aio.h 8.0 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6
#ifndef __LINUX__AIO_H
#define __LINUX__AIO_H

#include <linux/list.h>
#include <linux/workqueue.h>
#include <linux/aio_abi.h>
7
#include <linux/uio.h>
L
Linus Torvalds 已提交
8 9

#include <asm/atomic.h>
B
Badari Pulavarty 已提交
10
#include <linux/uio.h>
L
Linus Torvalds 已提交
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

#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 */
Z
Zach Brown 已提交
29 30 31 32 33 34
/*
 * 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 */
L
Linus Torvalds 已提交
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
#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)

53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
/* 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.
 */
L
Linus Torvalds 已提交
87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102
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 *);

	union {
		void __user		*user;
		struct task_struct	*tsk;
	} ki_obj;
103

L
Linus Torvalds 已提交
104
	__u64			ki_user_data;	/* user's data for completion */
105
	wait_queue_t		ki_wait;
L
Linus Torvalds 已提交
106
	loff_t			ki_pos;
107 108

	void			*private;
L
Linus Torvalds 已提交
109 110 111 112 113 114
	/* 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 */
	long			ki_retried; 	/* just for testing */
115
	struct iovec		ki_inline_vec;	/* inline vector */
B
Badari Pulavarty 已提交
116 117 118
 	struct iovec		*ki_iovec;
 	unsigned long		ki_nr_segs;
 	unsigned long		ki_cur_seg;
L
Linus Torvalds 已提交
119

120 121
	struct list_head	ki_list;	/* the aio core uses this
						 * for cancellation */
L
Linus Torvalds 已提交
122 123 124 125 126 127 128 129 130 131
};

#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);			\
132
		(x)->ki_ctx = NULL;			\
L
Linus Torvalds 已提交
133
		(x)->ki_cancel = NULL;			\
134
		(x)->ki_retry = NULL;			\
L
Linus Torvalds 已提交
135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
		(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 */

192
	/* sys_io_setup currently limits this to an unsigned int */
L
Linus Torvalds 已提交
193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218
	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));

219
#define get_ioctx(kioctx) do {						\
220
	BUG_ON(atomic_read(&(kioctx)->users) <= 0);			\
221 222 223
	atomic_inc(&(kioctx)->users);					\
} while (0)
#define put_ioctx(kioctx) do {						\
224
	BUG_ON(atomic_read(&(kioctx)->users) <= 0);			\
225 226 227
	if (unlikely(atomic_dec_and_test(&(kioctx)->users))) 		\
		__put_ioctx(kioctx);					\
} while (0)
L
Linus Torvalds 已提交
228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250

#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: */
251 252
extern unsigned long aio_nr;
extern unsigned long aio_max_nr;
L
Linus Torvalds 已提交
253 254

#endif /* __LINUX__AIO_H */