[linux-block.git] / include / linux / aio.h

#ifndef __LINUX__AIO_H
#define __LINUX__AIO_H

#include <linux/list.h>
#include <linux/workqueue.h>
#include <linux/aio_abi.h>

#include <asm/atomic.h>

#define AIO_MAXSEGS		4
#define AIO_KIOGRP_NR_ATOMIC	8

struct kioctx;

/* Notes on cancelling a kiocb:
 *	If a kiocb is cancelled, aio_complete may return 0 to indicate 
 *	that cancel has not yet disposed of the kiocb.  All cancel 
 *	operations *must* call aio_put_req to dispose of the kiocb 
 *	to guard against races with the completion code.
 */
#define KIOCB_C_CANCELLED	0x01
#define KIOCB_C_COMPLETE	0x02

#define KIOCB_SYNC_KEY		(~0U)

/* ki_flags bits */
/*
 * This may be used for cancel/retry serialization in the future, but
 * for now it's unused and we probably don't want modules to even
 * think they can use it.
 */
/* #define KIF_LOCKED		0 */
#define KIF_KICKED		1
#define KIF_CANCELLED		2

#define kiocbTryLock(iocb)	test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
#define kiocbTryKick(iocb)	test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)

#define kiocbSetLocked(iocb)	set_bit(KIF_LOCKED, &(iocb)->ki_flags)
#define kiocbSetKicked(iocb)	set_bit(KIF_KICKED, &(iocb)->ki_flags)
#define kiocbSetCancelled(iocb)	set_bit(KIF_CANCELLED, &(iocb)->ki_flags)

#define kiocbClearLocked(iocb)	clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
#define kiocbClearKicked(iocb)	clear_bit(KIF_KICKED, &(iocb)->ki_flags)
#define kiocbClearCancelled(iocb)	clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)

#define kiocbIsLocked(iocb)	test_bit(KIF_LOCKED, &(iocb)->ki_flags)
#define kiocbIsKicked(iocb)	test_bit(KIF_KICKED, &(iocb)->ki_flags)
#define kiocbIsCancelled(iocb)	test_bit(KIF_CANCELLED, &(iocb)->ki_flags)

/* is there a better place to document function pointer methods? */
/**
 * ki_retry	-	iocb forward progress callback
 * @kiocb:	The kiocb struct to advance by performing an operation.
 *
 * This callback is called when the AIO core wants a given AIO operation
 * to make forward progress.  The kiocb argument describes the operation
 * that is to be performed.  As the operation proceeds, perhaps partially,
 * ki_retry is expected to update the kiocb with progress made.  Typically
 * ki_retry is set in the AIO core and it itself calls file_operations
 * helpers.
 *
 * ki_retry's return value determines when the AIO operation is completed
 * and an event is generated in the AIO event ring.  Except the special
 * return values described below, the value that is returned from ki_retry
 * is transferred directly into the completion ring as the operation's
 * resulting status.  Once this has happened ki_retry *MUST NOT* reference
 * the kiocb pointer again.
 *
 * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
 * will be called on the kiocb pointer in the future.  The AIO core will
 * not ask the method again -- ki_retry must ensure forward progress.
 * aio_complete() must be called once and only once in the future, multiple
 * calls may result in undefined behaviour.
 *
 * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
 * will be called on the kiocb pointer in the future.  This may happen
 * through generic helpers that associate kiocb->ki_wait with a wait
 * queue head that ki_retry uses via current->io_wait.  It can also happen
 * with custom tracking and manual calls to kick_iocb(), though that is
 * discouraged.  In either case, kick_iocb() must be called once and only
 * once.  ki_retry must ensure forward progress, the AIO core will wait
 * indefinitely for kick_iocb() to be called.
 */
struct kiocb {
	struct list_head	ki_run_list;
	long			ki_flags;
	int			ki_users;
	unsigned		ki_key;		/* id of this request */

	struct file		*ki_filp;
	struct kioctx		*ki_ctx;	/* may be NULL for sync ops */
	int			(*ki_cancel)(struct kiocb *, struct io_event *);
	ssize_t			(*ki_retry)(struct kiocb *);
	void			(*ki_dtor)(struct kiocb *);

	struct list_head	ki_list;	/* the aio core uses this
						 * for cancellation */

	union {
		void __user		*user;
		struct task_struct	*tsk;
	} ki_obj;
	__u64			ki_user_data;	/* user's data for completion */
	loff_t			ki_pos;
	/* State that we remember to be able to restart/retry  */
	unsigned short		ki_opcode;
	size_t			ki_nbytes; 	/* copy of iocb->aio_nbytes */
	char 			__user *ki_buf;	/* remaining iocb->aio_buf */
	size_t			ki_left; 	/* remaining bytes */
	wait_queue_t		ki_wait;
	long			ki_retried; 	/* just for testing */
	long			ki_kicked; 	/* just for testing */
	long			ki_queued; 	/* just for testing */

	void			*private;
};

#define is_sync_kiocb(iocb)	((iocb)->ki_key == KIOCB_SYNC_KEY)
#define init_sync_kiocb(x, filp)			\
	do {						\
		struct task_struct *tsk = current;	\
		(x)->ki_flags = 0;			\
		(x)->ki_users = 1;			\
		(x)->ki_key = KIOCB_SYNC_KEY;		\
		(x)->ki_filp = (filp);			\
		(x)->ki_ctx = &tsk->active_mm->default_kioctx;	\
		(x)->ki_cancel = NULL;			\
		(x)->ki_dtor = NULL;			\
		(x)->ki_obj.tsk = tsk;			\
		(x)->ki_user_data = 0;                  \
		init_wait((&(x)->ki_wait));             \
	} while (0)

#define AIO_RING_MAGIC			0xa10a10a1
#define AIO_RING_COMPAT_FEATURES	1
#define AIO_RING_INCOMPAT_FEATURES	0
struct aio_ring {
	unsigned	id;	/* kernel internal index number */
	unsigned	nr;	/* number of io_events */
	unsigned	head;
	unsigned	tail;

	unsigned	magic;
	unsigned	compat_features;
	unsigned	incompat_features;
	unsigned	header_length;	/* size of aio_ring */


	struct io_event		io_events[0];
}; /* 128 bytes + ring size */

#define aio_ring_avail(info, ring)	(((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)

#define AIO_RING_PAGES	8
struct aio_ring_info {
	unsigned long		mmap_base;
	unsigned long		mmap_size;

	struct page		**ring_pages;
	spinlock_t		ring_lock;
	long			nr_pages;

	unsigned		nr, tail;

	struct page		*internal_pages[AIO_RING_PAGES];
};

struct kioctx {
	atomic_t		users;
	int			dead;
	struct mm_struct	*mm;

	/* This needs improving */
	unsigned long		user_id;
	struct kioctx		*next;

	wait_queue_head_t	wait;

	spinlock_t		ctx_lock;

	int			reqs_active;
	struct list_head	active_reqs;	/* used for cancellation */
	struct list_head	run_list;	/* used for kicked reqs */

	unsigned		max_reqs;

	struct aio_ring_info	ring_info;

	struct work_struct	wq;
};

/* prototypes */
extern unsigned aio_max_size;

extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
extern int FASTCALL(aio_put_req(struct kiocb *iocb));
extern void FASTCALL(kick_iocb(struct kiocb *iocb));
extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
struct mm_struct;
extern void FASTCALL(exit_aio(struct mm_struct *mm));
extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
extern int FASTCALL(io_submit_one(struct kioctx *ctx,
			struct iocb __user *user_iocb, struct iocb *iocb));

/* semi private, but used by the 32bit emulations: */
struct kioctx *lookup_ioctx(unsigned long ctx_id);
int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
				  struct iocb *iocb));

#define get_ioctx(kioctx)	do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
#define put_ioctx(kioctx)	do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0)

#define in_aio() !is_sync_wait(current->io_wait)
/* may be used for debugging */
#define warn_if_async()							\
do {									\
	if (in_aio()) {							\
		printk(KERN_ERR "%s(%s:%d) called in async context!\n",	\
			__FUNCTION__, __FILE__, __LINE__);		\
		dump_stack();						\
	}								\
} while (0)

#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
#define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)

#include <linux/aio_abi.h>

static inline struct kiocb *list_kiocb(struct list_head *h)
{
	return list_entry(h, struct kiocb, ki_list);
}

/* for sysctl: */
extern atomic_t aio_nr;
extern unsigned aio_max_nr;

#endif /* __LINUX__AIO_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __LINUX__AIO_H
	2	#define __LINUX__AIO_H
	3
	4	#include <linux/list.h>
	5	#include <linux/workqueue.h>
	6	#include <linux/aio_abi.h>
	7
	8	#include <asm/atomic.h>
	9
	10	#define AIO_MAXSEGS 4
	11	#define AIO_KIOGRP_NR_ATOMIC 8
	12
	13	struct kioctx;
	14
	15	/* Notes on cancelling a kiocb:
	16	* If a kiocb is cancelled, aio_complete may return 0 to indicate
	17	* that cancel has not yet disposed of the kiocb. All cancel
	18	* operations must call aio_put_req to dispose of the kiocb
	19	* to guard against races with the completion code.
	20	*/
	21	#define KIOCB_C_CANCELLED 0x01
	22	#define KIOCB_C_COMPLETE 0x02
	23
	24	#define KIOCB_SYNC_KEY (~0U)
	25
	26	/* ki_flags bits */
4faa5285 ZB	27	/*
	28	* This may be used for cancel/retry serialization in the future, but
	29	* for now it's unused and we probably don't want modules to even
	30	* think they can use it.
	31	*/
	32	/* #define KIF_LOCKED 0 */
1da177e4 LT	33	#define KIF_KICKED 1
	34	#define KIF_CANCELLED 2
	35
	36	#define kiocbTryLock(iocb) test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
	37	#define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
	38
	39	#define kiocbSetLocked(iocb) set_bit(KIF_LOCKED, &(iocb)->ki_flags)
	40	#define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags)
	41	#define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
	42
	43	#define kiocbClearLocked(iocb) clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
	44	#define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags)
	45	#define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
	46
	47	#define kiocbIsLocked(iocb) test_bit(KIF_LOCKED, &(iocb)->ki_flags)
	48	#define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags)
	49	#define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
	50
897f15fb ZB	51	/* is there a better place to document function pointer methods? */
	52	/**
	53	* ki_retry - iocb forward progress callback
	54	* @kiocb: The kiocb struct to advance by performing an operation.
	55	*
	56	* This callback is called when the AIO core wants a given AIO operation
	57	* to make forward progress. The kiocb argument describes the operation
	58	* that is to be performed. As the operation proceeds, perhaps partially,
	59	* ki_retry is expected to update the kiocb with progress made. Typically
	60	* ki_retry is set in the AIO core and it itself calls file_operations
	61	* helpers.
	62	*
	63	* ki_retry's return value determines when the AIO operation is completed
	64	* and an event is generated in the AIO event ring. Except the special
	65	* return values described below, the value that is returned from ki_retry
	66	* is transferred directly into the completion ring as the operation's
	67	* resulting status. Once this has happened ki_retry MUST NOT reference
	68	* the kiocb pointer again.
	69	*
	70	* If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
	71	* will be called on the kiocb pointer in the future. The AIO core will
	72	* not ask the method again -- ki_retry must ensure forward progress.
	73	* aio_complete() must be called once and only once in the future, multiple
	74	* calls may result in undefined behaviour.
	75	*
	76	* If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
	77	* will be called on the kiocb pointer in the future. This may happen
	78	* through generic helpers that associate kiocb->ki_wait with a wait
	79	* queue head that ki_retry uses via current->io_wait. It can also happen
	80	* with custom tracking and manual calls to kick_iocb(), though that is
	81	* discouraged. In either case, kick_iocb() must be called once and only
	82	* once. ki_retry must ensure forward progress, the AIO core will wait
	83	* indefinitely for kick_iocb() to be called.
	84	*/
1da177e4 LT	85	struct kiocb {
	86	struct list_head ki_run_list;
	87	long ki_flags;
	88	int ki_users;
	89	unsigned ki_key; /* id of this request */
	90
	91	struct file *ki_filp;
	92	struct kioctx ki_ctx; / may be NULL for sync ops */
	93	int (ki_cancel)(struct kiocb , struct io_event *);
	94	ssize_t (ki_retry)(struct kiocb );
	95	void (ki_dtor)(struct kiocb );
	96
	97	struct list_head ki_list; /* the aio core uses this
	98	* for cancellation */
	99
	100	union {
	101	void __user *user;
	102	struct task_struct *tsk;
	103	} ki_obj;
	104	__u64 ki_user_data; /* user's data for completion */
	105	loff_t ki_pos;
	106	/* State that we remember to be able to restart/retry */
	107	unsigned short ki_opcode;
	108	size_t ki_nbytes; /* copy of iocb->aio_nbytes */
	109	char __user ki_buf; / remaining iocb->aio_buf */
	110	size_t ki_left; /* remaining bytes */
	111	wait_queue_t ki_wait;
	112	long ki_retried; /* just for testing */
	113	long ki_kicked; /* just for testing */
	114	long ki_queued; /* just for testing */
	115
	116	void *private;
	117	};
	118
	119	#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
	120	#define init_sync_kiocb(x, filp) \
	121	do { \
	122	struct task_struct *tsk = current; \
	123	(x)->ki_flags = 0; \
	124	(x)->ki_users = 1; \
	125	(x)->ki_key = KIOCB_SYNC_KEY; \
	126	(x)->ki_filp = (filp); \
	127	(x)->ki_ctx = &tsk->active_mm->default_kioctx; \
	128	(x)->ki_cancel = NULL; \
	129	(x)->ki_dtor = NULL; \
	130	(x)->ki_obj.tsk = tsk; \
	131	(x)->ki_user_data = 0; \
	132	init_wait((&(x)->ki_wait)); \
	133	} while (0)
	134
	135	#define AIO_RING_MAGIC 0xa10a10a1
	136	#define AIO_RING_COMPAT_FEATURES 1
	137	#define AIO_RING_INCOMPAT_FEATURES 0
	138	struct aio_ring {
	139	unsigned id; /* kernel internal index number */
	140	unsigned nr; /* number of io_events */
	141	unsigned head;
	142	unsigned tail;
	143
	144	unsigned magic;
	145	unsigned compat_features;
	146	unsigned incompat_features;
	147	unsigned header_length; /* size of aio_ring */
	148
149
150	struct io_event io_events[0];
151	}; /* 128 bytes + ring size */
152
153	#define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
154
155	#define AIO_RING_PAGES 8
156	struct aio_ring_info {
157	unsigned long mmap_base;
158	unsigned long mmap_size;
159
160	struct page **ring_pages;
161	spinlock_t ring_lock;
162	long nr_pages;
163
164	unsigned nr, tail;
165
166	struct page *internal_pages[AIO_RING_PAGES];
167	};
168
169	struct kioctx {
170	atomic_t users;
171	int dead;
172	struct mm_struct *mm;
173
174	/* This needs improving */
175	unsigned long user_id;
176	struct kioctx *next;
177
178	wait_queue_head_t wait;
179
180	spinlock_t ctx_lock;
181
182	int reqs_active;
183	struct list_head active_reqs; /* used for cancellation */
184	struct list_head run_list; /* used for kicked reqs */
185
186	unsigned max_reqs;
187
188	struct aio_ring_info ring_info;
189
190	struct work_struct wq;
191	};
192
193	/* prototypes */
194	extern unsigned aio_max_size;
195
196	extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
197	extern int FASTCALL(aio_put_req(struct kiocb *iocb));
198	extern void FASTCALL(kick_iocb(struct kiocb *iocb));
199	extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
200	extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
201	struct mm_struct;
202	extern void FASTCALL(exit_aio(struct mm_struct *mm));
203	extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
204	extern int FASTCALL(io_submit_one(struct kioctx *ctx,
205	struct iocb __user user_iocb, struct iocb iocb));
206
207	/* semi private, but used by the 32bit emulations: */
208	struct kioctx *lookup_ioctx(unsigned long ctx_id);
209	int FASTCALL(io_submit_one(struct kioctx ctx, struct iocb __user user_iocb,
210	struct iocb *iocb));
211
212	#define get_ioctx(kioctx) do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
213	#define put_ioctx(kioctx) do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0)
214
215	#define in_aio() !is_sync_wait(current->io_wait)
216	/* may be used for debugging */
217	#define warn_if_async() \
218	do { \
219	if (in_aio()) { \
220	printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
221	__FUNCTION__, __FILE__, __LINE__); \
222	dump_stack(); \
223	} \
224	} while (0)
225
226	#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
227	#define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
228
229	#include <linux/aio_abi.h>
230
231	static inline struct kiocb list_kiocb(struct list_head h)
232	{
233	return list_entry(h, struct kiocb, ki_list);
234	}
235
236	/* for sysctl: */
237	extern atomic_t aio_nr;
238	extern unsigned aio_max_nr;
239
240	#endif /* __LINUX__AIO_H */