUP
+
+enum blkg_rwstat_type {
+	BLKG_RWSTAT_READ,
+	BLKG_RWSTAT_WRITE,
+	BLKG_RWSTAT_SYNC,
+	BLKG_RWSTAT_ASYNC,
+
+	BLKG_RWSTAT_NR,
+	BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
+};
+
+struct blkcg_gq;
+
+struct blkcg {
+	struct cgroup_subsys_state	css;
+	spinlock_t			lock;
+
+	struct radix_tree_root		blkg_tree;
+	struct blkcg_gq			*blkg_hint;
+	struct hlist_head		blkg_list;
+
+	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];
+
+	struct list_head		all_blkcgs_node;
+#ifdef CONFIG_CGROUP_WRITEBACK
+	struct list_head		cgwb_list;
+#endif
+};
+
+/*
+ * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
+ * recursive.  Used to carry stats of dead children, and, for blkg_rwstat,
+ * to carry result values from read and sum operations.
+ */
+struct blkg_stat {
+	struct percpu_counter		cpu_cnt;
+	atomic64_t			aux_cnt;
+};
+
+struct blkg_rwstat {
+	struct percpu_counter		cpu_cnt[BLKG_RWSTAT_NR];
+	atomic64_t			aux_cnt[BLKG_RWSTAT_NR];
+};
+
+/*
+ * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
+ * request_queue (q).  This is used by blkcg policies which need to track
+ * information per blkcg - q pair.
+ *
+ * There can be multiple active blkcg policies and each blkg:policy pair is
+ * represented by a blkg_policy_data which is allocated and freed by each
+ * policy's pd_alloc/free_fn() methods.  A policy can allocate private data
+ * area by allocating larger data structure which embeds blkg_policy_data
+ * at the beginning.
+ */
+struct blkg_policy_data {
+	/* the blkg and policy id this per-policy data belongs to */
+	struct blkcg_gq			*blkg;
+	int				plid;
+};
+
+/*
+ * Policies that need to keep per-blkcg data which is independent from any
+ * request_queue associated to it should implement cpd_alloc/free_fn()
+ * methods.  A policy can allocate private data area by allocating larger
+ * data structure which embeds blkcg_policy_data at the beginning.
+ * cpd_init() is invoked to let each policy handle per-blkcg data.
+ */
+struct blkcg_policy_data {
+	/* the blkcg and policy id this per-policy data belongs to */
+	struct blkcg			*blkcg;
+	int				plid;
+};
+
+/* association between a blk cgroup and a request queue */
+struct blkcg_gq {
+	/* Pointer to the associated request_queue */
+	struct request_queue		*q;
+	struct list_head		q_node;
+	struct hlist_node		blkcg_node;
+	struct blkcg			*blkcg;
+
+	/*
+	 * Each blkg gets congested separately and the congestion state is
+	 * propagated to the matching bdi_writeback_congested.
+	 */
+	struct bdi_writeback_congested	*wb_congested;
+
+	/* all non-root blkcg_gq's are guaranteed to have access to parent */
+	struct blkcg_gq			*parent;
+
+	/* request allocation list for this blkcg-q pair */
+	struct request_list		rl;
+
+	/* reference count */
+	atomic_t			refcnt;
+
+	/* is this blkg online? protected by both blkcg and q locks */
+	bool				online;
+
+	struct blkg_rwstat		stat_bytes;
+	struct blkg_rwstat		stat_ios;
+
+	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];
+
+	struct rcu_head			rcu_head;
+};
+
+typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
+typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
+typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
+
+struct blkcg_policy {
+	int				plid;
+	/* cgroup files for the policy */
+	struct cftype			*dfl_cftypes;
+	struct cftype			*legacy_cftypes;
+
+	/* operations */
+	blkcg_pol_alloc_cpd_fn		*cpd_alloc_fn;
+	blkcg_pol_init_cpd_fn		*cpd_init_fn;
+	blkcg_pol_free_cpd_fn		*cpd_free_fn;
+	blkcg_pol_bind_cpd_fn		*cpd_bind_fn;
+
+	blkcg_pol_alloc_pd_fn		*pd_alloc_fn;
+	blkcg_pol_init_pd_fn		*pd_init_fn;
+	blkcg_pol_online_pd_fn		*pd_online_fn;
+	blkcg_pol_offline_pd_fn		*pd_offline_fn;
+	blkcg_pol_free_pd_fn		*pd_free_fn;
+	blkcg_pol_reset_pd_stats_fn	*pd_reset_stats_fn;
+};
+
+extern struct blkcg blkcg_root;
+extern struct cgroup_subsys_state * const blkcg_root_css;
+
+struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
+				      struct request_queue *q, bool update_hint);
+struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
+				    struct request_queue *q);
+int blkcg_init_queue(struct request_queue *q);
+void blkcg_drain_queue(struct request_queue *q);
+void blkcg_exit_queue(struct request_queue *q);
+
+/* Blkio controller policy registration */
+int blkcg_policy_register(struct blkcg_policy *pol);
+void blkcg_policy_unregister(struct blkcg_policy *pol);
+int blkcg_activate_policy(struct request_queue *q,
+			  const struct blkcg_policy *pol);
+void blkcg_deactivate_policy(struct request_queue *q,
+			     const struct blkcg_policy *pol);
+
+const char *blkg_dev_name(struct blkcg_gq *blkg);
+void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
+		       u64 (*prfill)(struct seq_file *,
+				     struct blkg_policy_data *, int),
+		       const struct blkcg_policy *pol, int data,
+		       bool show_total);
+u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
+u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+			 const struct blkg_rwstat *rwstat);
+u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
+u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+		       int off);
+int blkg_print_stat_bytes(struct seq_file *sf, void *v);
+int blkg_print_stat_ios(struct seq_file *sf, void *v);
+int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
+int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
+
+u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
+			    struct blkcg_policy *pol, int off);
+struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
+					     struct blkcg_policy *pol, int off);
+
+struct blkg_conf_ctx {
+	struct gendisk			*disk;
+	struct blkcg_gq			*blkg;
+	char				*body;
+};
+
+int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
+		   char *input, struct blkg_conf_ctx *ctx);
+void blkg_conf_finish(struct blkg_conf_ctx *ctx);
+
+
+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 *task_blkcg(struct task_struct *tsk)
+{
+	return css_to_blkcg(task_css(tsk, io_cgrp_id));
+}
+
+static inline struct blkcg *bio_blkcg(struct bio *bio)
+{
+	if (bio && bio->bi_css)
+		return css_to_blkcg(bio->bi_css);
+	return task_blkcg(current);
+}
+
+static inline struct cgroup_subsys_state *
+task_get_blkcg_css(struct task_struct *task)
+{
+	return task_get_css(task, io_cgrp_id);
+}
+
+/**
+ * blkcg_parent - get the parent of a blkcg
+ * @blkcg: blkcg of interest
+ *
+ * Return the parent blkcg of @blkcg.  Can be called anytime.
+ */
+static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
+{
+	return css_to_blkcg(blkcg->css.parent);
+}
+
+/**
+ * __blkg_lookup - internal version of blkg_lookup()
+ * @blkcg: blkcg of interest
+ * @q: request_queue of interest
+ * @update_hint: whether to update lookup hint with the result or not
+ *
+ * This is internal version and shouldn't be used by policy
+ * implementations.  Looks up blkgs for the @blkcg - @q pair regardless of
+ * @q's bypass state.  If @update_hint is %true, the caller should be
+ * holding @q->queue_lock and lookup hint is updated on success.
+ */
+static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
+					     struct request_queue *q,
+					     bool update_hint)
+{
+	struct blkcg_gq *blkg;
+
+	if (blkcg == &blkcg_root)
+		return q->root_blkg;
+
+	blkg = rcu_dereference(blkcg->blkg_hint);
+	if (blkg && blkg->q == q)
+		return blkg;
+
+	return blkg_lookup_slowpath(blkcg, q, update_hint);
+}
+
+/**
+ * blkg_lookup - lookup blkg for the specified blkcg - q pair
+ * @blkcg: blkcg of interest
+ * @q: request_queue of interest
+ *
+ * Lookup blkg for the @blkcg - @q pair.  This function should be called
+ * under RCU read lock and is guaranteed to return %NULL if @q is bypassing
+ * - see blk_queue_bypass_start() for details.
+ */
+static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
+					   struct request_queue *q)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	if (unlikely(blk_queue_bypass(q)))
+		return NULL;
+	return __blkg_lookup(blkcg, q, false);
+}
+
+/**
+ * blkg_to_pdata - get policy private data
+ * @blkg: blkg of interest
+ * @pol: policy of interest
+ *
+ * Return pointer to private data associated with the @blkg-@pol pair.
+ */
+static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
+						  struct blkcg_policy *pol)
+{
+	return blkg ? blkg->pd[pol->plid] : NULL;
+}
+
+static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
+						     struct blkcg_policy *pol)
+{
+	return blkcg ? blkcg->cpd[pol->plid] : NULL;
+}
+
+/**
+ * pdata_to_blkg - get blkg associated with policy private data
+ * @pd: policy private data of interest
+ *
+ * @pd is policy private data.  Determine the blkg it's associated with.
+ */
+static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
+{
+	return pd ? pd->blkg : NULL;
+}
+
+static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
+{
+	return cpd ? cpd->blkcg : NULL;
+}
+
+/**
+ * blkg_path - format cgroup path of blkg
+ * @blkg: blkg of interest
+ * @buf: target buffer
+ * @buflen: target buffer length
+ *
+ * Format the path of the cgroup of @blkg into @buf.
+ */
+static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
+{
+	char *p;
+
+	p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
+	if (!p) {
+		strncpy(buf, "<unavailable>", buflen);
+		return -ENAMETOOLONG;
+	}
+
+	memmove(buf, p, buf + buflen - p);
+	return 0;
+}
+
+/**
+ * blkg_get - get a blkg reference
+ * @blkg: blkg to get
+ *
+ * The caller should be holding an existing reference.
+ */
+static inline void blkg_get(struct blkcg_gq *blkg)
+{
+	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
+	atomic_inc(&blkg->refcnt);
+}
+
+void __blkg_release_rcu(struct rcu_head *rcu);
+
+/**
+ * blkg_put - put a blkg reference
+ * @blkg: blkg to put
+ */
+static inline void blkg_put(struct blkcg_gq *blkg)
+{
+	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
+	if (atomic_dec_and_test(&blkg->refcnt))
+		call_rcu(&blkg->rcu_head, __blkg_release_rcu);
+}
+
+/**
+ * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @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_css by calling css_rightmost_descendant() to skip subtree.
+ * @p_blkg is included in the iteration and the first node to be visited.
+ */
+#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_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.  @p_blkg is
+ * included in the iteration and the last node to be visited.
+ */
+#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)))
+
+/**
+ * blk_get_rl - get request_list to use
+ * @q: request_queue of interest
+ * @bio: bio which will be attached to the allocated request (may be %NULL)
+ *
+ * The caller wants to allocate a request from @q to use for @bio.  Find
+ * the request_list to use and obtain a reference on it.  Should be called
+ * under queue_lock.  This function is guaranteed to return non-%NULL
+ * request_list.
+ */
+static inline struct request_list *blk_get_rl(struct request_queue *q,
+					      struct bio *bio)
+{
+	struct blkcg *blkcg;
+	struct blkcg_gq *blkg;
+
+	rcu_read_lock();
+
+	blkcg = bio_blkcg(bio);
+
+	/* bypass blkg lookup and use @q->root_rl directly for root */
+	if (blkcg == &blkcg_root)
+		goto root_rl;
+
+	/*
+	 * Try to use blkg->rl.  blkg lookup may fail under memory pressure
+	 * or if either the blkcg or queue is going away.  Fall back to
+	 * root_rl in such cases.
+	 */
+	blkg = blkg_lookup(blkcg, q);
+	if (unlikely(!blkg))
+		goto root_rl;
+
+	blkg_get(blkg);
+	rcu_read_unlock();
+	return &blkg->rl;
+root_rl:
+	rcu_read_unlock();
+	return &q->root_rl;
+}
+
+/**
+ * blk_put_rl - put request_list
+ * @rl: request_list to put
+ *
+ * Put the reference acquired by blk_get_rl().  Should be called under
+ * queue_lock.
+ */
+static inline void blk_put_rl(struct request_list *rl)
+{
+	if (rl->blkg->blkcg != &blkcg_root)
+		blkg_put(rl->blkg);
+}
+
+/**
+ * blk_rq_set_rl - associate a request with a request_list
+ * @rq: request of interest
+ * @rl: target request_list
+ *
+ * Associate @rq with @rl so that accounting and freeing can know the
+ * request_list @rq came from.
+ */
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
+{
+	rq->rl = rl;
+}
+
+/**
+ * blk_rq_rl - return the request_list a request came from
+ * @rq: request of interest
+ *
+ * Return the request_list @rq is allocated from.
+ */
+static inline struct request_list *blk_rq_rl(struct request *rq)
+{
+	return rq->rl;
+}
+
+struct request_list *__blk_queue_next_rl(struct request_list *rl,
+					 struct request_queue *q);
+/**
+ * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
+ *
+ * Should be used under queue_lock.
+ */
+#define blk_queue_for_each_rl(rl, q)	\
+	for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
+
+static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
+{
+	int ret;
+
+	ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
+	if (ret)
+		return ret;
+
+	atomic64_set(&stat->aux_cnt, 0);
+	return 0;
+}
+
+static inline void blkg_stat_exit(struct blkg_stat *stat)
+{
+	percpu_counter_destroy(&stat->cpu_cnt);
+}
+
+/**
+ * blkg_stat_add - add a value to a blkg_stat
+ * @stat: target blkg_stat
+ * @val: value to add
+ *
+ * Add @val to @stat.  The caller must ensure that IRQ on the same CPU
+ * don't re-enter this function for the same counter.
+ */
+static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
+{
+	__percpu_counter_add(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
+}
+
+/**
+ * blkg_stat_read - read the current value of a blkg_stat
+ * @stat: blkg_stat to read
+ */
+static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
+{
+	return percpu_counter_sum_positive(&stat->cpu_cnt);
+}
+
+/**
+ * blkg_stat_reset - reset a blkg_stat
+ * @stat: blkg_stat to reset
+ */
+static inline void blkg_stat_reset(struct blkg_stat *stat)
+{
+	percpu_counter_set(&stat->cpu_cnt, 0);
+	atomic64_set(&stat->aux_cnt, 0);
+}
+
+/**
+ * blkg_stat_add_aux - add a blkg_stat into another's aux count
+ * @to: the destination blkg_stat
+ * @from: the source
+ *
+ * Add @from's count including the aux one to @to's aux count.
+ */
+static inline void blkg_stat_add_aux(struct blkg_stat *to,
+				     struct blkg_stat *from)
+{
+	atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
+		     &to->aux_cnt);
+}
+
+static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
+{
+	int i, ret;
+
+	for (i = 0; i < BLKG_RWSTAT_NR; i++) {
+		ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
+		if (ret) {
+			while (--i >= 0)
+				percpu_counter_destroy(&rwstat->cpu_cnt[i]);
+			return ret;
+		}
+		atomic64_set(&rwstat->aux_cnt[i], 0);
+	}
+	return 0;
+}
+
+static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
+{
+	int i;
+
+	for (i = 0; i < BLKG_RWSTAT_NR; i++)
+		percpu_counter_destroy(&rwstat->cpu_cnt[i]);
+}
+
+/**
+ * blkg_rwstat_add - add a value to a blkg_rwstat
+ * @rwstat: target blkg_rwstat
+ * @rw: mask of REQ_{WRITE|SYNC}
+ * @val: value to add
+ *
+ * Add @val to @rwstat.  The counters are chosen according to @rw.  The
+ * caller is responsible for synchronizing calls to this function.
+ */
+static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
+				   int rw, uint64_t val)
+{
+	struct percpu_counter *cnt;
+
+	if (rw & REQ_WRITE)
+		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
+	else
+		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
+
+	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
+
+	if (rw & REQ_SYNC)
+		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
+	else
+		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
+
+	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
+}
+
+/**
+ * blkg_rwstat_read - read the current values of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Read the current snapshot of @rwstat and return it in the aux counts.
+ */
+static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
+{
+	struct blkg_rwstat result;
+	int i;
+
+	for (i = 0; i < BLKG_RWSTAT_NR; i++)
+		atomic64_set(&result.aux_cnt[i],
+			     percpu_counter_sum_positive(&rwstat->cpu_cnt[i]));
+	return result;
+}
+
+/**
+ * blkg_rwstat_total - read the total count of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Return the total count of @rwstat regardless of the IO direction.  This
+ * function can be called without synchronization and takes care of u64
+ * atomicity.
+ */
+static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
+{
+	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
+
+	return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
+		atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
+}
+
+/**
+ * blkg_rwstat_reset - reset a blkg_rwstat
+ * @rwstat: blkg_rwstat to reset
+ */
+static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
+{
+	int i;
+
+	for (i = 0; i < BLKG_RWSTAT_NR; i++) {
+		percpu_counter_set(&rwstat->cpu_cnt[i], 0);
+		atomic64_set(&rwstat->aux_cnt[i], 0);
+	}
+}
+
+/**
+ * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
+ * @to: the destination blkg_rwstat
+ * @from: the source
+ *
+ * Add @from's count including the aux one to @to's aux count.
+ */
+static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
+				       struct blkg_rwstat *from)
+{
+	struct blkg_rwstat v = blkg_rwstat_read(from);
+	int i;
+
+	for (i = 0; i < BLKG_RWSTAT_NR; i++)
+		atomic64_add(atomic64_read(&v.aux_cnt[i]) +
+			     atomic64_read(&from->aux_cnt[i]),
+			     &to->aux_cnt[i]);
+}
+
+#ifdef CONFIG_BLK_DEV_THROTTLING
+extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
+			   struct bio *bio);
+#else
+static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
+				  struct bio *bio) { return false; }
+#endif
+
+static inline bool blkcg_bio_issue_check(struct request_queue *q,
+					 struct bio *bio)
+{
+	struct blkcg *blkcg;
+	struct blkcg_gq *blkg;
+	bool throtl = false;
+
+	rcu_read_lock();
+	blkcg = bio_blkcg(bio);
+
+	blkg = blkg_lookup(blkcg, q);
+	if (unlikely(!blkg)) {
+		spin_lock_irq(q->queue_lock);
+		blkg = blkg_lookup_create(blkcg, q);
+		if (IS_ERR(blkg))
+			blkg = NULL;
+		spin_unlock_irq(q->queue_lock);
+	}
+
+	throtl = blk_throtl_bio(q, blkg, bio);
+
+	if (!throtl) {
+		blkg = blkg ?: q->root_blkg;
+		blkg_rwstat_add(&blkg->stat_bytes, bio->bi_rw,
+				bio->bi_iter.bi_size);
+		blkg_rwstat_add(&blkg->stat_ios, bio->bi_rw, 1);
+	}
+
+	rcu_read_unlock();
+	return !throtl;
+}
+
+#else	/* CONFIG_BLK_CGROUP */
+
+struct blkcg {
+};
+
+struct blkg_policy_data {
+};
+
+struct blkcg_policy_data {
+};
+
+struct blkcg_gq {
+};
+
+struct blkcg_policy {
+};
+
+#define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
+
+static inline struct cgroup_subsys_state *
+task_get_blkcg_css(struct task_struct *task)
+{
+	return NULL;
+}
+
+#ifdef CONFIG_BLOCK
+
+static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
+static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
+static inline void blkcg_drain_queue(struct request_queue *q) { }
+static inline void blkcg_exit_queue(struct request_queue *q) { }
+static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
+static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
+static inline int blkcg_activate_policy(struct request_queue *q,
+					const struct blkcg_policy *pol) { return 0; }
+static inline void blkcg_deactivate_policy(struct request_queue *q,
+					   const struct blkcg_policy *pol) { }
+
+static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
+
+static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
+						  struct blkcg_policy *pol) { return NULL; }
+static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
+static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
+static inline void blkg_get(struct blkcg_gq *blkg) { }
+static inline void blkg_put(struct blkcg_gq *blkg) { }
+
+static inline struct request_list *blk_get_rl(struct request_queue *q,
+					      struct bio *bio) { return &q->root_rl; }
+static inline void blk_put_rl(struct request_list *rl) { }
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
+static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
+
+static inline bool blkcg_bio_issue_check(struct request_queue *q,
+					 struct bio *bio) { return true; }
+
+#define blk_queue_for_each_rl(rl, q)	\
+	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
+
+#endif	/* CONFIG_BLOCK */
+#endif	/* CONFIG_BLK_CGROUP */
+#endif	/* _BLK_CGROUP_H */