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