1 files changed, 17 insertions, 692 deletions

diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index b4de2010fba5..dd5841a42c33 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -14,713 +14,38 @@
  * 	              Nauman Rafique <nauman@google.com>
  */
 
-#include <linux/cgroup.h>
-#include <linux/percpu.h>
-#include <linux/percpu_counter.h>
-#include <linux/u64_stats_sync.h>
-#include <linux/seq_file.h>
-#include <linux/radix-tree.h>
-#include <linux/blkdev.h>
-#include <linux/atomic.h>
-#include <linux/kthread.h>
-#include <linux/fs.h>
+#include <linux/types.h>
 
-/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
-#define BLKG_STAT_CPU_BATCH	(INT_MAX / 2)
+struct bio;
+struct cgroup_subsys_state;
+struct gendisk;
 
-/* Max limits for throttle policy */
-#define THROTL_IOPS_MAX		UINT_MAX
 #define FC_APPID_LEN              129
 
-
 #ifdef CONFIG_BLK_CGROUP
-
-enum blkg_iostat_type {
-	BLKG_IOSTAT_READ,
-	BLKG_IOSTAT_WRITE,
-	BLKG_IOSTAT_DISCARD,
-
-	BLKG_IOSTAT_NR,
-};
-
-struct blkcg_gq;
-
-struct blkcg {
-	struct cgroup_subsys_state	css;
-	spinlock_t			lock;
-	refcount_t			online_pin;
-
-	struct radix_tree_root		blkg_tree;
-	struct blkcg_gq	__rcu		*blkg_hint;
-	struct hlist_head		blkg_list;
-
-	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];
-
-	struct list_head		all_blkcgs_node;
-#ifdef CONFIG_BLK_CGROUP_FC_APPID
-	char                            fc_app_id[FC_APPID_LEN];
-#endif
-#ifdef CONFIG_CGROUP_WRITEBACK
-	struct list_head		cgwb_list;
-#endif
-};
-
-struct blkg_iostat {
-	u64				bytes[BLKG_IOSTAT_NR];
-	u64				ios[BLKG_IOSTAT_NR];
-};
-
-struct blkg_iostat_set {
-	struct u64_stats_sync		sync;
-	struct blkg_iostat		cur;
-	struct blkg_iostat		last;
-};
-
-/*
- * 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;
-
-	/* all non-root blkcg_gq's are guaranteed to have access to parent */
-	struct blkcg_gq			*parent;
-
-	/* reference count */
-	struct percpu_ref		refcnt;
-
-	/* is this blkg online? protected by both blkcg and q locks */
-	bool				online;
-
-	struct blkg_iostat_set __percpu	*iostat_cpu;
-	struct blkg_iostat_set		iostat;
-
-	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];
-
-	spinlock_t			async_bio_lock;
-	struct bio_list			async_bios;
-	struct work_struct		async_bio_work;
-
-	atomic_t			use_delay;
-	atomic64_t			delay_nsec;
-	atomic64_t			delay_start;
-	u64				last_delay;
-	int				last_use;
-
-	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,
-				struct request_queue *q, struct blkcg *blkcg);
-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);
-typedef bool (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd,
-				struct seq_file *s);
-
-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;
-	blkcg_pol_stat_pd_fn		*pd_stat_fn;
-};
-
-extern struct blkcg blkcg_root;
 extern struct cgroup_subsys_state * const blkcg_root_css;
-extern bool blkcg_debug_stats;
-
-struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
-				      struct request_queue *q, bool update_hint);
-int blkcg_init_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);
-
-struct blkg_conf_ctx {
-	struct block_device		*bdev;
-	struct blkcg_gq			*blkg;
-	char				*body;
-};
-
-struct block_device *blkcg_conf_open_bdev(char **inputp);
-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);
-
-/**
- * blkcg_css - find the current css
- *
- * Find the css associated with either the kthread or the current task.
- * This may return a dying css, so it is up to the caller to use tryget logic
- * to confirm it is alive and well.
- */
-static inline struct cgroup_subsys_state *blkcg_css(void)
-{
-	struct cgroup_subsys_state *css;
-
-	css = kthread_blkcg();
-	if (css)
-		return css;
-	return task_css(current, io_cgrp_id);
-}
-
-static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
-{
-	return css ? container_of(css, struct blkcg, css) : NULL;
-}
-
-/**
- * __bio_blkcg - internal, inconsistent version to get blkcg
- *
- * DO NOT USE.
- * This function is inconsistent and consequently is dangerous to use.  The
- * first part of the function returns a blkcg where a reference is owned by the
- * bio.  This means it does not need to be rcu protected as it cannot go away
- * with the bio owning a reference to it.  However, the latter potentially gets
- * it from task_css().  This can race against task migration and the cgroup
- * dying.  It is also semantically different as it must be called rcu protected
- * and is susceptible to failure when trying to get a reference to it.
- * Therefore, it is not ok to assume that *_get() will always succeed on the
- * blkcg returned here.
- */
-static inline struct blkcg *__bio_blkcg(struct bio *bio)
-{
-	if (bio && bio->bi_blkg)
-		return bio->bi_blkg->blkcg;
-	return css_to_blkcg(blkcg_css());
-}
 
-/**
- * bio_blkcg - grab the blkcg associated with a bio
- * @bio: target bio
- *
- * This returns the blkcg associated with a bio, %NULL if not associated.
- * Callers are expected to either handle %NULL or know association has been
- * done prior to calling this.
- */
-static inline struct blkcg *bio_blkcg(struct bio *bio)
-{
-	if (bio && bio->bi_blkg)
-		return bio->bi_blkg->blkcg;
-	return NULL;
-}
-
-static inline bool blk_cgroup_congested(void)
-{
-	struct cgroup_subsys_state *css;
-	bool ret = false;
-
-	rcu_read_lock();
-	css = kthread_blkcg();
-	if (!css)
-		css = task_css(current, io_cgrp_id);
-	while (css) {
-		if (atomic_read(&css->cgroup->congestion_count)) {
-			ret = true;
-			break;
-		}
-		css = css->parent;
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
-/**
- * bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg
- * @return: true if this bio needs to be submitted with the root blkg context.
- *
- * In order to avoid priority inversions we sometimes need to issue a bio as if
- * it were attached to the root blkg, and then backcharge to the actual owning
- * blkg.  The idea is we do bio_blkcg() to look up the actual context for the
- * bio and attach the appropriate blkg to the bio.  Then we call this helper and
- * if it is true run with the root blkg for that queue and then do any
- * backcharging to the originating cgroup once the io is complete.
- */
-static inline bool bio_issue_as_root_blkg(struct bio *bio)
-{
-	return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0;
-}
-
-/**
- * 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.
- */
-static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
-					   struct request_queue *q)
-{
-	WARN_ON_ONCE(!rcu_read_lock_held());
-	return __blkg_lookup(blkcg, q, false);
-}
-
-/**
- * blk_queue_root_blkg - return blkg for the (blkcg_root, @q) pair
- * @q: request_queue of interest
- *
- * Lookup blkg for @q at the root level. See also blkg_lookup().
- */
-static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)
-{
-	return q->root_blkg;
-}
-
-/**
- * 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;
-}
-
-extern void blkcg_destroy_blkgs(struct blkcg *blkcg);
-
-/**
- * blkcg_pin_online - pin online state
- * @blkcg: blkcg of interest
- *
- * While pinned, a blkcg is kept online.  This is primarily used to
- * impedance-match blkg and cgwb lifetimes so that blkg doesn't go offline
- * while an associated cgwb is still active.
- */
-static inline void blkcg_pin_online(struct blkcg *blkcg)
-{
-	refcount_inc(&blkcg->online_pin);
-}
-
-/**
- * blkcg_unpin_online - unpin online state
- * @blkcg: blkcg of interest
- *
- * This is primarily used to impedance-match blkg and cgwb lifetimes so
- * that blkg doesn't go offline while an associated cgwb is still active.
- * When this count goes to zero, all active cgwbs have finished so the
- * blkcg can continue destruction by calling blkcg_destroy_blkgs().
- */
-static inline void blkcg_unpin_online(struct blkcg *blkcg)
-{
-	do {
-		if (!refcount_dec_and_test(&blkcg->online_pin))
-			break;
-		blkcg_destroy_blkgs(blkcg);
-		blkcg = blkcg_parent(blkcg);
-	} while (blkcg);
-}
-
-/**
- * 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)
-{
-	return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
-}
-
-/**
- * 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)
-{
-	percpu_ref_get(&blkg->refcnt);
-}
-
-/**
- * blkg_tryget - try and get a blkg reference
- * @blkg: blkg to get
- *
- * This is for use when doing an RCU lookup of the blkg.  We may be in the midst
- * of freeing this blkg, so we can only use it if the refcnt is not zero.
- */
-static inline bool blkg_tryget(struct blkcg_gq *blkg)
-{
-	return blkg && percpu_ref_tryget(&blkg->refcnt);
-}
-
-/**
- * blkg_put - put a blkg reference
- * @blkg: blkg to put
- */
-static inline void blkg_put(struct blkcg_gq *blkg)
-{
-	percpu_ref_put(&blkg->refcnt);
-}
-
-/**
- * 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)))
-
-bool __blkcg_punt_bio_submit(struct bio *bio);
-
-static inline bool blkcg_punt_bio_submit(struct bio *bio)
-{
-	if (bio->bi_opf & REQ_CGROUP_PUNT)
-		return __blkcg_punt_bio_submit(bio);
-	else
-		return false;
-}
-
-static inline void blkcg_bio_issue_init(struct bio *bio)
-{
-	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
-}
-
-static inline void blkcg_use_delay(struct blkcg_gq *blkg)
-{
-	if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
-		return;
-	if (atomic_add_return(1, &blkg->use_delay) == 1)
-		atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
-}
-
-static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
-{
-	int old = atomic_read(&blkg->use_delay);
-
-	if (WARN_ON_ONCE(old < 0))
-		return 0;
-	if (old == 0)
-		return 0;
-
-	/*
-	 * We do this song and dance because we can race with somebody else
-	 * adding or removing delay.  If we just did an atomic_dec we'd end up
-	 * negative and we'd already be in trouble.  We need to subtract 1 and
-	 * then check to see if we were the last delay so we can drop the
-	 * congestion count on the cgroup.
-	 */
-	while (old) {
-		int cur = atomic_cmpxchg(&blkg->use_delay, old, old - 1);
-		if (cur == old)
-			break;
-		old = cur;
-	}
-
-	if (old == 0)
-		return 0;
-	if (old == 1)
-		atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
-	return 1;
-}
-
-/**
- * blkcg_set_delay - Enable allocator delay mechanism with the specified delay amount
- * @blkg: target blkg
- * @delay: delay duration in nsecs
- *
- * When enabled with this function, the delay is not decayed and must be
- * explicitly cleared with blkcg_clear_delay(). Must not be mixed with
- * blkcg_[un]use_delay() and blkcg_add_delay() usages.
- */
-static inline void blkcg_set_delay(struct blkcg_gq *blkg, u64 delay)
-{
-	int old = atomic_read(&blkg->use_delay);
-
-	/* We only want 1 person setting the congestion count for this blkg. */
-	if (!old && atomic_cmpxchg(&blkg->use_delay, old, -1) == old)
-		atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
-
-	atomic64_set(&blkg->delay_nsec, delay);
-}
-
-/**
- * blkcg_clear_delay - Disable allocator delay mechanism
- * @blkg: target blkg
- *
- * Disable use_delay mechanism. See blkcg_set_delay().
- */
-static inline void blkcg_clear_delay(struct blkcg_gq *blkg)
-{
-	int old = atomic_read(&blkg->use_delay);
-
-	/* We only want 1 person clearing the congestion count for this blkg. */
-	if (old && atomic_cmpxchg(&blkg->use_delay, old, 0) == old)
-		atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
-}
-
-void blk_cgroup_bio_start(struct bio *bio);
-void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta);
-void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay);
+void blkcg_schedule_throttle(struct gendisk *disk, bool use_memdelay);
 void blkcg_maybe_throttle_current(void);
-#else	/* CONFIG_BLK_CGROUP */
-
-struct blkcg {
-};
-
-struct blkg_policy_data {
-};
-
-struct blkcg_policy_data {
-};
+bool blk_cgroup_congested(void);
+void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css);
+void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css);
+struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css);
+struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio);
 
-struct blkcg_gq {
-};
-
-struct blkcg_policy {
-};
+#else	/* CONFIG_BLK_CGROUP */
 
 #define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
 
 static inline void blkcg_maybe_throttle_current(void) { }
 static inline bool blk_cgroup_congested(void) { return false; }
-
-#ifdef CONFIG_BLOCK
-
-static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { }
-
-static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
-static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)
-{ return NULL; }
-static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
-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 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 bool blkcg_punt_bio_submit(struct bio *bio) { return false; }
-static inline void blkcg_bio_issue_init(struct bio *bio) { }
-static inline void blk_cgroup_bio_start(struct bio *bio) { }
-
-#define blk_queue_for_each_rl(rl, q)	\
-	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
-
-#endif	/* CONFIG_BLOCK */
-#endif	/* CONFIG_BLK_CGROUP */
-
-#ifdef CONFIG_BLK_CGROUP_FC_APPID
-/*
- * Sets the fc_app_id field associted to blkcg
- * @app_id: application identifier
- * @cgrp_id: cgroup id
- * @app_id_len: size of application identifier
- */
-static inline int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
-{
-	struct cgroup *cgrp;
-	struct cgroup_subsys_state *css;
-	struct blkcg *blkcg;
-	int ret  = 0;
-
-	if (app_id_len > FC_APPID_LEN)
-		return -EINVAL;
-
-	cgrp = cgroup_get_from_id(cgrp_id);
-	if (!cgrp)
-		return -ENOENT;
-	css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
-	if (!css) {
-		ret = -ENOENT;
-		goto out_cgrp_put;
-	}
-	blkcg = css_to_blkcg(css);
-	/*
-	 * There is a slight race condition on setting the appid.
-	 * Worst case an I/O may not find the right id.
-	 * This is no different from the I/O we let pass while obtaining
-	 * the vmid from the fabric.
-	 * Adding the overhead of a lock is not necessary.
-	 */
-	strlcpy(blkcg->fc_app_id, app_id, app_id_len);
-	css_put(css);
-out_cgrp_put:
-	cgroup_put(cgrp);
-	return ret;
-}
-
-/**
- * blkcg_get_fc_appid - get the fc app identifier associated with a bio
- * @bio: target bio
- *
- * On success return the fc_app_id, on failure return NULL
- */
-static inline char *blkcg_get_fc_appid(struct bio *bio)
+static inline struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)
 {
-	if (bio && bio->bi_blkg &&
-		(bio->bi_blkg->blkcg->fc_app_id[0] != '\0'))
-		return bio->bi_blkg->blkcg->fc_app_id;
 	return NULL;
 }
-#else
-static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len) { return -EINVAL; }
-static inline char *blkcg_get_fc_appid(struct bio *bio) { return NULL; }
-#endif /*CONFIG_BLK_CGROUP_FC_APPID*/
+#endif	/* CONFIG_BLK_CGROUP */
+
+int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len);
+char *blkcg_get_fc_appid(struct bio *bio);
+
 #endif	/* _BLK_CGROUP_H */