1 /* $NetBSD: sleepq.c,v 1.6 2009/11/17 15:23:42 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 1.6 2009/11/17 15:23:42 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 39 #include "rump_private.h" 40 41 /* 42 * Flimsy and minimalistic sleepq implementation. This is implemented 43 * only for the use of callouts in kern_timeout.c. locking etc is 44 * completely incorrect, horrible, etc etc etc. 45 */ 46 47 syncobj_t sleep_syncobj; 48 static kcondvar_t sq_cv; 49 50 static int 51 sqinit1(void) 52 { 53 54 cv_init(&sq_cv, "sleepq"); 55 56 return 0; 57 } 58 59 void 60 sleepq_init(sleepq_t *sq) 61 { 62 ONCE_DECL(sqctl); 63 64 RUN_ONCE(&sqctl, sqinit1); 65 66 TAILQ_INIT(sq); 67 } 68 69 void 70 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob) 71 { 72 struct lwp *l = curlwp; 73 74 l->l_wchan = wc; 75 l->l_sleepq = sq; 76 TAILQ_INSERT_TAIL(sq, l, l_sleepchain); 77 } 78 79 int 80 sleepq_block(int timo, bool catch) 81 { 82 struct lwp *l = curlwp; 83 int error = 0; 84 kmutex_t *mp = l->l_mutex; 85 int biglocks = l->l_biglocks; 86 87 while (l->l_wchan) { 88 if ((error=cv_timedwait(&sq_cv, mp, timo)) == EWOULDBLOCK) { 89 TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain); 90 l->l_wchan = NULL; 91 } 92 } 93 mutex_spin_exit(mp); 94 95 if (biglocks) 96 KERNEL_LOCK(biglocks, curlwp); 97 98 return error; 99 } 100 101 lwp_t * 102 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp) 103 { 104 struct lwp *l, *l_next; 105 bool found = false; 106 107 if (__predict_false(expected != -1)) 108 panic("sleepq_wake: \"expected\" not supported"); 109 110 for (l = TAILQ_FIRST(sq); l; l = l_next) { 111 l_next = TAILQ_NEXT(l, l_sleepchain); 112 if (l->l_wchan == wchan) { 113 found = true; 114 l->l_wchan = NULL; 115 TAILQ_REMOVE(sq, l, l_sleepchain); 116 } 117 } 118 if (found) 119 cv_broadcast(&sq_cv); 120 121 mutex_spin_exit(mp); 122 return NULL; 123 } 124 125 void 126 sleepq_unsleep(struct lwp *l, bool cleanup) 127 { 128 129 l->l_wchan = NULL; 130 TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain); 131 cv_broadcast(&sq_cv); 132 133 if (cleanup) { 134 mutex_spin_exit(l->l_mutex); 135 } 136 } 137 138 /* 139 * Thread scheduler handles priorities. Therefore no action here. 140 * (maybe do something if we're deperate?) 141 */ 142 void 143 sleepq_changepri(struct lwp *l, pri_t pri) 144 { 145 146 } 147 148 void 149 sleepq_lendpri(struct lwp *l, pri_t pri) 150 { 151 152 } 153 154 struct lwp * 155 syncobj_noowner(wchan_t wc) 156 { 157 158 return NULL; 159 } 160 161 /* 162 * XXX: used only by callout, therefore here. should try to use 163 * one in kern_lwp directly. 164 */ 165 kmutex_t * 166 lwp_lock_retry(struct lwp *l, kmutex_t *old) 167 { 168 169 while (l->l_mutex != old) { 170 mutex_spin_exit(old); 171 old = l->l_mutex; 172 mutex_spin_enter(old); 173 } 174 return old; 175 } 176