[linux-2.6-block.git] / block / blk-cgroup.h

#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/u64_stats_sync.h>
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
#include <linux/blkdev.h>

/* Max limits for throttle policy */
#define THROTL_IOPS_MAX		UINT_MAX

/* CFQ specific, out here for blkcg->cfq_weight */
#define CFQ_WEIGHT_MIN		10
#define CFQ_WEIGHT_MAX		1000
#define CFQ_WEIGHT_DEFAULT	500

#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;

	/* for policies to test whether associated blkcg has changed */
	uint64_t			id;

	/* TODO: per-policy storage in blkcg */
	unsigned int			cfq_weight;	/* belongs to cfq */
};

struct blkg_stat {
	struct u64_stats_sync		syncp;
	uint64_t			cnt;
};

struct blkg_rwstat {
	struct u64_stats_sync		syncp;
	uint64_t			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 has its private
 * data on each blkg, the size of which is determined by
 * blkcg_policy->pd_size.  blkcg core allocates and frees such areas
 * together with blkg and invokes pd_init/exit_fn() methods.
 *
 * Such private data must embed struct blkg_policy_data (pd) at the
 * beginning and pd_size can't be smaller than pd.
 */
struct blkg_policy_data {
	/* the blkg this per-policy data belongs to */
	struct blkcg_gq			*blkg;

	/* used during policy activation */
	struct list_head		alloc_node;
};

/* 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;
	/* request allocation list for this blkcg-q pair */
	struct request_list		rl;
	/* reference count */
	int				refcnt;

	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];

	struct rcu_head			rcu_head;
};

typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);

struct blkcg_policy {
	int				plid;
	/* policy specific private data size */
	size_t				pd_size;
	/* cgroup files for the policy */
	struct cftype			*cftypes;

	/* operations */
	blkcg_pol_init_pd_fn		*pd_init_fn;
	blkcg_pol_exit_pd_fn		*pd_exit_fn;
	blkcg_pol_reset_pd_stats_fn	*pd_reset_stats_fn;
};

extern struct blkcg blkcg_root;

struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
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);

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);

struct blkg_conf_ctx {
	struct gendisk			*disk;
	struct blkcg_gq			*blkg;
	u64				v;
};

int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
		   const char *input, struct blkg_conf_ctx *ctx);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);


static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup)
{
	return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
			    struct blkcg, css);
}

static inline struct blkcg *task_blkcg(struct task_struct *tsk)
{
	return container_of(task_subsys_state(tsk, blkio_subsys_id),
			    struct blkcg, css);
}

static inline struct blkcg *bio_blkcg(struct bio *bio)
{
	if (bio && bio->bi_css)
		return container_of(bio->bi_css, struct blkcg, css);
	return task_blkcg(current);
}

/**
 * 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;
}

/**
 * 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;
}

/**
 * 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)
{
	int ret;

	rcu_read_lock();
	ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
	rcu_read_unlock();
	if (ret)
		strncpy(buf, "<unavailable>", buflen);
	return ret;
}

/**
 * blkg_get - get a blkg reference
 * @blkg: blkg to get
 *
 * The caller should be holding queue_lock and an existing reference.
 */
static inline void blkg_get(struct blkcg_gq *blkg)
{
	lockdep_assert_held(blkg->q->queue_lock);
	WARN_ON_ONCE(!blkg->refcnt);
	blkg->refcnt++;
}

void __blkg_release(struct blkcg_gq *blkg);

/**
 * blkg_put - put a blkg reference
 * @blkg: blkg to put
 *
 * The caller should be holding queue_lock.
 */
static inline void blkg_put(struct blkcg_gq *blkg)
{
	lockdep_assert_held(blkg->q->queue_lock);
	WARN_ON_ONCE(blkg->refcnt <= 0);
	if (!--blkg->refcnt)
		__blkg_release(blkg);
}

/**
 * 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_create(blkcg, q);
	if (unlikely(IS_ERR(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)
{
	/* root_rl may not have blkg set */
	if (rl->blkg && 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)))

/**
 * blkg_stat_add - add a value to a blkg_stat
 * @stat: target blkg_stat
 * @val: value to add
 *
 * Add @val to @stat.  The caller is responsible for synchronizing calls to
 * this function.
 */
static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
{
	u64_stats_update_begin(&stat->syncp);
	stat->cnt += val;
	u64_stats_update_end(&stat->syncp);
}

/**
 * blkg_stat_read - read the current value of a blkg_stat
 * @stat: blkg_stat to read
 *
 * Read the current value of @stat.  This function can be called without
 * synchroniztion and takes care of u64 atomicity.
 */
static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
{
	unsigned int start;
	uint64_t v;

	do {
		start = u64_stats_fetch_begin(&stat->syncp);
		v = stat->cnt;
	} while (u64_stats_fetch_retry(&stat->syncp, start));

	return v;
}

/**
 * blkg_stat_reset - reset a blkg_stat
 * @stat: blkg_stat to reset
 */
static inline void blkg_stat_reset(struct blkg_stat *stat)
{
	stat->cnt = 0;
}

/**
 * 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)
{
	u64_stats_update_begin(&rwstat->syncp);

	if (rw & REQ_WRITE)
		rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
	else
		rwstat->cnt[BLKG_RWSTAT_READ] += val;
	if (rw & REQ_SYNC)
		rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
	else
		rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;

	u64_stats_update_end(&rwstat->syncp);
}

/**
 * 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 as the return value.
 * This function can be called without synchronization and takes care of
 * u64 atomicity.
 */
static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
{
	unsigned int start;
	struct blkg_rwstat tmp;

	do {
		start = u64_stats_fetch_begin(&rwstat->syncp);
		tmp = *rwstat;
	} while (u64_stats_fetch_retry(&rwstat->syncp, start));

	return tmp;
}

/**
 * blkg_rwstat_sum - 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_sum(struct blkg_rwstat *rwstat)
{
	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);

	return tmp.cnt[BLKG_RWSTAT_READ] + tmp.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)
{
	memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
}

#else	/* CONFIG_BLK_CGROUP */

struct cgroup;
struct blkcg;

struct blkg_policy_data {
};

struct blkcg_gq {
};

struct blkcg_policy {
};

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 *cgroup_to_blkcg(struct cgroup *cgroup) { 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 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; }

#define blk_queue_for_each_rl(rl, q)	\
	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)

#endif	/* CONFIG_BLK_CGROUP */
#endif	/* _BLK_CGROUP_H */
Commit	Line	Data
31e4c28d VG	1	#ifndef _BLK_CGROUP_H
	2	#define _BLK_CGROUP_H
	3	/*
	4	* Common Block IO controller cgroup interface
	5	*
	6	* Based on ideas and code from CFQ, CFS and BFQ:
	7	* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
	8	*
	9	* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
	10	* Paolo Valente <paolo.valente@unimore.it>
	11	*
	12	* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
	13	* Nauman Rafique <nauman@google.com>
	14	*/
	15
	16	#include <linux/cgroup.h>
575969a0	17	#include <linux/u64_stats_sync.h>
829fdb50	18	#include <linux/seq_file.h>
a637120e	19	#include <linux/radix-tree.h>
a051661c	20	#include <linux/blkdev.h>
31e4c28d	21
9355aede VG	22	/* Max limits for throttle policy */
	23	#define THROTL_IOPS_MAX UINT_MAX
	24
3381cb8d TH	25	/* CFQ specific, out here for blkcg->cfq_weight */
	26	#define CFQ_WEIGHT_MIN 10
	27	#define CFQ_WEIGHT_MAX 1000
	28	#define CFQ_WEIGHT_DEFAULT 500
	29
f48ec1d7 TH	30	#ifdef CONFIG_BLK_CGROUP
f48ec1d7 TH	31
edcb0722 TH	32	enum blkg_rwstat_type {
	33	BLKG_RWSTAT_READ,
	34	BLKG_RWSTAT_WRITE,
	35	BLKG_RWSTAT_SYNC,
	36	BLKG_RWSTAT_ASYNC,
	37
	38	BLKG_RWSTAT_NR,
	39	BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
303a3acb DS	40	};
303a3acb DS	41
a637120e TH	42	struct blkcg_gq;
a637120e TH	43
3c798398	44	struct blkcg {
36558c8a TH	45	struct cgroup_subsys_state css;
36558c8a TH	46	spinlock_t lock;
a637120e TH	47
	48	struct radix_tree_root blkg_tree;
	49	struct blkcg_gq *blkg_hint;
36558c8a	50	struct hlist_head blkg_list;
9a9e8a26 TH	51
9a9e8a26 TH	52	/* for policies to test whether associated blkcg has changed */
36558c8a	53	uint64_t id;
3381cb8d	54
3c798398	55	/* TODO: per-policy storage in blkcg */
36558c8a	56	unsigned int cfq_weight; /* belongs to cfq */
31e4c28d VG	57	};
31e4c28d VG	58
edcb0722 TH	59	struct blkg_stat {
	60	struct u64_stats_sync syncp;
	61	uint64_t cnt;
	62	};
	63
	64	struct blkg_rwstat {
	65	struct u64_stats_sync syncp;
	66	uint64_t cnt[BLKG_RWSTAT_NR];
	67	};
	68
f95a04af TH	69	/*
	70	* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
	71	* request_queue (q). This is used by blkcg policies which need to track
	72	* information per blkcg - q pair.
	73	*
	74	* There can be multiple active blkcg policies and each has its private
	75	* data on each blkg, the size of which is determined by
	76	* blkcg_policy->pd_size. blkcg core allocates and frees such areas
	77	* together with blkg and invokes pd_init/exit_fn() methods.
	78	*
	79	* Such private data must embed struct blkg_policy_data (pd) at the
	80	* beginning and pd_size can't be smaller than pd.
	81	*/
0381411e TH	82	struct blkg_policy_data {
0381411e TH	83	/* the blkg this per-policy data belongs to */
3c798398	84	struct blkcg_gq *blkg;
0381411e	85
a2b1693b	86	/* used during policy activation */
36558c8a	87	struct list_head alloc_node;
0381411e TH	88	};
0381411e TH	89
3c798398 TH	90	/* association between a blk cgroup and a request queue */
3c798398 TH	91	struct blkcg_gq {
c875f4d0	92	/* Pointer to the associated request_queue */
36558c8a TH	93	struct request_queue *q;
	94	struct list_head q_node;
	95	struct hlist_node blkcg_node;
3c798398	96	struct blkcg *blkcg;
a051661c TH	97	/* request allocation list for this blkcg-q pair */
a051661c TH	98	struct request_list rl;
1adaf3dd	99	/* reference count */
36558c8a	100	int refcnt;
22084190	101
36558c8a	102	struct blkg_policy_data *pd[BLKCG_MAX_POLS];
1adaf3dd	103
36558c8a	104	struct rcu_head rcu_head;
31e4c28d VG	105	};
31e4c28d VG	106
3c798398 TH	107	typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
	108	typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
	109	typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
3e252066	110
3c798398	111	struct blkcg_policy {
36558c8a TH	112	int plid;
36558c8a TH	113	/* policy specific private data size */
f95a04af	114	size_t pd_size;
36558c8a TH	115	/* cgroup files for the policy */
36558c8a TH	116	struct cftype *cftypes;
f9fcc2d3 TH	117
	118	/* operations */
	119	blkcg_pol_init_pd_fn *pd_init_fn;
	120	blkcg_pol_exit_pd_fn *pd_exit_fn;
	121	blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
3e252066 VG	122	};
3e252066 VG	123
3c798398	124	extern struct blkcg blkcg_root;
36558c8a	125
3c798398 TH	126	struct blkcg_gq blkg_lookup(struct blkcg blkcg, struct request_queue *q);
	127	struct blkcg_gq blkg_lookup_create(struct blkcg blkcg,
	128	struct request_queue *q);
36558c8a TH	129	int blkcg_init_queue(struct request_queue *q);
	130	void blkcg_drain_queue(struct request_queue *q);
	131	void blkcg_exit_queue(struct request_queue *q);
5efd6113	132
3e252066	133	/* Blkio controller policy registration */
3c798398 TH	134	int blkcg_policy_register(struct blkcg_policy *pol);
3c798398 TH	135	void blkcg_policy_unregister(struct blkcg_policy *pol);
36558c8a	136	int blkcg_activate_policy(struct request_queue *q,
3c798398	137	const struct blkcg_policy *pol);
36558c8a	138	void blkcg_deactivate_policy(struct request_queue *q,
3c798398	139	const struct blkcg_policy *pol);
3e252066	140
3c798398	141	void blkcg_print_blkgs(struct seq_file sf, struct blkcg blkcg,
f95a04af TH	142	u64 (prfill)(struct seq_file ,
f95a04af TH	143	struct blkg_policy_data *, int),
3c798398	144	const struct blkcg_policy *pol, int data,
ec399347	145	bool show_total);
f95a04af TH	146	u64 __blkg_prfill_u64(struct seq_file sf, struct blkg_policy_data pd, u64 v);
f95a04af TH	147	u64 __blkg_prfill_rwstat(struct seq_file sf, struct blkg_policy_data pd,
829fdb50	148	const struct blkg_rwstat *rwstat);
f95a04af TH	149	u64 blkg_prfill_stat(struct seq_file sf, struct blkg_policy_data pd, int off);
	150	u64 blkg_prfill_rwstat(struct seq_file sf, struct blkg_policy_data pd,
	151	int off);
829fdb50 TH	152
829fdb50 TH	153	struct blkg_conf_ctx {
36558c8a	154	struct gendisk *disk;
3c798398	155	struct blkcg_gq *blkg;
36558c8a	156	u64 v;
829fdb50 TH	157	};
829fdb50 TH	158
3c798398 TH	159	int blkg_conf_prep(struct blkcg blkcg, const struct blkcg_policy pol,
3c798398 TH	160	const char input, struct blkg_conf_ctx ctx);
829fdb50 TH	161	void blkg_conf_finish(struct blkg_conf_ctx *ctx);
	162
	163
b1208b56 TH	164	static inline struct blkcg cgroup_to_blkcg(struct cgroup cgroup)
	165	{
	166	return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
	167	struct blkcg, css);
	168	}
	169
	170	static inline struct blkcg task_blkcg(struct task_struct tsk)
	171	{
	172	return container_of(task_subsys_state(tsk, blkio_subsys_id),
	173	struct blkcg, css);
	174	}
	175
	176	static inline struct blkcg bio_blkcg(struct bio bio)
	177	{
	178	if (bio && bio->bi_css)
	179	return container_of(bio->bi_css, struct blkcg, css);
	180	return task_blkcg(current);
	181	}
	182
0381411e TH	183	/**
	184	* blkg_to_pdata - get policy private data
	185	* @blkg: blkg of interest
	186	* @pol: policy of interest
	187	*
	188	* Return pointer to private data associated with the @blkg-@pol pair.
	189	*/
f95a04af TH	190	static inline struct blkg_policy_data blkg_to_pd(struct blkcg_gq blkg,
f95a04af TH	191	struct blkcg_policy *pol)
0381411e	192	{
f95a04af	193	return blkg ? blkg->pd[pol->plid] : NULL;
0381411e TH	194	}
	195
	196	/**
	197	* pdata_to_blkg - get blkg associated with policy private data
f95a04af	198	* @pd: policy private data of interest
0381411e	199	*
f95a04af	200	* @pd is policy private data. Determine the blkg it's associated with.
0381411e	201	*/
f95a04af	202	static inline struct blkcg_gq pd_to_blkg(struct blkg_policy_data pd)
0381411e	203	{
f95a04af	204	return pd ? pd->blkg : NULL;
0381411e TH	205	}
0381411e TH	206
54e7ed12 TH	207	/**
	208	* blkg_path - format cgroup path of blkg
	209	* @blkg: blkg of interest
	210	* @buf: target buffer
	211	* @buflen: target buffer length
	212	*
	213	* Format the path of the cgroup of @blkg into @buf.
	214	*/
3c798398	215	static inline int blkg_path(struct blkcg_gq blkg, char buf, int buflen)
afc24d49	216	{
54e7ed12 TH	217	int ret;
	218
	219	rcu_read_lock();
	220	ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
	221	rcu_read_unlock();
	222	if (ret)
	223	strncpy(buf, "<unavailable>", buflen);
	224	return ret;
afc24d49 VG	225	}
afc24d49 VG	226
1adaf3dd TH	227	/**
	228	* blkg_get - get a blkg reference
	229	* @blkg: blkg to get
	230	*
	231	* The caller should be holding queue_lock and an existing reference.
	232	*/
3c798398	233	static inline void blkg_get(struct blkcg_gq *blkg)
1adaf3dd TH	234	{
	235	lockdep_assert_held(blkg->q->queue_lock);
	236	WARN_ON_ONCE(!blkg->refcnt);
	237	blkg->refcnt++;
	238	}
	239
3c798398	240	void __blkg_release(struct blkcg_gq *blkg);
1adaf3dd TH	241
	242	/**
	243	* blkg_put - put a blkg reference
	244	* @blkg: blkg to put
	245	*
	246	* The caller should be holding queue_lock.
	247	*/
3c798398	248	static inline void blkg_put(struct blkcg_gq *blkg)
1adaf3dd TH	249	{
	250	lockdep_assert_held(blkg->q->queue_lock);
	251	WARN_ON_ONCE(blkg->refcnt <= 0);
	252	if (!--blkg->refcnt)
	253	__blkg_release(blkg);
	254	}
	255
a051661c TH	256	/**
	257	* blk_get_rl - get request_list to use
	258	* @q: request_queue of interest
	259	* @bio: bio which will be attached to the allocated request (may be %NULL)
	260	*
	261	* The caller wants to allocate a request from @q to use for @bio. Find
	262	* the request_list to use and obtain a reference on it. Should be called
	263	* under queue_lock. This function is guaranteed to return non-%NULL
	264	* request_list.
	265	*/
	266	static inline struct request_list blk_get_rl(struct request_queue q,
	267	struct bio *bio)
	268	{
	269	struct blkcg *blkcg;
	270	struct blkcg_gq *blkg;
	271
	272	rcu_read_lock();
	273
	274	blkcg = bio_blkcg(bio);
	275
	276	/* bypass blkg lookup and use @q->root_rl directly for root */
	277	if (blkcg == &blkcg_root)
	278	goto root_rl;
	279
	280	/*
	281	* Try to use blkg->rl. blkg lookup may fail under memory pressure
	282	* or if either the blkcg or queue is going away. Fall back to
	283	* root_rl in such cases.
	284	*/
	285	blkg = blkg_lookup_create(blkcg, q);
	286	if (unlikely(IS_ERR(blkg)))
	287	goto root_rl;
	288
	289	blkg_get(blkg);
	290	rcu_read_unlock();
	291	return &blkg->rl;
	292	root_rl:
	293	rcu_read_unlock();
	294	return &q->root_rl;
	295	}
	296
	297	/**
	298	* blk_put_rl - put request_list
	299	* @rl: request_list to put
	300	*
	301	* Put the reference acquired by blk_get_rl(). Should be called under
	302	* queue_lock.
	303	*/
	304	static inline void blk_put_rl(struct request_list *rl)
	305	{
	306	/* root_rl may not have blkg set */
	307	if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
	308	blkg_put(rl->blkg);
	309	}
	310
	311	/**
	312	* blk_rq_set_rl - associate a request with a request_list
	313	* @rq: request of interest
	314	* @rl: target request_list
	315	*
	316	* Associate @rq with @rl so that accounting and freeing can know the
	317	* request_list @rq came from.
	318	*/
	319	static inline void blk_rq_set_rl(struct request rq, struct request_list rl)
320	{
321	rq->rl = rl;
322	}
323
324	/**
325	* blk_rq_rl - return the request_list a request came from
326	* @rq: request of interest
327	*
328	* Return the request_list @rq is allocated from.
329	*/
330	static inline struct request_list blk_rq_rl(struct request rq)
331	{
332	return rq->rl;
333	}
334
335	struct request_list __blk_queue_next_rl(struct request_list rl,
336	struct request_queue *q);
337	/**
338	* blk_queue_for_each_rl - iterate through all request_lists of a request_queue
339	*
340	* Should be used under queue_lock.
341	*/
342	#define blk_queue_for_each_rl(rl, q) \
343	for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
344
edcb0722 TH	345	/**
	346	* blkg_stat_add - add a value to a blkg_stat
	347	* @stat: target blkg_stat
	348	* @val: value to add
	349	*
	350	* Add @val to @stat. The caller is responsible for synchronizing calls to
	351	* this function.
	352	*/
	353	static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
	354	{
	355	u64_stats_update_begin(&stat->syncp);
	356	stat->cnt += val;
	357	u64_stats_update_end(&stat->syncp);
	358	}
	359
	360	/**
	361	* blkg_stat_read - read the current value of a blkg_stat
	362	* @stat: blkg_stat to read
	363	*
	364	* Read the current value of @stat. This function can be called without
	365	* synchroniztion and takes care of u64 atomicity.
	366	*/
	367	static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
	368	{
	369	unsigned int start;
	370	uint64_t v;
	371
	372	do {
	373	start = u64_stats_fetch_begin(&stat->syncp);
	374	v = stat->cnt;
	375	} while (u64_stats_fetch_retry(&stat->syncp, start));
	376
	377	return v;
	378	}
	379
	380	/**
	381	* blkg_stat_reset - reset a blkg_stat
	382	* @stat: blkg_stat to reset
	383	*/
	384	static inline void blkg_stat_reset(struct blkg_stat *stat)
	385	{
	386	stat->cnt = 0;
	387	}
	388
	389	/**
	390	* blkg_rwstat_add - add a value to a blkg_rwstat
	391	* @rwstat: target blkg_rwstat
	392	* @rw: mask of REQ_{WRITE\|SYNC}
	393	* @val: value to add
	394	*
	395	* Add @val to @rwstat. The counters are chosen according to @rw. The
	396	* caller is responsible for synchronizing calls to this function.
	397	*/
	398	static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
	399	int rw, uint64_t val)
	400	{
	401	u64_stats_update_begin(&rwstat->syncp);
	402
	403	if (rw & REQ_WRITE)
	404	rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
	405	else
	406	rwstat->cnt[BLKG_RWSTAT_READ] += val;
	407	if (rw & REQ_SYNC)
	408	rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
409	else
410	rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
411
412	u64_stats_update_end(&rwstat->syncp);
413	}
414
415	/**
416	* blkg_rwstat_read - read the current values of a blkg_rwstat
417	* @rwstat: blkg_rwstat to read
418	*
419	* Read the current snapshot of @rwstat and return it as the return value.
420	* This function can be called without synchronization and takes care of
421	* u64 atomicity.
422	*/
c94bed89	423	static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
edcb0722 TH	424	{
	425	unsigned int start;
	426	struct blkg_rwstat tmp;
	427
	428	do {
	429	start = u64_stats_fetch_begin(&rwstat->syncp);
	430	tmp = *rwstat;
	431	} while (u64_stats_fetch_retry(&rwstat->syncp, start));
	432
	433	return tmp;
	434	}
	435
	436	/**
	437	* blkg_rwstat_sum - read the total count of a blkg_rwstat
	438	* @rwstat: blkg_rwstat to read
	439	*
	440	* Return the total count of @rwstat regardless of the IO direction. This
	441	* function can be called without synchronization and takes care of u64
	442	* atomicity.
	443	*/
	444	static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
	445	{
	446	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
	447
	448	return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
	449	}
	450
	451	/**
	452	* blkg_rwstat_reset - reset a blkg_rwstat
	453	* @rwstat: blkg_rwstat to reset
	454	*/
	455	static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
	456	{
	457	memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
	458	}
	459
36558c8a TH	460	#else /* CONFIG_BLK_CGROUP */
	461
	462	struct cgroup;
b1208b56	463	struct blkcg;
2f5ea477	464
f95a04af TH	465	struct blkg_policy_data {
	466	};
	467
3c798398	468	struct blkcg_gq {
2f5ea477 JA	469	};
2f5ea477 JA	470
3c798398	471	struct blkcg_policy {
3e252066 VG	472	};
3e252066 VG	473
3c798398	474	static inline struct blkcg_gq blkg_lookup(struct blkcg blkcg, void *key) { return NULL; }
5efd6113 TH	475	static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
	476	static inline void blkcg_drain_queue(struct request_queue *q) { }
	477	static inline void blkcg_exit_queue(struct request_queue *q) { }
3c798398 TH	478	static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
3c798398 TH	479	static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
a2b1693b	480	static inline int blkcg_activate_policy(struct request_queue *q,
3c798398	481	const struct blkcg_policy *pol) { return 0; }
a2b1693b	482	static inline void blkcg_deactivate_policy(struct request_queue *q,
3c798398 TH	483	const struct blkcg_policy *pol) { }
3c798398 TH	484
b1208b56 TH	485	static inline struct blkcg cgroup_to_blkcg(struct cgroup cgroup) { return NULL; }
b1208b56 TH	486	static inline struct blkcg bio_blkcg(struct bio bio) { return NULL; }
a051661c	487
f95a04af TH	488	static inline struct blkg_policy_data blkg_to_pd(struct blkcg_gq blkg,
	489	struct blkcg_policy *pol) { return NULL; }
	490	static inline struct blkcg_gq pd_to_blkg(struct blkg_policy_data pd) { return NULL; }
3c798398 TH	491	static inline char blkg_path(struct blkcg_gq blkg) { return NULL; }
	492	static inline void blkg_get(struct blkcg_gq *blkg) { }
	493	static inline void blkg_put(struct blkcg_gq *blkg) { }
afc24d49	494
a051661c TH	495	static inline struct request_list blk_get_rl(struct request_queue q,
	496	struct bio *bio) { return &q->root_rl; }
	497	static inline void blk_put_rl(struct request_list *rl) { }
	498	static inline void blk_rq_set_rl(struct request rq, struct request_list rl) { }
	499	static inline struct request_list blk_rq_rl(struct request rq) { return &rq->q->root_rl; }
	500
	501	#define blk_queue_for_each_rl(rl, q) \
	502	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
	503
36558c8a TH	504	#endif /* CONFIG_BLK_CGROUP */
36558c8a TH	505	#endif /* _BLK_CGROUP_H */