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>
33 * Returned by aio_cancel:
35 #define AIO_CANCELED 0x1
36 #define AIO_NOTCANCELED 0x2
37 #define AIO_ALLDONE 0x3
53 #define LIO_NOWAIT 0x0
57 * Maximum number of operations in a single lio_listio call
59 #define AIO_LISTIO_MAX 16
63 /* Default values of tunables for the AIO worker pool. */
66 #define MAX_AIO_PROCS 32
69 #ifndef TARGET_AIO_PROCS
70 #define TARGET_AIO_PROCS 4
73 #ifndef AIOD_LIFETIME_DEFAULT
74 #define AIOD_LIFETIME_DEFAULT (30 * hz)
80 * Private members for aiocb -- don't access
83 struct __aiocb_private {
92 typedef 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 */
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 */
107 typedef void aio_cancel_fn_t(struct kaiocb *);
108 typedef void aio_handle_fn_t(struct kaiocb *);
111 * Kernel version of an I/O control block.
114 * * - need not protected
115 * a - locked by kaioinfo lock
116 * b - locked by backend lock
117 * c - locked by aio_job_mtx
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 int npages; /* (*) number of pages */
144 struct vm_page **pages; /* (*) */
146 struct { /* fsync() requests */
147 int pending; /* (a) number of pending I/O */
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.
168 * When queueing a request somewhere such that it can be cancelled, the
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.
177 * When dequeueing a request to service it or hand it off to somewhere else,
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.
186 * The cancel routine should:
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().
195 bool aio_cancel_cleared(struct kaiocb *job);
196 void aio_cancel(struct kaiocb *job);
197 bool aio_clear_cancel_function(struct kaiocb *job);
198 void aio_complete(struct kaiocb *job, long status, int error);
199 void aio_schedule(struct kaiocb *job, aio_handle_fn_t *func);
200 bool aio_set_cancel_function(struct kaiocb *job, aio_cancel_fn_t *func);
201 void aio_switch_vmspace(struct kaiocb *job);
209 * Asynchronously read from a file
211 int aio_read(struct aiocb *);
214 * Asynchronously write to file
216 int aio_write(struct aiocb *);
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.
224 int lio_listio(int, struct aiocb *__restrict const *__restrict, int,
228 * Get completion status
229 * returns EINPROGRESS until I/O is complete.
230 * this routine does not block.
232 int aio_error(const struct aiocb *);
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.
240 ssize_t aio_return(struct aiocb *);
245 int aio_cancel(int, struct aiocb *);
248 * Suspend until all specified I/O or timeout is complete.
250 int aio_suspend(const struct aiocb * const[], int, const struct timespec *);
255 int aio_mlock(struct aiocb *);
258 ssize_t aio_waitcomplete(struct aiocb **, struct timespec *);
261 int aio_fsync(int op, struct aiocb *aiocbp);
264 #endif /* !_KERNEL */
266 #endif /* !_SYS_AIO_H_ */