[GitHub/LineageOS/android_kernel_motorola_exynos9610.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>

/* 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 {
	struct cgroup_subsys_state	css;
	spinlock_t			lock;
	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];
};

/* per-blkg per-policy data */
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;

	/* pol->pdata_size bytes of private data used by policy impl */
	char				pdata[] __aligned(__alignof__(unsigned long long));
};

/* 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;
	/* 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_ops {
	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;
};

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

extern struct blkcg blkcg_root;

struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup);
struct blkcg *bio_blkcg(struct bio *bio);
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 *, void *, int),
		       const struct blkcg_policy *pol, int data,
		       bool show_total);
u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
			 const struct blkg_rwstat *rwstat);
u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, 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);


/**
 * 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 void *blkg_to_pdata(struct blkcg_gq *blkg,
				  struct blkcg_policy *pol)
{
	return blkg ? blkg->pd[pol->plid]->pdata : NULL;
}

/**
 * pdata_to_blkg - get blkg associated with policy private data
 * @pdata: policy private data of interest
 *
 * @pdata is policy private data.  Determine the blkg it's associated with.
 */
static inline struct blkcg_gq *pdata_to_blkg(void *pdata)
{
	if (pdata) {
		struct blkg_policy_data *pd =
			container_of(pdata, struct blkg_policy_data, pdata);
		return pd->blkg;
	}
	return 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);
}

/**
 * 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_gq {
};

struct blkcg_policy {
};

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 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 void *blkg_to_pdata(struct blkcg_gq *blkg,
				  struct blkcg_policy *pol) { return NULL; }
static inline struct blkcg_gq *pdata_to_blkg(void *pdata,
				  struct blkcg_policy *pol) { 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) { }

#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>
31e4c28d	19
9355aede VG	20	/* Max limits for throttle policy */
	21	#define THROTL_IOPS_MAX UINT_MAX
	22
3381cb8d TH	23	/* CFQ specific, out here for blkcg->cfq_weight */
	24	#define CFQ_WEIGHT_MIN 10
	25	#define CFQ_WEIGHT_MAX 1000
	26	#define CFQ_WEIGHT_DEFAULT 500
	27
f48ec1d7 TH	28	#ifdef CONFIG_BLK_CGROUP
f48ec1d7 TH	29
edcb0722 TH	30	enum blkg_rwstat_type {
	31	BLKG_RWSTAT_READ,
	32	BLKG_RWSTAT_WRITE,
	33	BLKG_RWSTAT_SYNC,
	34	BLKG_RWSTAT_ASYNC,
	35
	36	BLKG_RWSTAT_NR,
	37	BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
303a3acb DS	38	};
303a3acb DS	39
3c798398	40	struct blkcg {
36558c8a TH	41	struct cgroup_subsys_state css;
	42	spinlock_t lock;
	43	struct hlist_head blkg_list;
9a9e8a26 TH	44
9a9e8a26 TH	45	/* for policies to test whether associated blkcg has changed */
36558c8a	46	uint64_t id;
3381cb8d	47
3c798398	48	/* TODO: per-policy storage in blkcg */
36558c8a	49	unsigned int cfq_weight; /* belongs to cfq */
31e4c28d VG	50	};
31e4c28d VG	51
edcb0722 TH	52	struct blkg_stat {
	53	struct u64_stats_sync syncp;
	54	uint64_t cnt;
	55	};
	56
	57	struct blkg_rwstat {
	58	struct u64_stats_sync syncp;
	59	uint64_t cnt[BLKG_RWSTAT_NR];
	60	};
	61
0381411e TH	62	/* per-blkg per-policy data */
	63	struct blkg_policy_data {
	64	/* the blkg this per-policy data belongs to */
3c798398	65	struct blkcg_gq *blkg;
0381411e	66
a2b1693b	67	/* used during policy activation */
36558c8a	68	struct list_head alloc_node;
a2b1693b	69
0381411e	70	/* pol->pdata_size bytes of private data used by policy impl */
36558c8a	71	char pdata[] __aligned(__alignof__(unsigned long long));
0381411e TH	72	};
0381411e TH	73
3c798398 TH	74	/* association between a blk cgroup and a request queue */
3c798398 TH	75	struct blkcg_gq {
c875f4d0	76	/* Pointer to the associated request_queue */
36558c8a TH	77	struct request_queue *q;
	78	struct list_head q_node;
	79	struct hlist_node blkcg_node;
3c798398	80	struct blkcg *blkcg;
1adaf3dd	81	/* reference count */
36558c8a	82	int refcnt;
22084190	83
36558c8a	84	struct blkg_policy_data *pd[BLKCG_MAX_POLS];
1adaf3dd	85
36558c8a	86	struct rcu_head rcu_head;
31e4c28d VG	87	};
31e4c28d VG	88
3c798398 TH	89	typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
	90	typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
	91	typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
3e252066	92
3c798398 TH	93	struct blkcg_policy_ops {
	94	blkcg_pol_init_pd_fn *pd_init_fn;
	95	blkcg_pol_exit_pd_fn *pd_exit_fn;
	96	blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
3e252066 VG	97	};
3e252066 VG	98
3c798398 TH	99	struct blkcg_policy {
3c798398 TH	100	struct blkcg_policy_ops ops;
36558c8a TH	101	int plid;
	102	/* policy specific private data size */
	103	size_t pdata_size;
	104	/* cgroup files for the policy */
	105	struct cftype *cftypes;
3e252066 VG	106	};
3e252066 VG	107
3c798398	108	extern struct blkcg blkcg_root;
36558c8a	109
3c798398 TH	110	struct blkcg cgroup_to_blkcg(struct cgroup cgroup);
	111	struct blkcg bio_blkcg(struct bio bio);
	112	struct blkcg_gq blkg_lookup(struct blkcg blkcg, struct request_queue *q);
	113	struct blkcg_gq blkg_lookup_create(struct blkcg blkcg,
	114	struct request_queue *q);
36558c8a TH	115	int blkcg_init_queue(struct request_queue *q);
	116	void blkcg_drain_queue(struct request_queue *q);
	117	void blkcg_exit_queue(struct request_queue *q);
5efd6113	118
3e252066	119	/* Blkio controller policy registration */
3c798398 TH	120	int blkcg_policy_register(struct blkcg_policy *pol);
3c798398 TH	121	void blkcg_policy_unregister(struct blkcg_policy *pol);
36558c8a	122	int blkcg_activate_policy(struct request_queue *q,
3c798398	123	const struct blkcg_policy *pol);
36558c8a	124	void blkcg_deactivate_policy(struct request_queue *q,
3c798398	125	const struct blkcg_policy *pol);
3e252066	126
3c798398	127	void blkcg_print_blkgs(struct seq_file sf, struct blkcg blkcg,
d366e7ec	128	u64 (prfill)(struct seq_file , void *, int),
3c798398	129	const struct blkcg_policy *pol, int data,
ec399347	130	bool show_total);
d366e7ec TH	131	u64 __blkg_prfill_u64(struct seq_file sf, void pdata, u64 v);
d366e7ec TH	132	u64 __blkg_prfill_rwstat(struct seq_file sf, void pdata,
829fdb50	133	const struct blkg_rwstat *rwstat);
5bc4afb1 TH	134	u64 blkg_prfill_stat(struct seq_file sf, void pdata, int off);
5bc4afb1 TH	135	u64 blkg_prfill_rwstat(struct seq_file sf, void pdata, int off);
829fdb50 TH	136
829fdb50 TH	137	struct blkg_conf_ctx {
36558c8a	138	struct gendisk *disk;
3c798398	139	struct blkcg_gq *blkg;
36558c8a	140	u64 v;
829fdb50 TH	141	};
829fdb50 TH	142
3c798398 TH	143	int blkg_conf_prep(struct blkcg blkcg, const struct blkcg_policy pol,
3c798398 TH	144	const char input, struct blkg_conf_ctx ctx);
829fdb50 TH	145	void blkg_conf_finish(struct blkg_conf_ctx *ctx);
	146
	147
0381411e TH	148	/**
	149	* blkg_to_pdata - get policy private data
	150	* @blkg: blkg of interest
	151	* @pol: policy of interest
	152	*
	153	* Return pointer to private data associated with the @blkg-@pol pair.
	154	*/
3c798398 TH	155	static inline void blkg_to_pdata(struct blkcg_gq blkg,
3c798398 TH	156	struct blkcg_policy *pol)
0381411e	157	{
549d3aa8	158	return blkg ? blkg->pd[pol->plid]->pdata : NULL;
0381411e TH	159	}
	160
	161	/**
	162	* pdata_to_blkg - get blkg associated with policy private data
	163	* @pdata: policy private data of interest
0381411e	164	*
aaec55a0	165	* @pdata is policy private data. Determine the blkg it's associated with.
0381411e	166	*/
3c798398	167	static inline struct blkcg_gq pdata_to_blkg(void pdata)
0381411e TH	168	{
	169	if (pdata) {
	170	struct blkg_policy_data *pd =
	171	container_of(pdata, struct blkg_policy_data, pdata);
	172	return pd->blkg;
	173	}
	174	return NULL;
	175	}
	176
54e7ed12 TH	177	/**
	178	* blkg_path - format cgroup path of blkg
	179	* @blkg: blkg of interest
	180	* @buf: target buffer
	181	* @buflen: target buffer length
	182	*
	183	* Format the path of the cgroup of @blkg into @buf.
	184	*/
3c798398	185	static inline int blkg_path(struct blkcg_gq blkg, char buf, int buflen)
afc24d49	186	{
54e7ed12 TH	187	int ret;
	188
	189	rcu_read_lock();
	190	ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
	191	rcu_read_unlock();
	192	if (ret)
	193	strncpy(buf, "<unavailable>", buflen);
	194	return ret;
afc24d49 VG	195	}
afc24d49 VG	196
1adaf3dd TH	197	/**
	198	* blkg_get - get a blkg reference
	199	* @blkg: blkg to get
	200	*
	201	* The caller should be holding queue_lock and an existing reference.
	202	*/
3c798398	203	static inline void blkg_get(struct blkcg_gq *blkg)
1adaf3dd TH	204	{
	205	lockdep_assert_held(blkg->q->queue_lock);
	206	WARN_ON_ONCE(!blkg->refcnt);
	207	blkg->refcnt++;
	208	}
	209
3c798398	210	void __blkg_release(struct blkcg_gq *blkg);
1adaf3dd TH	211
	212	/**
	213	* blkg_put - put a blkg reference
	214	* @blkg: blkg to put
	215	*
	216	* The caller should be holding queue_lock.
	217	*/
3c798398	218	static inline void blkg_put(struct blkcg_gq *blkg)
1adaf3dd TH	219	{
	220	lockdep_assert_held(blkg->q->queue_lock);
	221	WARN_ON_ONCE(blkg->refcnt <= 0);
	222	if (!--blkg->refcnt)
	223	__blkg_release(blkg);
	224	}
	225
edcb0722 TH	226	/**
	227	* blkg_stat_add - add a value to a blkg_stat
	228	* @stat: target blkg_stat
	229	* @val: value to add
	230	*
	231	* Add @val to @stat. The caller is responsible for synchronizing calls to
	232	* this function.
	233	*/
	234	static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
	235	{
	236	u64_stats_update_begin(&stat->syncp);
	237	stat->cnt += val;
	238	u64_stats_update_end(&stat->syncp);
	239	}
	240
	241	/**
	242	* blkg_stat_read - read the current value of a blkg_stat
	243	* @stat: blkg_stat to read
	244	*
	245	* Read the current value of @stat. This function can be called without
	246	* synchroniztion and takes care of u64 atomicity.
	247	*/
	248	static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
	249	{
	250	unsigned int start;
	251	uint64_t v;
	252
	253	do {
	254	start = u64_stats_fetch_begin(&stat->syncp);
	255	v = stat->cnt;
	256	} while (u64_stats_fetch_retry(&stat->syncp, start));
	257
	258	return v;
	259	}
	260
	261	/**
	262	* blkg_stat_reset - reset a blkg_stat
	263	* @stat: blkg_stat to reset
	264	*/
	265	static inline void blkg_stat_reset(struct blkg_stat *stat)
	266	{
	267	stat->cnt = 0;
	268	}
	269
	270	/**
	271	* blkg_rwstat_add - add a value to a blkg_rwstat
	272	* @rwstat: target blkg_rwstat
	273	* @rw: mask of REQ_{WRITE\|SYNC}
	274	* @val: value to add
	275	*
	276	* Add @val to @rwstat. The counters are chosen according to @rw. The
	277	* caller is responsible for synchronizing calls to this function.
	278	*/
	279	static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
	280	int rw, uint64_t val)
	281	{
	282	u64_stats_update_begin(&rwstat->syncp);
	283
	284	if (rw & REQ_WRITE)
	285	rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
	286	else
	287	rwstat->cnt[BLKG_RWSTAT_READ] += val;
	288	if (rw & REQ_SYNC)
	289	rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
290	else
291	rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
292
293	u64_stats_update_end(&rwstat->syncp);
294	}
295
296	/**
297	* blkg_rwstat_read - read the current values of a blkg_rwstat
298	* @rwstat: blkg_rwstat to read
299	*
300	* Read the current snapshot of @rwstat and return it as the return value.
301	* This function can be called without synchronization and takes care of
302	* u64 atomicity.
303	*/
c94bed89	304	static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
edcb0722 TH	305	{
	306	unsigned int start;
	307	struct blkg_rwstat tmp;
	308
	309	do {
	310	start = u64_stats_fetch_begin(&rwstat->syncp);
	311	tmp = *rwstat;
	312	} while (u64_stats_fetch_retry(&rwstat->syncp, start));
	313
	314	return tmp;
	315	}
	316
	317	/**
	318	* blkg_rwstat_sum - read the total count of a blkg_rwstat
	319	* @rwstat: blkg_rwstat to read
	320	*
	321	* Return the total count of @rwstat regardless of the IO direction. This
	322	* function can be called without synchronization and takes care of u64
	323	* atomicity.
	324	*/
	325	static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
	326	{
	327	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
	328
	329	return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
	330	}
	331
	332	/**
	333	* blkg_rwstat_reset - reset a blkg_rwstat
	334	* @rwstat: blkg_rwstat to reset
	335	*/
	336	static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
	337	{
	338	memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
	339	}
	340
36558c8a TH	341	#else /* CONFIG_BLK_CGROUP */
	342
	343	struct cgroup;
2f5ea477	344
3c798398	345	struct blkcg_gq {
2f5ea477 JA	346	};
2f5ea477 JA	347
3c798398	348	struct blkcg_policy {
3e252066 VG	349	};
3e252066 VG	350
3c798398 TH	351	static inline struct blkcg cgroup_to_blkcg(struct cgroup cgroup) { return NULL; }
	352	static inline struct blkcg bio_blkcg(struct bio bio) { return NULL; }
	353	static inline struct blkcg_gq blkg_lookup(struct blkcg blkcg, void *key) { return NULL; }
5efd6113 TH	354	static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
	355	static inline void blkcg_drain_queue(struct request_queue *q) { }
	356	static inline void blkcg_exit_queue(struct request_queue *q) { }
3c798398 TH	357	static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
3c798398 TH	358	static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
a2b1693b	359	static inline int blkcg_activate_policy(struct request_queue *q,
3c798398	360	const struct blkcg_policy *pol) { return 0; }
a2b1693b	361	static inline void blkcg_deactivate_policy(struct request_queue *q,
3c798398 TH	362	const struct blkcg_policy *pol) { }
	363
	364	static inline void blkg_to_pdata(struct blkcg_gq blkg,
	365	struct blkcg_policy *pol) { return NULL; }
	366	static inline struct blkcg_gq pdata_to_blkg(void pdata,
	367	struct blkcg_policy *pol) { return NULL; }
	368	static inline char blkg_path(struct blkcg_gq blkg) { return NULL; }
	369	static inline void blkg_get(struct blkcg_gq *blkg) { }
	370	static inline void blkg_put(struct blkcg_gq *blkg) { }
afc24d49	371
36558c8a TH	372	#endif /* CONFIG_BLK_CGROUP */
36558c8a TH	373	#endif /* _BLK_CGROUP_H */