1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1997 John S. Dyson.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. John S. Dyson's name may not be used to endorse or promote products
12 *    derived from this software without specific prior written permission.
13 *
14 * DISCLAIMER:  This code isn't warranted to do anything useful.  Anything
15 * bad that happens because of using this software isn't the responsibility
16 * of the author.  This software is distributed AS-IS.
17 *
18 * $FreeBSD$
19 */
20
21#ifndef _SYS_AIO_H_
22#define	_SYS_AIO_H_
23
24#include <sys/types.h>
25#include <sys/signal.h>
26#ifdef _KERNEL
27#include <sys/queue.h>
28#include <sys/event.h>
29#include <sys/signalvar.h>
30#endif
31
32/*
33 * Returned by aio_cancel:
34 */
35#define	AIO_CANCELED		0x1
36#define	AIO_NOTCANCELED		0x2
37#define	AIO_ALLDONE		0x3
38
39/*
40 * LIO opcodes
41 */
42#define	LIO_NOP			0x0
43#define LIO_WRITE		0x1
44#define	LIO_READ		0x2
45#ifdef _KERNEL
46#define	LIO_SYNC		0x3
47#define	LIO_MLOCK		0x4
48#endif
49
50/*
51 * LIO modes
52 */
53#define	LIO_NOWAIT		0x0
54#define	LIO_WAIT		0x1
55
56/*
57 * Maximum number of operations in a single lio_listio call
58 */
59#define	AIO_LISTIO_MAX		16
60
61#ifdef _KERNEL
62
63/* Default values of tunables for the AIO worker pool. */
64
65#ifndef MAX_AIO_PROCS
66#define MAX_AIO_PROCS		32
67#endif
68
69#ifndef TARGET_AIO_PROCS
70#define TARGET_AIO_PROCS	4
71#endif
72
73#ifndef AIOD_LIFETIME_DEFAULT
74#define AIOD_LIFETIME_DEFAULT	(30 * hz)
75#endif
76
77#endif
78
79/*
80 * Private members for aiocb -- don't access
81 * directly.
82 */
83struct __aiocb_private {
84	long	status;
85	long	error;
86	void	*kernelinfo;
87};
88
89/*
90 * I/O control block
91 */
92typedef struct aiocb {
93	int	aio_fildes;		/* File descriptor */
94	off_t	aio_offset;		/* File offset for I/O */
95	volatile void *aio_buf;         /* I/O buffer in process space */
96	size_t	aio_nbytes;		/* Number of bytes for I/O */
97	int	__spare__[2];
98	void	*__spare2__;
99	int	aio_lio_opcode;		/* LIO opcode */
100	int	aio_reqprio;		/* Request priority -- ignored */
101	struct	__aiocb_private	_aiocb_private;
102	struct	sigevent aio_sigevent;	/* Signal to deliver */
103} aiocb_t;
104
105#ifdef _KERNEL
106
107typedef void aio_cancel_fn_t(struct kaiocb *);
108typedef void aio_handle_fn_t(struct kaiocb *);
109
110/*
111 * Kernel version of an I/O control block.
112 *
113 * Locking key:
114 * * - need not protected
115 * a - locked by kaioinfo lock
116 * b - locked by backend lock
117 * c - locked by aio_job_mtx
118 */
119struct kaiocb {
120	TAILQ_ENTRY(kaiocb) list;	/* (b) backend-specific list of jobs */
121	TAILQ_ENTRY(kaiocb) plist;	/* (a) lists of pending / done jobs */
122	TAILQ_ENTRY(kaiocb) allist;	/* (a) list of all jobs in proc */
123	int	jobflags;		/* (a) job flags */
124	int	inblock;		/* (*) input blocks */
125	int	outblock;		/* (*) output blocks */
126	int	msgsnd;			/* (*) messages sent */
127	int	msgrcv;			/* (*) messages received */
128	struct	proc *userproc;		/* (*) user process */
129	struct	ucred *cred;		/* (*) active credential when created */
130	struct	file *fd_file;		/* (*) pointer to file structure */
131	struct	aioliojob *lio;		/* (*) optional lio job */
132	struct	aiocb *ujob;		/* (*) pointer in userspace of aiocb */
133	struct	knlist klist;		/* (a) list of knotes */
134	struct	aiocb uaiocb;		/* (*) copy of user I/O control block */
135	ksiginfo_t ksi;			/* (a) realtime signal info */
136	uint64_t seqno;			/* (*) job number */
137	aio_cancel_fn_t *cancel_fn;	/* (a) backend cancel function */
138	aio_handle_fn_t *handle_fn;	/* (c) backend handle function */
139	union {				/* Backend-specific data fields */
140		struct {		/* BIO backend */
141			struct bio *bp;	/* (*) BIO pointer */
142			struct buf *pbuf; /* (*) buffer pointer */
143			struct vm_page *pages[btoc(MAXPHYS)+1]; /* (*) */
144			int	npages;	/* (*) number of pages */
145		};
146		struct {		/* fsync() requests */
147			int	pending; /* (a) number of pending I/O */
148		};
149		struct {
150			void	*backend1;
151			void	*backend2;
152			long	backend3;
153			int	backend4;
154		};
155	};
156};
157
158struct socket;
159struct sockbuf;
160
161/*
162 * AIO backends should permit cancellation of queued requests waiting to
163 * be serviced by installing a cancel routine while the request is
164 * queued.  The cancellation routine should dequeue the request if
165 * necessary and cancel it.  Care must be used to handle races between
166 * queueing and dequeueing requests and cancellation.
167 *
168 * When queueing a request somewhere such that it can be cancelled, the
169 * caller should:
170 *
171 *  1) Acquire lock that protects the associated queue.
172 *  2) Call aio_set_cancel_function() to install the cancel routine.
173 *  3) If that fails, the request has a pending cancel and should be
174 *     cancelled via aio_cancel().
175 *  4) Queue the request.
176 *
177 * When dequeueing a request to service it or hand it off to somewhere else,
178 * the caller should:
179 *
180 *  1) Acquire the lock that protects the associated queue.
181 *  2) Dequeue the request.
182 *  3) Call aio_clear_cancel_function() to clear the cancel routine.
183 *  4) If that fails, the cancel routine is about to be called.  The
184 *     caller should ignore the request.
185 *
186 * The cancel routine should:
187 *
188 *  1) Acquire the lock that protects the associated queue.
189 *  2) Call aio_cancel_cleared() to determine if the request is already
190 *     dequeued due to a race with dequeueing thread.
191 *  3) If that fails, dequeue the request.
192 *  4) Cancel the request via aio_cancel().
193 */
194
195bool	aio_cancel_cleared(struct kaiocb *job);
196void	aio_cancel(struct kaiocb *job);
197bool	aio_clear_cancel_function(struct kaiocb *job);
198void	aio_complete(struct kaiocb *job, long status, int error);
199void	aio_schedule(struct kaiocb *job, aio_handle_fn_t *func);
200bool	aio_set_cancel_function(struct kaiocb *job, aio_cancel_fn_t *func);
201void	aio_switch_vmspace(struct kaiocb *job);
202
203#else /* !_KERNEL */
204
205struct timespec;
206
207__BEGIN_DECLS
208/*
209 * Asynchronously read from a file
210 */
211int	aio_read(struct aiocb *);
212
213/*
214 * Asynchronously write to file
215 */
216int	aio_write(struct aiocb *);
217
218/*
219 * List I/O Asynchronously/synchronously read/write to/from file
220 *	"lio_mode" specifies whether or not the I/O is synchronous.
221 *	"acb_list" is an array of "nacb_listent" I/O control blocks.
222 *	when all I/Os are complete, the optional signal "sig" is sent.
223 */
224int	lio_listio(int, struct aiocb *__restrict const *__restrict, int,
225    struct sigevent *);
226
227/*
228 * Get completion status
229 *	returns EINPROGRESS until I/O is complete.
230 *	this routine does not block.
231 */
232int	aio_error(const struct aiocb *);
233
234/*
235 * Finish up I/O, releasing I/O resources and returns the value
236 *	that would have been associated with a synchronous I/O request.
237 *	This routine must be called once and only once for each
238 *	I/O control block who has had I/O associated with it.
239 */
240ssize_t	aio_return(struct aiocb *);
241
242/*
243 * Cancel I/O
244 */
245int	aio_cancel(int, struct aiocb *);
246
247/*
248 * Suspend until all specified I/O or timeout is complete.
249 */
250int	aio_suspend(const struct aiocb * const[], int, const struct timespec *);
251
252/*
253 * Asynchronous mlock
254 */
255int	aio_mlock(struct aiocb *);
256
257#if __BSD_VISIBLE
258ssize_t	aio_waitcomplete(struct aiocb **, struct timespec *);
259#endif
260
261int	aio_fsync(int op, struct aiocb *aiocbp);
262__END_DECLS
263
264#endif /* !_KERNEL */
265
266#endif /* !_SYS_AIO_H_ */
267