[mirror_ubuntu-bionic-kernel.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 blkio_cgroup {
	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 blkio_cgroup */
	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 blkio_group *blkg;

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

struct blkio_group {
	/* Pointer to the associated request_queue */
	struct request_queue *q;
	struct list_head q_node;
	struct hlist_node blkcg_node;
	struct blkio_cgroup *blkcg;
	/* Store cgroup path */
	char path[128];
	/* reference count */
	int refcnt;

	struct blkg_policy_data *pd[BLKCG_MAX_POLS];

	struct rcu_head rcu_head;
};

typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);

struct blkio_policy_ops {
	blkio_init_group_fn *blkio_init_group_fn;
	blkio_exit_group_fn *blkio_exit_group_fn;
	blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
};

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

extern int blkcg_init_queue(struct request_queue *q);
extern void blkcg_drain_queue(struct request_queue *q);
extern void blkcg_exit_queue(struct request_queue *q);

/* Blkio controller policy registration */
extern int blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
extern void update_root_blkg_pd(struct request_queue *q,
				const struct blkio_policy_type *pol);

void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
		       u64 (*prfill)(struct seq_file *, void *, int),
		       const struct blkio_policy_type *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 blkio_group	*blkg;
	u64			v;
};

int blkg_conf_prep(struct blkio_cgroup *blkcg, 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 blkio_group *blkg,
			      struct blkio_policy_type *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 blkio_group *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;
}

static inline char *blkg_path(struct blkio_group *blkg)
{
	return blkg->path;
}

/**
 * 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 blkio_group *blkg)
{
	lockdep_assert_held(blkg->q->queue_lock);
	WARN_ON_ONCE(!blkg->refcnt);
	blkg->refcnt++;
}

void __blkg_release(struct blkio_group *blkg);

/**
 * blkg_put - put a blkg reference
 * @blkg: blkg to put
 *
 * The caller should be holding queue_lock.
 */
static inline void blkg_put(struct blkio_group *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 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

struct blkio_group {
};

struct blkio_policy_type {
};

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 blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
static inline void blkg_destroy_all(struct request_queue *q,
				    bool destory_root) { }
static inline void update_root_blkg_pd(struct request_queue *q,
				       const struct blkio_policy_type *pol) { }

static inline void *blkg_to_pdata(struct blkio_group *blkg,
				struct blkio_policy_type *pol) { return NULL; }
static inline struct blkio_group *pdata_to_blkg(void *pdata,
				struct blkio_policy_type *pol) { return NULL; }
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
static inline void blkg_get(struct blkio_group *blkg) { }
static inline void blkg_put(struct blkio_group *blkg) { }

#endif

#ifdef CONFIG_BLK_CGROUP
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
				       struct request_queue *q);
struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
				       struct request_queue *q,
				       bool for_root);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
static inline struct blkio_cgroup *
bio_blkio_cgroup(struct bio *bio) { return NULL; }

static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
					      void *key) { return NULL; }
#endif
#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
31e4c28d VG	40	struct blkio_cgroup {
31e4c28d VG	41	struct cgroup_subsys_state css;
31e4c28d VG	42	spinlock_t lock;
31e4c28d VG	43	struct hlist_head blkg_list;
9a9e8a26 TH	44
	45	/* for policies to test whether associated blkcg has changed */
	46	uint64_t id;
3381cb8d TH	47
	48	/* TODO: per-policy storage in blkio_cgroup */
	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 */
	65	struct blkio_group *blkg;
	66
	67	/* pol->pdata_size bytes of private data used by policy impl */
	68	char pdata[] __aligned(__alignof__(unsigned long long));
	69	};
	70
31e4c28d	71	struct blkio_group {
c875f4d0 TH	72	/* Pointer to the associated request_queue */
c875f4d0 TH	73	struct request_queue *q;
e8989fae	74	struct list_head q_node;
31e4c28d	75	struct hlist_node blkcg_node;
7ee9c562	76	struct blkio_cgroup *blkcg;
2868ef7b VG	77	/* Store cgroup path */
2868ef7b VG	78	char path[128];
1adaf3dd TH	79	/* reference count */
1adaf3dd TH	80	int refcnt;
22084190	81
8bd435b3	82	struct blkg_policy_data *pd[BLKCG_MAX_POLS];
1adaf3dd TH	83
1adaf3dd TH	84	struct rcu_head rcu_head;
31e4c28d VG	85	};
31e4c28d VG	86
0381411e	87	typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
9ade5ea4 TH	88	typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
9ade5ea4 TH	89	typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
3e252066 VG	90
3e252066 VG	91	struct blkio_policy_ops {
0381411e	92	blkio_init_group_fn *blkio_init_group_fn;
9ade5ea4 TH	93	blkio_exit_group_fn *blkio_exit_group_fn;
9ade5ea4 TH	94	blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
3e252066 VG	95	};
	96
	97	struct blkio_policy_type {
3e252066	98	struct blkio_policy_ops ops;
8bd435b3	99	int plid;
0381411e	100	size_t pdata_size; /* policy specific private data size */
44ea53de	101	struct cftype cftypes; / cgroup files for the policy */
3e252066 VG	102	};
3e252066 VG	103
5efd6113 TH	104	extern int blkcg_init_queue(struct request_queue *q);
	105	extern void blkcg_drain_queue(struct request_queue *q);
	106	extern void blkcg_exit_queue(struct request_queue *q);
	107
3e252066	108	/* Blkio controller policy registration */
8bd435b3	109	extern int blkio_policy_register(struct blkio_policy_type *);
3e252066	110	extern void blkio_policy_unregister(struct blkio_policy_type *);
e8989fae TH	111	extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
e8989fae TH	112	extern void update_root_blkg_pd(struct request_queue *q,
ec399347	113	const struct blkio_policy_type *pol);
3e252066	114
829fdb50	115	void blkcg_print_blkgs(struct seq_file sf, struct blkio_cgroup blkcg,
d366e7ec	116	u64 (prfill)(struct seq_file , void *, int),
ec399347 TH	117	const struct blkio_policy_type *pol, int data,
ec399347 TH	118	bool show_total);
d366e7ec TH	119	u64 __blkg_prfill_u64(struct seq_file sf, void pdata, u64 v);
d366e7ec TH	120	u64 __blkg_prfill_rwstat(struct seq_file sf, void pdata,
829fdb50	121	const struct blkg_rwstat *rwstat);
5bc4afb1 TH	122	u64 blkg_prfill_stat(struct seq_file sf, void pdata, int off);
5bc4afb1 TH	123	u64 blkg_prfill_rwstat(struct seq_file sf, void pdata, int off);
829fdb50 TH	124
	125	struct blkg_conf_ctx {
	126	struct gendisk *disk;
	127	struct blkio_group *blkg;
	128	u64 v;
	129	};
	130
	131	int blkg_conf_prep(struct blkio_cgroup blkcg, const char input,
	132	struct blkg_conf_ctx *ctx);
	133	void blkg_conf_finish(struct blkg_conf_ctx *ctx);
	134
	135
0381411e TH	136	/**
	137	* blkg_to_pdata - get policy private data
	138	* @blkg: blkg of interest
	139	* @pol: policy of interest
	140	*
	141	* Return pointer to private data associated with the @blkg-@pol pair.
	142	*/
	143	static inline void blkg_to_pdata(struct blkio_group blkg,
	144	struct blkio_policy_type *pol)
	145	{
549d3aa8	146	return blkg ? blkg->pd[pol->plid]->pdata : NULL;
0381411e TH	147	}
	148
	149	/**
	150	* pdata_to_blkg - get blkg associated with policy private data
	151	* @pdata: policy private data of interest
0381411e	152	*
aaec55a0	153	* @pdata is policy private data. Determine the blkg it's associated with.
0381411e	154	*/
aaec55a0	155	static inline struct blkio_group pdata_to_blkg(void pdata)
0381411e TH	156	{
	157	if (pdata) {
	158	struct blkg_policy_data *pd =
	159	container_of(pdata, struct blkg_policy_data, pdata);
	160	return pd->blkg;
	161	}
	162	return NULL;
	163	}
	164
afc24d49 VG	165	static inline char blkg_path(struct blkio_group blkg)
	166	{
	167	return blkg->path;
	168	}
	169
1adaf3dd TH	170	/**
	171	* blkg_get - get a blkg reference
	172	* @blkg: blkg to get
	173	*
	174	* The caller should be holding queue_lock and an existing reference.
	175	*/
	176	static inline void blkg_get(struct blkio_group *blkg)
	177	{
	178	lockdep_assert_held(blkg->q->queue_lock);
	179	WARN_ON_ONCE(!blkg->refcnt);
	180	blkg->refcnt++;
	181	}
	182
	183	void __blkg_release(struct blkio_group *blkg);
	184
	185	/**
	186	* blkg_put - put a blkg reference
	187	* @blkg: blkg to put
	188	*
	189	* The caller should be holding queue_lock.
	190	*/
	191	static inline void blkg_put(struct blkio_group *blkg)
	192	{
	193	lockdep_assert_held(blkg->q->queue_lock);
	194	WARN_ON_ONCE(blkg->refcnt <= 0);
	195	if (!--blkg->refcnt)
	196	__blkg_release(blkg);
	197	}
	198
edcb0722 TH	199	/**
	200	* blkg_stat_add - add a value to a blkg_stat
	201	* @stat: target blkg_stat
	202	* @val: value to add
	203	*
	204	* Add @val to @stat. The caller is responsible for synchronizing calls to
	205	* this function.
	206	*/
	207	static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
	208	{
	209	u64_stats_update_begin(&stat->syncp);
	210	stat->cnt += val;
	211	u64_stats_update_end(&stat->syncp);
	212	}
	213
	214	/**
	215	* blkg_stat_read - read the current value of a blkg_stat
	216	* @stat: blkg_stat to read
	217	*
	218	* Read the current value of @stat. This function can be called without
	219	* synchroniztion and takes care of u64 atomicity.
	220	*/
	221	static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
	222	{
	223	unsigned int start;
	224	uint64_t v;
	225
	226	do {
	227	start = u64_stats_fetch_begin(&stat->syncp);
	228	v = stat->cnt;
	229	} while (u64_stats_fetch_retry(&stat->syncp, start));
	230
	231	return v;
	232	}
	233
	234	/**
	235	* blkg_stat_reset - reset a blkg_stat
	236	* @stat: blkg_stat to reset
	237	*/
	238	static inline void blkg_stat_reset(struct blkg_stat *stat)
	239	{
	240	stat->cnt = 0;
	241	}
	242
	243	/**
	244	* blkg_rwstat_add - add a value to a blkg_rwstat
	245	* @rwstat: target blkg_rwstat
	246	* @rw: mask of REQ_{WRITE\|SYNC}
	247	* @val: value to add
	248	*
	249	* Add @val to @rwstat. The counters are chosen according to @rw. The
	250	* caller is responsible for synchronizing calls to this function.
	251	*/
	252	static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
	253	int rw, uint64_t val)
	254	{
	255	u64_stats_update_begin(&rwstat->syncp);
	256
	257	if (rw & REQ_WRITE)
	258	rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
	259	else
	260	rwstat->cnt[BLKG_RWSTAT_READ] += val;
	261	if (rw & REQ_SYNC)
	262	rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
263	else
264	rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
265
266	u64_stats_update_end(&rwstat->syncp);
267	}
268
269	/**
270	* blkg_rwstat_read - read the current values of a blkg_rwstat
271	* @rwstat: blkg_rwstat to read
272	*
273	* Read the current snapshot of @rwstat and return it as the return value.
274	* This function can be called without synchronization and takes care of
275	* u64 atomicity.
276	*/
277	static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
278	{
279	unsigned int start;
280	struct blkg_rwstat tmp;
281
282	do {
283	start = u64_stats_fetch_begin(&rwstat->syncp);
284	tmp = *rwstat;
285	} while (u64_stats_fetch_retry(&rwstat->syncp, start));
286
287	return tmp;
288	}
289
290	/**
291	* blkg_rwstat_sum - read the total count of a blkg_rwstat
292	* @rwstat: blkg_rwstat to read
293	*
294	* Return the total count of @rwstat regardless of the IO direction. This
295	* function can be called without synchronization and takes care of u64
296	* atomicity.
297	*/
298	static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
299	{
300	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
301
302	return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
303	}
304
305	/**
306	* blkg_rwstat_reset - reset a blkg_rwstat
307	* @rwstat: blkg_rwstat to reset
308	*/
309	static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
310	{
311	memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
312	}
313
2f5ea477 JA	314	#else
	315
	316	struct blkio_group {
	317	};
	318
3e252066 VG	319	struct blkio_policy_type {
	320	};
	321
5efd6113 TH	322	static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
	323	static inline void blkcg_drain_queue(struct request_queue *q) { }
	324	static inline void blkcg_exit_queue(struct request_queue *q) { }
8bd435b3	325	static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
3e252066	326	static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
03aa264a	327	static inline void blkg_destroy_all(struct request_queue *q,
03aa264a	328	bool destory_root) { }
e8989fae	329	static inline void update_root_blkg_pd(struct request_queue *q,
ec399347	330	const struct blkio_policy_type *pol) { }
3e252066	331
0381411e TH	332	static inline void blkg_to_pdata(struct blkio_group blkg,
	333	struct blkio_policy_type *pol) { return NULL; }
	334	static inline struct blkio_group pdata_to_blkg(void pdata,
	335	struct blkio_policy_type *pol) { return NULL; }
afc24d49	336	static inline char blkg_path(struct blkio_group blkg) { return NULL; }
1adaf3dd TH	337	static inline void blkg_get(struct blkio_group *blkg) { }
1adaf3dd TH	338	static inline void blkg_put(struct blkio_group *blkg) { }
afc24d49	339
2f5ea477 JA	340	#endif
2f5ea477 JA	341
32e380ae	342	#ifdef CONFIG_BLK_CGROUP
31e4c28d VG	343	extern struct blkio_cgroup blkio_root_cgroup;
31e4c28d VG	344	extern struct blkio_cgroup cgroup_to_blkio_cgroup(struct cgroup cgroup);
4f85cb96	345	extern struct blkio_cgroup bio_blkio_cgroup(struct bio bio);
cd1604fa	346	extern struct blkio_group blkg_lookup(struct blkio_cgroup blkcg,
e8989fae	347	struct request_queue *q);
cd1604fa TH	348	struct blkio_group blkg_lookup_create(struct blkio_cgroup blkcg,
cd1604fa TH	349	struct request_queue *q,
cd1604fa	350	bool for_root);
31e4c28d	351	#else
2f5ea477	352	struct cgroup;
31e4c28d VG	353	static inline struct blkio_cgroup *
31e4c28d VG	354	cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
70087dc3	355	static inline struct blkio_cgroup *
4f85cb96	356	bio_blkio_cgroup(struct bio *bio) { return NULL; }
31e4c28d	357
cd1604fa TH	358	static inline struct blkio_group blkg_lookup(struct blkio_cgroup blkcg,
cd1604fa TH	359	void *key) { return NULL; }
31e4c28d VG	360	#endif
31e4c28d VG	361	#endif /* _BLK_CGROUP_H */