2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1997 John S. Dyson. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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.
24 #include <sys/types.h>
25 #include <sys/signal.h>
27 #include <sys/queue.h>
28 #include <sys/event.h>
29 #include <sys/signalvar.h>
34 * Returned by aio_cancel:
36 #define AIO_CANCELED 0x1
37 #define AIO_NOTCANCELED 0x2
38 #define AIO_ALLDONE 0x3
46 #if defined(_KERNEL) || defined(_WANT_ALL_LIO_OPCODES)
49 #define LIO_WRITEV 0x5
57 #define LIO_NOWAIT 0x0
61 * Maximum number of operations in a single lio_listio call
63 #define AIO_LISTIO_MAX 16
67 /* Default values of tunables for the AIO worker pool. */
70 #define MAX_AIO_PROCS 32
73 #ifndef TARGET_AIO_PROCS
74 #define TARGET_AIO_PROCS 4
77 #ifndef AIOD_LIFETIME_DEFAULT
78 #define AIOD_LIFETIME_DEFAULT (30 * hz)
84 * Private members for aiocb -- don't access
87 struct __aiocb_private {
96 typedef struct aiocb {
97 int aio_fildes; /* File descriptor */
98 off_t aio_offset; /* File offset for I/O */
99 volatile void *aio_buf; /* I/O buffer in process space */
100 size_t aio_nbytes; /* Number of bytes for I/O */
103 int aio_lio_opcode; /* LIO opcode */
104 int aio_reqprio; /* Request priority -- ignored */
105 struct __aiocb_private _aiocb_private;
106 struct sigevent aio_sigevent; /* Signal to deliver */
109 #define aio_iov aio_buf /* I/O scatter/gather list */
110 #define aio_iovcnt aio_nbytes /* Length of aio_iov */
114 typedef void aio_cancel_fn_t(struct kaiocb *);
115 typedef void aio_handle_fn_t(struct kaiocb *);
118 * Kernel version of an I/O control block.
121 * * - need not protected
122 * a - locked by kaioinfo lock
123 * b - locked by backend lock
124 * c - locked by aio_job_mtx
127 TAILQ_ENTRY(kaiocb) list; /* (b) backend-specific list of jobs */
128 TAILQ_ENTRY(kaiocb) plist; /* (a) lists of pending / done jobs */
129 TAILQ_ENTRY(kaiocb) allist; /* (a) list of all jobs in proc */
130 int jobflags; /* (a) job flags */
131 int inblock; /* (*) input blocks */
132 int outblock; /* (*) output blocks */
133 int msgsnd; /* (*) messages sent */
134 int msgrcv; /* (*) messages received */
135 struct proc *userproc; /* (*) user process */
136 struct ucred *cred; /* (*) active credential when created */
137 struct file *fd_file; /* (*) pointer to file structure */
138 struct aioliojob *lio; /* (*) optional lio job */
139 struct aiocb *ujob; /* (*) pointer in userspace of aiocb */
140 struct knlist klist; /* (a) list of knotes */
141 struct aiocb uaiocb; /* (*) copy of user I/O control block */
142 struct uio uio; /* (*) storage for non-vectored uio */
143 struct iovec iov[1]; /* (*) storage for non-vectored uio */
144 struct uio *uiop; /* (*) Possibly malloced uio */
145 ksiginfo_t ksi; /* (a) realtime signal info */
146 uint64_t seqno; /* (*) job number */
147 aio_cancel_fn_t *cancel_fn; /* (a) backend cancel function */
148 aio_handle_fn_t *handle_fn; /* (c) backend handle function */
149 union { /* Backend-specific data fields */
150 struct { /* BIO backend */
151 int nbio; /* Number of remaining bios */
152 int error; /* Worst error of all bios */
153 long nbytes; /* Bytes completed so far */
155 struct { /* fsync() requests */
156 int pending; /* (a) number of pending I/O */
158 struct { /* socket backend */
170 * AIO backends should permit cancellation of queued requests waiting to
171 * be serviced by installing a cancel routine while the request is
172 * queued. The cancellation routine should dequeue the request if
173 * necessary and cancel it. Care must be used to handle races between
174 * queueing and dequeueing requests and cancellation.
176 * When queueing a request somewhere such that it can be cancelled, the
179 * 1) Acquire lock that protects the associated queue.
180 * 2) Call aio_set_cancel_function() to install the cancel routine.
181 * 3) If that fails, the request has a pending cancel and should be
182 * cancelled via aio_cancel().
183 * 4) Queue the request.
185 * When dequeueing a request to service it or hand it off to somewhere else,
188 * 1) Acquire the lock that protects the associated queue.
189 * 2) Dequeue the request.
190 * 3) Call aio_clear_cancel_function() to clear the cancel routine.
191 * 4) If that fails, the cancel routine is about to be called. The
192 * caller should ignore the request.
194 * The cancel routine should:
196 * 1) Acquire the lock that protects the associated queue.
197 * 2) Call aio_cancel_cleared() to determine if the request is already
198 * dequeued due to a race with dequeueing thread.
199 * 3) If that fails, dequeue the request.
200 * 4) Cancel the request via aio_cancel().
203 bool aio_cancel_cleared(struct kaiocb *job);
204 void aio_cancel(struct kaiocb *job);
205 bool aio_clear_cancel_function(struct kaiocb *job);
206 void aio_complete(struct kaiocb *job, long status, int error);
207 void aio_schedule(struct kaiocb *job, aio_handle_fn_t *func);
208 bool aio_set_cancel_function(struct kaiocb *job, aio_cancel_fn_t *func);
209 void aio_switch_vmspace(struct kaiocb *job);
217 * Asynchronously read from a file
219 int aio_read(struct aiocb *);
221 int aio_readv(struct aiocb *);
225 * Asynchronously write to file
227 int aio_write(struct aiocb *);
229 int aio_writev(struct aiocb *);
233 * List I/O Asynchronously/synchronously read/write to/from file
234 * "lio_mode" specifies whether or not the I/O is synchronous.
235 * "acb_list" is an array of "nacb_listent" I/O control blocks.
236 * when all I/Os are complete, the optional signal "sig" is sent.
238 int lio_listio(int, struct aiocb *__restrict const *__restrict, int,
242 * Get completion status
243 * returns EINPROGRESS until I/O is complete.
244 * this routine does not block.
246 int aio_error(const struct aiocb *);
249 * Finish up I/O, releasing I/O resources and returns the value
250 * that would have been associated with a synchronous I/O request.
251 * This routine must be called once and only once for each
252 * I/O control block who has had I/O associated with it.
254 ssize_t aio_return(struct aiocb *);
259 int aio_cancel(int, struct aiocb *);
262 * Suspend until all specified I/O or timeout is complete.
264 int aio_suspend(const struct aiocb * const[], int, const struct timespec *);
269 int aio_mlock(struct aiocb *);
272 ssize_t aio_waitcomplete(struct aiocb **, struct timespec *);
275 int aio_fsync(int op, struct aiocb *aiocbp);
278 #endif /* !_KERNEL */
280 #endif /* !_SYS_AIO_H_ */