completion.h revision 1.3.2.2
1 1.3.2.2 rmind /* $NetBSD: completion.h,v 1.3.2.2 2014/05/18 17:45:53 rmind Exp $ */ 2 1.3.2.2 rmind 3 1.3.2.2 rmind /*- 4 1.3.2.2 rmind * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 1.3.2.2 rmind * All rights reserved. 6 1.3.2.2 rmind * 7 1.3.2.2 rmind * This code is derived from software contributed to The NetBSD Foundation 8 1.3.2.2 rmind * by Taylor R. Campbell. 9 1.3.2.2 rmind * 10 1.3.2.2 rmind * Redistribution and use in source and binary forms, with or without 11 1.3.2.2 rmind * modification, are permitted provided that the following conditions 12 1.3.2.2 rmind * are met: 13 1.3.2.2 rmind * 1. Redistributions of source code must retain the above copyright 14 1.3.2.2 rmind * notice, this list of conditions and the following disclaimer. 15 1.3.2.2 rmind * 2. Redistributions in binary form must reproduce the above copyright 16 1.3.2.2 rmind * notice, this list of conditions and the following disclaimer in the 17 1.3.2.2 rmind * documentation and/or other materials provided with the distribution. 18 1.3.2.2 rmind * 19 1.3.2.2 rmind * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 1.3.2.2 rmind * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 1.3.2.2 rmind * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 1.3.2.2 rmind * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 1.3.2.2 rmind * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 1.3.2.2 rmind * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 1.3.2.2 rmind * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 1.3.2.2 rmind * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 1.3.2.2 rmind * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 1.3.2.2 rmind * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 1.3.2.2 rmind * POSSIBILITY OF SUCH DAMAGE. 30 1.3.2.2 rmind */ 31 1.3.2.2 rmind 32 1.3.2.2 rmind #ifndef _LINUX_COMPLETION_H_ 33 1.3.2.2 rmind #define _LINUX_COMPLETION_H_ 34 1.3.2.2 rmind 35 1.3.2.2 rmind #include <sys/types.h> 36 1.3.2.2 rmind #include <sys/condvar.h> 37 1.3.2.2 rmind #include <sys/mutex.h> 38 1.3.2.2 rmind 39 1.3.2.2 rmind #include <machine/limits.h> 40 1.3.2.2 rmind 41 1.3.2.2 rmind #include <linux/errno.h> 42 1.3.2.2 rmind 43 1.3.2.2 rmind struct completion { 44 1.3.2.2 rmind kmutex_t c_lock; 45 1.3.2.2 rmind kcondvar_t c_cv; 46 1.3.2.2 rmind 47 1.3.2.2 rmind /* 48 1.3.2.2 rmind * c_done is either 49 1.3.2.2 rmind * 50 1.3.2.2 rmind * . -1, meaning it's open season and we're done for good and 51 1.3.2.2 rmind * nobody need wait any more; 52 1.3.2.2 rmind * 53 1.3.2.2 rmind * . 0, meaning nothing is done, so waiters must block; or 54 1.3.2.2 rmind * 55 1.3.2.2 rmind * . a positive integer, meaning that many waiters can 56 1.3.2.2 rmind * proceed before further waiters must block. 57 1.3.2.2 rmind * 58 1.3.2.2 rmind * Negative values other than -1 are not allowed. 59 1.3.2.2 rmind */ 60 1.3.2.2 rmind int c_done; 61 1.3.2.2 rmind }; 62 1.3.2.2 rmind 63 1.3.2.2 rmind /* 64 1.3.2.2 rmind * Initialize a new completion object. 65 1.3.2.2 rmind */ 66 1.3.2.2 rmind static inline void 67 1.3.2.2 rmind init_completion(struct completion *completion) 68 1.3.2.2 rmind { 69 1.3.2.2 rmind 70 1.3.2.2 rmind mutex_init(&completion->c_lock, MUTEX_DEFAULT, IPL_VM); 71 1.3.2.2 rmind cv_init(&completion->c_cv, "lnxcmplt"); 72 1.3.2.2 rmind completion->c_done = 0; 73 1.3.2.2 rmind } 74 1.3.2.2 rmind 75 1.3.2.2 rmind /* 76 1.3.2.2 rmind * Destroy a completion object. 77 1.3.2.2 rmind */ 78 1.3.2.2 rmind static inline void 79 1.3.2.2 rmind destroy_completion(struct completion *completion) 80 1.3.2.2 rmind { 81 1.3.2.2 rmind KASSERT(!cv_has_waiters(&completion->c_cv)); 82 1.3.2.2 rmind cv_destroy(&completion->c_cv); 83 1.3.2.2 rmind mutex_destroy(&completion->c_lock); 84 1.3.2.2 rmind } 85 1.3.2.2 rmind 86 1.3.2.2 rmind /* 87 1.3.2.2 rmind * Notify one waiter of completion, but not any future ones. 88 1.3.2.2 rmind */ 89 1.3.2.2 rmind static inline void 90 1.3.2.2 rmind complete(struct completion *completion) 91 1.3.2.2 rmind { 92 1.3.2.2 rmind 93 1.3.2.2 rmind mutex_enter(&completion->c_lock); 94 1.3.2.2 rmind 95 1.3.2.2 rmind /* If it's not open season, wake one waiter. */ 96 1.3.2.2 rmind if (completion->c_done >= 0) { 97 1.3.2.2 rmind KASSERT(completion->c_done < INT_MAX); /* XXX check */ 98 1.3.2.2 rmind completion->c_done++; 99 1.3.2.2 rmind cv_signal(&completion->c_cv); 100 1.3.2.2 rmind } else { 101 1.3.2.2 rmind KASSERT(completion->c_done == -1); 102 1.3.2.2 rmind } 103 1.3.2.2 rmind 104 1.3.2.2 rmind mutex_exit(&completion->c_lock); 105 1.3.2.2 rmind } 106 1.3.2.2 rmind 107 1.3.2.2 rmind /* 108 1.3.2.2 rmind * Notify all waiters, present and future (until INIT_COMPLETION), of 109 1.3.2.2 rmind * completion. 110 1.3.2.2 rmind */ 111 1.3.2.2 rmind static inline void 112 1.3.2.2 rmind complete_all(struct completion *completion) 113 1.3.2.2 rmind { 114 1.3.2.2 rmind 115 1.3.2.2 rmind mutex_enter(&completion->c_lock); 116 1.3.2.2 rmind 117 1.3.2.2 rmind /* If it's not open season, make it open season and wake everyone. */ 118 1.3.2.2 rmind if (completion->c_done >= 0) { 119 1.3.2.2 rmind completion->c_done = -1; 120 1.3.2.2 rmind cv_broadcast(&completion->c_cv); 121 1.3.2.2 rmind } else { 122 1.3.2.2 rmind KASSERT(completion->c_done == -1); 123 1.3.2.2 rmind } 124 1.3.2.2 rmind 125 1.3.2.2 rmind mutex_exit(&completion->c_lock); 126 1.3.2.2 rmind } 127 1.3.2.2 rmind 128 1.3.2.2 rmind /* 129 1.3.2.2 rmind * Reverse the effect of complete_all so that subsequent waiters block 130 1.3.2.2 rmind * until someone calls complete or complete_all. 131 1.3.2.2 rmind * 132 1.3.2.2 rmind * This operation is very different from its lowercase counterpart. 133 1.3.2.2 rmind * 134 1.3.2.2 rmind * For some reason this works on the completion object itself, not on a 135 1.3.2.2 rmind * pointer thereto, so it must be a macro. 136 1.3.2.2 rmind */ 137 1.3.2.2 rmind #define INIT_COMPLETION(COMPLETION) INIT_COMPLETION_blorp(&(COMPLETION)) 138 1.3.2.2 rmind 139 1.3.2.2 rmind static inline void 140 1.3.2.2 rmind INIT_COMPLETION_blorp(struct completion *completion) 141 1.3.2.2 rmind { 142 1.3.2.2 rmind 143 1.3.2.2 rmind mutex_enter(&completion->c_lock); 144 1.3.2.2 rmind completion->c_done = 0; 145 1.3.2.2 rmind /* No notify -- waiters are interested only in nonzero values. */ 146 1.3.2.2 rmind mutex_exit(&completion->c_lock); 147 1.3.2.2 rmind } 148 1.3.2.2 rmind 149 1.3.2.2 rmind static inline void 150 1.3.2.2 rmind _completion_claim(struct completion *completion) 151 1.3.2.2 rmind { 152 1.3.2.2 rmind 153 1.3.2.2 rmind KASSERT(mutex_owned(&completion->c_lock)); 154 1.3.2.2 rmind KASSERT(completion->c_done != 0); 155 1.3.2.2 rmind if (completion->c_done > 0) 156 1.3.2.2 rmind completion->c_done--; 157 1.3.2.2 rmind else 158 1.3.2.2 rmind KASSERT(completion->c_done == -1); 159 1.3.2.2 rmind } 160 1.3.2.2 rmind 161 1.3.2.2 rmind /* 162 1.3.2.2 rmind * Wait interruptibly with a timeout for someone to call complete or 163 1.3.2.2 rmind * complete_all. 164 1.3.2.2 rmind */ 165 1.3.2.2 rmind static inline int 166 1.3.2.2 rmind wait_for_completion_interruptible_timeout(struct completion *completion, 167 1.3.2.2 rmind unsigned long ticks) 168 1.3.2.2 rmind { 169 1.3.2.2 rmind /* XXX Arithmetic overflow...? */ 170 1.3.2.2 rmind unsigned int start = hardclock_ticks, now; 171 1.3.2.2 rmind int error; 172 1.3.2.2 rmind 173 1.3.2.2 rmind mutex_enter(&completion->c_lock); 174 1.3.2.2 rmind 175 1.3.2.2 rmind /* Wait until c_done is nonzero. */ 176 1.3.2.2 rmind while (completion->c_done == 0) { 177 1.3.2.2 rmind error = cv_timedwait_sig(&completion->c_cv, 178 1.3.2.2 rmind &completion->c_lock, ticks); 179 1.3.2.2 rmind if (error) 180 1.3.2.2 rmind goto out; 181 1.3.2.2 rmind now = hardclock_ticks; 182 1.3.2.2 rmind if (ticks < (now - start)) { 183 1.3.2.2 rmind error = EWOULDBLOCK; 184 1.3.2.2 rmind goto out; 185 1.3.2.2 rmind } 186 1.3.2.2 rmind ticks -= (now - start); 187 1.3.2.2 rmind start = now; 188 1.3.2.2 rmind } 189 1.3.2.2 rmind 190 1.3.2.2 rmind /* Success! */ 191 1.3.2.2 rmind _completion_claim(completion); 192 1.3.2.2 rmind error = 0; 193 1.3.2.2 rmind 194 1.3.2.2 rmind out: mutex_exit(&completion->c_lock); 195 1.3.2.2 rmind if (error == EWOULDBLOCK) { 196 1.3.2.2 rmind return 0; 197 1.3.2.2 rmind } else if ((error == EINTR) || (error == ERESTART)) { 198 1.3.2.2 rmind return -ERESTARTSYS; 199 1.3.2.2 rmind } else { 200 1.3.2.2 rmind KASSERTMSG((error == 0), "error = %d", error); 201 1.3.2.2 rmind return ticks; 202 1.3.2.2 rmind } 203 1.3.2.2 rmind } 204 1.3.2.2 rmind 205 1.3.2.2 rmind /* 206 1.3.2.2 rmind * Wait interruptibly for someone to call complete or complete_all. 207 1.3.2.2 rmind */ 208 1.3.2.2 rmind static inline int 209 1.3.2.2 rmind wait_for_completion_interruptible(struct completion *completion) 210 1.3.2.2 rmind { 211 1.3.2.2 rmind int error; 212 1.3.2.2 rmind 213 1.3.2.2 rmind mutex_enter(&completion->c_lock); 214 1.3.2.2 rmind 215 1.3.2.2 rmind /* Wait until c_done is nonzero. */ 216 1.3.2.2 rmind while (completion->c_done == 0) { 217 1.3.2.2 rmind error = cv_wait_sig(&completion->c_cv, &completion->c_lock); 218 1.3.2.2 rmind if (error) 219 1.3.2.2 rmind goto out; 220 1.3.2.2 rmind } 221 1.3.2.2 rmind 222 1.3.2.2 rmind /* Success! */ 223 1.3.2.2 rmind _completion_claim(completion); 224 1.3.2.2 rmind error = 0; 225 1.3.2.2 rmind 226 1.3.2.2 rmind out: mutex_exit(&completion->c_lock); 227 1.3.2.2 rmind if ((error == EINTR) || (error == ERESTART)) 228 1.3.2.2 rmind error = -ERESTARTSYS; 229 1.3.2.2 rmind return error; 230 1.3.2.2 rmind } 231 1.3.2.2 rmind 232 1.3.2.2 rmind /* 233 1.3.2.2 rmind * Wait uninterruptibly, except by SIGKILL, for someone to call 234 1.3.2.2 rmind * complete or complete_all. 235 1.3.2.2 rmind * 236 1.3.2.2 rmind * XXX In this implementation, any signal will actually wake us, not 237 1.3.2.2 rmind * just SIGKILL. 238 1.3.2.2 rmind */ 239 1.3.2.2 rmind static inline int 240 1.3.2.2 rmind wait_for_completion_killable(struct completion *completion) 241 1.3.2.2 rmind { 242 1.3.2.2 rmind 243 1.3.2.2 rmind return wait_for_completion_interruptible(completion); 244 1.3.2.2 rmind } 245 1.3.2.2 rmind 246 1.3.2.2 rmind /* 247 1.3.2.2 rmind * Try to claim a completion immediately. Return true on success, false 248 1.3.2.2 rmind * if it would block. 249 1.3.2.2 rmind */ 250 1.3.2.2 rmind static inline bool 251 1.3.2.2 rmind try_wait_for_completion(struct completion *completion) 252 1.3.2.2 rmind { 253 1.3.2.2 rmind bool ok; 254 1.3.2.2 rmind 255 1.3.2.2 rmind mutex_enter(&completion->c_lock); 256 1.3.2.2 rmind if (completion->c_done == 0) { 257 1.3.2.2 rmind ok = false; 258 1.3.2.2 rmind } else { 259 1.3.2.2 rmind _completion_claim(completion); 260 1.3.2.2 rmind ok = true; 261 1.3.2.2 rmind } 262 1.3.2.2 rmind mutex_exit(&completion->c_lock); 263 1.3.2.2 rmind 264 1.3.2.2 rmind return ok; 265 1.3.2.2 rmind } 266 1.3.2.2 rmind 267 1.3.2.2 rmind #endif /* _LINUX_COMPLETION_H_ */ 268
Indexes created Tue Sep 30 20:09:53 GMT 2025