[deliverable/linux.git] / include / linux / iocontext.h

#ifndef IOCONTEXT_H
#define IOCONTEXT_H

#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>

enum {
	ICQ_IOPRIO_CHANGED,
	ICQ_CGROUP_CHANGED,
};

struct io_cq {
	struct request_queue	*q;
	struct io_context	*ioc;

	/*
	 * q_node and ioc_node link io_cq through icq_list of q and ioc
	 * respectively.  Both fields are unused once ioc_exit_icq() is
	 * called and shared with __rcu_icq_cache and __rcu_head which are
	 * used for RCU free of io_cq.
	 */
	union {
		struct list_head	q_node;
		struct kmem_cache	*__rcu_icq_cache;
	};
	union {
		struct hlist_node	ioc_node;
		struct rcu_head		__rcu_head;
	};

	unsigned long		changed;
};

/*
 * I/O subsystem state of the associated processes.  It is refcounted
 * and kmalloc'ed. These could be shared between processes.
 */
struct io_context {
	atomic_long_t refcount;
	atomic_t nr_tasks;

	/* all the fields below are protected by this lock */
	spinlock_t lock;

	unsigned short ioprio;

	/*
	 * For request batching
	 */
	int nr_batch_requests;     /* Number of requests left in the batch */
	unsigned long last_waited; /* Time last woken after wait for request */

	struct radix_tree_root	icq_tree;
	struct io_cq __rcu	*icq_hint;
	struct hlist_head	icq_list;

	struct work_struct release_work;
};

static inline struct io_context *ioc_task_link(struct io_context *ioc)
{
	/*
	 * if ref count is zero, don't allow sharing (ioc is going away, it's
	 * a race).
	 */
	if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
		atomic_inc(&ioc->nr_tasks);
		return ioc;
	}

	return NULL;
}

struct task_struct;
#ifdef CONFIG_BLOCK
void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
void exit_io_context(struct task_struct *task);
struct io_context *get_task_io_context(struct task_struct *task,
				       gfp_t gfp_flags, int node);
void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
void ioc_cgroup_changed(struct io_context *ioc);
#else
struct io_context;
static inline void put_io_context(struct io_context *ioc,
				  struct request_queue *locked_q) { }
static inline void exit_io_context(struct task_struct *task) { }
#endif

#endif
Commit	Line	Data
fd0928df JA	1	#ifndef IOCONTEXT_H
	2	#define IOCONTEXT_H
	3
4ac845a2	4	#include <linux/radix-tree.h>
34e6bbf2	5	#include <linux/rcupdate.h>
b2efa052	6	#include <linux/workqueue.h>
4ac845a2	7
dc86900e	8	enum {
c5869807 TH	9	ICQ_IOPRIO_CHANGED,
c5869807 TH	10	ICQ_CGROUP_CHANGED,
dc86900e TH	11	};
dc86900e TH	12
c5869807 TH	13	struct io_cq {
	14	struct request_queue *q;
	15	struct io_context *ioc;
fd0928df	16
7e5a8794 TH	17	/*
	18	* q_node and ioc_node link io_cq through icq_list of q and ioc
	19	* respectively. Both fields are unused once ioc_exit_icq() is
	20	* called and shared with __rcu_icq_cache and __rcu_head which are
	21	* used for RCU free of io_cq.
	22	*/
	23	union {
	24	struct list_head q_node;
	25	struct kmem_cache *__rcu_icq_cache;
	26	};
	27	union {
	28	struct hlist_node ioc_node;
	29	struct rcu_head __rcu_head;
	30	};
dc86900e	31
c5869807	32	unsigned long changed;
fd0928df JA	33	};
	34
	35	/*
d38ecf93 JA	36	* I/O subsystem state of the associated processes. It is refcounted
d38ecf93 JA	37	* and kmalloc'ed. These could be shared between processes.
fd0928df JA	38	*/
fd0928df JA	39	struct io_context {
d9c7d394	40	atomic_long_t refcount;
d38ecf93 JA	41	atomic_t nr_tasks;
	42
	43	/* all the fields below are protected by this lock */
	44	spinlock_t lock;
fd0928df JA	45
fd0928df JA	46	unsigned short ioprio;
31e4c28d	47
fd0928df JA	48	/*
	49	* For request batching
	50	*/
fd0928df	51	int nr_batch_requests; /* Number of requests left in the batch */
58c24a61	52	unsigned long last_waited; /* Time last woken after wait for request */
fd0928df	53
c5869807 TH	54	struct radix_tree_root icq_tree;
	55	struct io_cq __rcu *icq_hint;
	56	struct hlist_head icq_list;
b2efa052 TH	57
b2efa052 TH	58	struct work_struct release_work;
fd0928df JA	59	};
fd0928df JA	60
d38ecf93 JA	61	static inline struct io_context ioc_task_link(struct io_context ioc)
	62	{
	63	/*
	64	* if ref count is zero, don't allow sharing (ioc is going away, it's
	65	* a race).
	66	*/
d9c7d394	67	if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
cbb4f264	68	atomic_inc(&ioc->nr_tasks);
d38ecf93	69	return ioc;
d237e5c7	70	}
d38ecf93 JA	71
	72	return NULL;
	73	}
	74
b69f2292	75	struct task_struct;
da9cbc87	76	#ifdef CONFIG_BLOCK
b2efa052	77	void put_io_context(struct io_context ioc, struct request_queue locked_q);
b69f2292	78	void exit_io_context(struct task_struct *task);
6e736be7 TH	79	struct io_context get_task_io_context(struct task_struct task,
6e736be7 TH	80	gfp_t gfp_flags, int node);
dc86900e TH	81	void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
dc86900e TH	82	void ioc_cgroup_changed(struct io_context *ioc);
da9cbc87	83	#else
da9cbc87	84	struct io_context;
b2efa052 TH	85	static inline void put_io_context(struct io_context *ioc,
b2efa052 TH	86	struct request_queue *locked_q) { }
42ec57a8	87	static inline void exit_io_context(struct task_struct *task) { }
da9cbc87 JA	88	#endif
da9cbc87 JA	89
fd0928df	90	#endif