1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
19#ifndef _SYS_AIO_H_
20#define _SYS_AIO_H_
21
22#include <sys/types.h>
23#include <sys/signal.h>
24#ifdef _KERNEL
25#include <sys/queue.h>
26#include <sys/event.h>
27#include <sys/signalvar.h>
28#include <sys/uio.h>
29#endif
30
31/*
32 * Returned by aio_cancel:
33 */
34#define AIO_CANCELED 0x1
35#define AIO_NOTCANCELED 0x2
36#define AIO_ALLDONE 0x3
37
38/*
39 * LIO opcodes
40 */
41#define LIO_NOP 0x0
42#define LIO_WRITE 0x1
43#define LIO_READ 0x2
44#if __BSD_VISIBLE
45#define LIO_VECTORED 0x4
46#define LIO_WRITEV (LIO_WRITE | LIO_VECTORED)
47#define LIO_READV (LIO_READ | LIO_VECTORED)
48#endif
49#if defined(_KERNEL) || defined(_WANT_ALL_LIO_OPCODES)
50#define LIO_SYNC 0x8
51#define LIO_DSYNC (0x10 | LIO_SYNC)
52#define LIO_MLOCK 0x20
53#endif
54#if __BSD_VISIBLE
55#define LIO_FOFFSET 0x40
56#endif
57
58/* aio_read2/aio_write2 flags */
59#if __BSD_VISIBLE
60#define AIO_OP2_FOFFSET 0x00000001
61#define AIO_OP2_VECTORED 0x00000002
62#endif
63
64/*
65 * LIO modes
66 */
67#define LIO_NOWAIT 0x0
68#define LIO_WAIT 0x1
69
70/*
71 * Maximum number of operations in a single lio_listio call
72 */
73#define AIO_LISTIO_MAX 16
74
75#ifdef _KERNEL
76
77/* Default values of tunables for the AIO worker pool. */
78
79#ifndef MAX_AIO_PROCS
80#define MAX_AIO_PROCS 32
81#endif
82
83#ifndef TARGET_AIO_PROCS
84#define TARGET_AIO_PROCS 4
85#endif
86
87#ifndef AIOD_LIFETIME_DEFAULT
88#define AIOD_LIFETIME_DEFAULT (30 * hz)
89#endif
90
91#endif
92
93/*
94 * Private members for aiocb -- don't access
95 * directly.
96 */
97struct __aiocb_private {
98 long status;
99 long error;
100 void *spare;
101};
102
103/*
104 * I/O control block
105 */
106typedef struct aiocb {
107 int aio_fildes; /* File descriptor */
108 off_t aio_offset; /* File offset for I/O */
109 volatile void *aio_buf; /* I/O buffer in process space */
110 size_t aio_nbytes; /* Number of bytes for I/O */
111 int __spare__[2];
112 void *__spare2__;
113 int aio_lio_opcode; /* LIO opcode */
114 int aio_reqprio; /* Request priority -- ignored */
115 struct __aiocb_private _aiocb_private;
116 struct sigevent aio_sigevent; /* Signal to deliver */
117} aiocb_t;
118
119#define aio_iov aio_buf /* I/O scatter/gather list */
120#define aio_iovcnt aio_nbytes /* Length of aio_iov */
121
122#ifdef _KERNEL
123
124typedef void aio_cancel_fn_t(struct kaiocb *);
125typedef void aio_handle_fn_t(struct kaiocb *);
126
127/*
128 * Kernel version of an I/O control block.
129 *
130 * Locking key:
131 * * - need not protected
132 * a - locked by kaioinfo lock
133 * b - locked by backend lock
134 * c - locked by aio_job_mtx
135 */
136struct kaiocb {
137 TAILQ_ENTRY(kaiocb) list; /* (b) backend-specific list of jobs */
138 TAILQ_ENTRY(kaiocb) plist; /* (a) lists of pending / done jobs */
139 TAILQ_ENTRY(kaiocb) allist; /* (a) list of all jobs in proc */
140 int jobflags; /* (a) job flags */
141 int ioflags; /* (*) io flags */
142 int inblock; /* (*) input blocks */
143 int outblock; /* (*) output blocks */
144 int msgsnd; /* (*) messages sent */
145 int msgrcv; /* (*) messages received */
146 struct proc *userproc; /* (*) user process */
147 struct ucred *cred; /* (*) active credential when created */
148 struct file *fd_file; /* (*) pointer to file structure */
149 struct aioliojob *lio; /* (*) optional lio job */
150 struct aiocb *ujob; /* (*) pointer in userspace of aiocb */
151 struct knlist klist; /* (a) list of knotes */
152 struct aiocb uaiocb; /* (*) copy of user I/O control block */
153 struct uio uio; /* (*) storage for non-vectored uio */
154 struct iovec iov[1]; /* (*) storage for non-vectored uio */
155 struct uio *uiop; /* (*) Possibly malloced uio */
156 ksiginfo_t ksi; /* (a) realtime signal info */
157 uint64_t seqno; /* (*) job number */
158 aio_cancel_fn_t *cancel_fn; /* (a) backend cancel function */
159 aio_handle_fn_t *handle_fn; /* (c) backend handle function */
160 union { /* Backend-specific data fields */
161 struct { /* BIO backend */
162 volatile u_int nbio; /* Number of remaining bios */
163 int error; /* Worst error of all bios */
164 long nbytes; /* Bytes completed so far */
165 };
166 struct { /* fsync() requests */
167 int pending; /* (a) number of pending I/O */
168 };
169 struct { /* socket backend */
170 void *backend1;
171 long backend3;
172 int backend4;
173 };
174 };
175};
176
177struct socket;
178struct sockbuf;
179
180/*
181 * AIO backends should permit cancellation of queued requests waiting to
182 * be serviced by installing a cancel routine while the request is
183 * queued. The cancellation routine should dequeue the request if
184 * necessary and cancel it. Care must be used to handle races between
185 * queueing and dequeueing requests and cancellation.
186 *
187 * When queueing a request somewhere such that it can be cancelled, the
188 * caller should:
189 *
190 * 1) Acquire lock that protects the associated queue.
191 * 2) Call aio_set_cancel_function() to install the cancel routine.
192 * 3) If that fails, the request has a pending cancel and should be
193 * cancelled via aio_cancel().
194 * 4) Queue the request.
195 *
196 * When dequeueing a request to service it or hand it off to somewhere else,
197 * the caller should:
198 *
199 * 1) Acquire the lock that protects the associated queue.
200 * 2) Dequeue the request.
201 * 3) Call aio_clear_cancel_function() to clear the cancel routine.
202 * 4) If that fails, the cancel routine is about to be called. The
203 * caller should ignore the request.
204 *
205 * The cancel routine should:
206 *
207 * 1) Acquire the lock that protects the associated queue.
208 * 2) Call aio_cancel_cleared() to determine if the request is already
209 * dequeued due to a race with dequeueing thread.
210 * 3) If that fails, dequeue the request.
211 * 4) Cancel the request via aio_cancel().
212 */
213
214bool aio_cancel_cleared(struct kaiocb *job);
215void aio_cancel(struct kaiocb *job);
216bool aio_clear_cancel_function(struct kaiocb *job);
217void aio_complete(struct kaiocb *job, long status, int error);
218void aio_schedule(struct kaiocb *job, aio_handle_fn_t *func);
219bool aio_set_cancel_function(struct kaiocb *job, aio_cancel_fn_t *func);
220void aio_switch_vmspace(struct kaiocb *job);
221
222#else /* !_KERNEL */
223
224struct timespec;
225
226__BEGIN_DECLS
227/*
228 * Asynchronously read from a file
229 */
230int aio_read(struct aiocb *);
231#if __BSD_VISIBLE
232int aio_readv(struct aiocb *);
233#endif
234
235/*
236 * Asynchronously write to file
237 */
238int aio_write(struct aiocb *);
239#if __BSD_VISIBLE
240int aio_writev(struct aiocb *);
241#endif
242
243/*
244 * List I/O Asynchronously/synchronously read/write to/from file
245 * "lio_mode" specifies whether or not the I/O is synchronous.
246 * "acb_list" is an array of "nacb_listent" I/O control blocks.
247 * when all I/Os are complete, the optional signal "sig" is sent.
248 */
249int lio_listio(int, struct aiocb *__restrict const *__restrict, int,
250 struct sigevent *);
251
252/*
253 * Get completion status
254 * returns EINPROGRESS until I/O is complete.
255 * this routine does not block.
256 */
257int aio_error(const struct aiocb *);
258
259/*
260 * Finish up I/O, releasing I/O resources and returns the value
261 * that would have been associated with a synchronous I/O request.
262 * This routine must be called once and only once for each
263 * I/O control block who has had I/O associated with it.
264 */
265ssize_t aio_return(struct aiocb *);
266
267/*
268 * Cancel I/O
269 */
270int aio_cancel(int, struct aiocb *);
271
272/*
273 * Suspend until all specified I/O or timeout is complete.
274 */
275int aio_suspend(const struct aiocb * const[], int, const struct timespec *);
276
277/*
278 * Asynchronous mlock
279 */
280int aio_mlock(struct aiocb *);
281
282#if __BSD_VISIBLE
283ssize_t aio_waitcomplete(struct aiocb **, struct timespec *);
284int aio_read2(struct aiocb *, int);
285int aio_write2(struct aiocb *, int);
286#endif
287
288int aio_fsync(int op, struct aiocb *aiocbp);
289__END_DECLS
290
291#endif /* !_KERNEL */
292
293#endif /* !_SYS_AIO_H_ */