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sleepq.c revision 1.21 
      1 /*	$NetBSD: sleepq.c,v 1.21 2020/11/01 20:58:38 christos 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 1.21 2020/11/01 20:58:38 christos 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-sys/kern.h>
     41 
     42 syncobj_t sleep_syncobj;
     43 
     44 void
     45 sleepq_init(sleepq_t *sq)
     46 {
     47 
     48 	LIST_INIT(sq);
     49 	cv_init(&sq->sq_cv, "sleepq");
     50 }
     51 
     52 void
     53 sleepq_destroy(sleepq_t *sq)
     54 {
     55 
     56 	cv_destroy(&sq->sq_cv);
     57 }
     58 
     59 void
     60 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob,
     61     bool catch_p)
     62 {
     63 	struct lwp *l = curlwp;
     64 
     65 	l->l_wchan = wc;
     66 	l->l_wmesg = wmsg;
     67 	l->l_sleepq = sq;
     68 	LIST_INSERT_HEAD(sq, l, l_sleepchain);
     69 }
     70 
     71 int
     72 sleepq_block(int timo, bool catch)
     73 {
     74 	struct lwp *l = curlwp;
     75 	int error = 0;
     76 	kmutex_t *mp = l->l_mutex;
     77 	int biglocks = l->l_biglocks;
     78 
     79 	while (l->l_wchan) {
     80 		l->l_mutex = mp; /* keep sleepq lock until woken up */
     81 		error = cv_timedwait(&l->l_sleepq->sq_cv, mp, timo);
     82 		if (error == EWOULDBLOCK || error == EINTR) {
     83 			if (l->l_wchan) {
     84 				LIST_REMOVE(l, l_sleepchain);
     85 				l->l_wchan = NULL;
     86 				l->l_wmesg = NULL;
     87 			}
     88 		}
     89 	}
     90 	mutex_spin_exit(mp);
     91 
     92 	if (biglocks)
     93 		KERNEL_LOCK(biglocks, curlwp);
     94 
     95 	return error;
     96 }
     97 
     98 void
     99 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp)
    100 {
    101 	struct lwp *l, *l_next;
    102 	bool found = false;
    103 
    104 	for (l = LIST_FIRST(sq); l; l = l_next) {
    105 		l_next = LIST_NEXT(l, l_sleepchain);
    106 		if (l->l_wchan == wchan) {
    107 			found = true;
    108 			l->l_wchan = NULL;
    109 			l->l_wmesg = NULL;
    110 			LIST_REMOVE(l, l_sleepchain);
    111 			if (--expected == 0)
    112 				break;
    113 		}
    114 	}
    115 	if (found)
    116 		cv_broadcast(&sq->sq_cv);
    117 
    118 	mutex_spin_exit(mp);
    119 }
    120 
    121 void
    122 sleepq_unsleep(struct lwp *l, bool cleanup)
    123 {
    124 
    125 	l->l_wchan = NULL;
    126 	l->l_wmesg = NULL;
    127 	LIST_REMOVE(l, l_sleepchain);
    128 	cv_broadcast(&l->l_sleepq->sq_cv);
    129 
    130 	if (cleanup) {
    131 		mutex_spin_exit(l->l_mutex);
    132 	}
    133 }
    134 
    135 /*
    136  * Thread scheduler handles priorities.  Therefore no action here.
    137  * (maybe do something if we're deperate?)
    138  */
    139 void
    140 sleepq_changepri(struct lwp *l, pri_t pri)
    141 {
    142 
    143 }
    144 
    145 void
    146 sleepq_lendpri(struct lwp *l, pri_t pri)
    147 {
    148 
    149 }
    150 
    151 struct lwp *
    152 syncobj_noowner(wchan_t wc)
    153 {
    154 
    155 	return NULL;
    156 }
    157 
    158 void
    159 lwp_unlock_to(struct lwp *l, kmutex_t *new)
    160 {
    161 	kmutex_t *old;
    162 
    163 	KASSERT(mutex_owned(l->l_mutex));
    164 
    165 	old = l->l_mutex;
    166 	membar_exit();
    167 	l->l_mutex = new;
    168 	mutex_spin_exit(old);
    169 }
    170