1 /* $NetBSD: sleepq.c,v 1.11 2011/01/12 12:51:21 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2008 Antti Kantee. 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. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __KERNEL_RCSID(0, "$NetBSD: sleepq.c,v 1.11 2011/01/12 12:51:21 pooka Exp $"); 30 31 #include <sys/param.h> 32 #include <sys/condvar.h> 33 #include <sys/mutex.h> 34 #include <sys/once.h> 35 #include <sys/queue.h> 36 #include <sys/sleepq.h> 37 #include <sys/syncobj.h> 38 #include <sys/atomic.h> 39 40 #include "rump_private.h" 41 42 /* 43 * Flimsy and minimalistic sleepq implementation. This is implemented 44 * only for the use of callouts in kern_timeout.c. locking etc is 45 * completely incorrect, horrible, etc etc etc. 46 */ 47 48 syncobj_t sleep_syncobj; 49 static kcondvar_t sq_cv; 50 51 static int 52 sqinit1(void) 53 { 54 55 cv_init(&sq_cv, "sleepq"); 56 57 return 0; 58 } 59 60 void 61 sleepq_init(sleepq_t *sq) 62 { 63 ONCE_DECL(sqctl); 64 65 RUN_ONCE(&sqctl, sqinit1); 66 67 TAILQ_INIT(sq); 68 } 69 70 void 71 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob) 72 { 73 struct lwp *l = curlwp; 74 75 l->l_wchan = wc; 76 l->l_sleepq = sq; 77 TAILQ_INSERT_TAIL(sq, l, l_sleepchain); 78 } 79 80 int 81 sleepq_block(int timo, bool catch) 82 { 83 struct lwp *l = curlwp; 84 int error = 0; 85 kmutex_t *mp = l->l_mutex; 86 int biglocks = l->l_biglocks; 87 88 while (l->l_wchan) { 89 l->l_mutex = mp; 90 error = cv_timedwait(&sq_cv, mp, timo); 91 if (error == EWOULDBLOCK || error == EINTR) { 92 TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain); 93 l->l_wchan = NULL; 94 } 95 } 96 mutex_spin_exit(mp); 97 98 if (biglocks) 99 KERNEL_LOCK(biglocks, curlwp); 100 101 return error; 102 } 103 104 lwp_t * 105 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp) 106 { 107 struct lwp *l, *l_next; 108 bool found = false; 109 110 if (__predict_false(expected != -1)) 111 panic("sleepq_wake: \"expected\" not supported"); 112 113 for (l = TAILQ_FIRST(sq); l; l = l_next) { 114 l_next = TAILQ_NEXT(l, l_sleepchain); 115 if (l->l_wchan == wchan) { 116 found = true; 117 l->l_wchan = NULL; 118 l->l_mutex = NULL; 119 TAILQ_REMOVE(sq, l, l_sleepchain); 120 } 121 } 122 if (found) 123 cv_broadcast(&sq_cv); 124 125 mutex_spin_exit(mp); 126 return NULL; 127 } 128 129 void 130 sleepq_unsleep(struct lwp *l, bool cleanup) 131 { 132 133 l->l_wchan = NULL; 134 l->l_mutex = NULL; 135 TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain); 136 cv_broadcast(&sq_cv); 137 138 if (cleanup) { 139 mutex_spin_exit(l->l_mutex); 140 } 141 } 142 143 /* 144 * Thread scheduler handles priorities. Therefore no action here. 145 * (maybe do something if we're deperate?) 146 */ 147 void 148 sleepq_changepri(struct lwp *l, pri_t pri) 149 { 150 151 } 152 153 void 154 sleepq_lendpri(struct lwp *l, pri_t pri) 155 { 156 157 } 158 159 struct lwp * 160 syncobj_noowner(wchan_t wc) 161 { 162 163 return NULL; 164 } 165 166 void 167 lwp_unlock_to(struct lwp *l, kmutex_t *new) 168 { 169 kmutex_t *old; 170 171 KASSERT(mutex_owned(l->l_mutex)); 172 173 old = l->l_mutex; 174 membar_exit(); 175 l->l_mutex = new; 176 mutex_spin_exit(old); 177 } 178