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