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sleepq.c revision 1.17 
      1 /*	$NetBSD: sleepq.c,v 1.17 2016/01/26 23:12:18 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 1.17 2016/01/26 23:12:18 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-sys/kern.h>
     41 
     42 syncobj_t sleep_syncobj;
     43 static kcondvar_t sq_cv;
     44 
     45 static int
     46 sqinit1(void)
     47 {
     48 
     49 	cv_init(&sq_cv, "sleepq");
     50 
     51 	return 0;
     52 }
     53 
     54 void
     55 sleepq_init(sleepq_t *sq)
     56 {
     57 	static ONCE_DECL(sqctl);
     58 
     59 	RUN_ONCE(&sqctl, sqinit1);
     60 
     61 	TAILQ_INIT(sq);
     62 }
     63 
     64 void
     65 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob)
     66 {
     67 	struct lwp *l = curlwp;
     68 
     69 	l->l_wchan = wc;
     70 	l->l_wmesg = wmsg;
     71 	l->l_sleepq = sq;
     72 	TAILQ_INSERT_TAIL(sq, l, l_sleepchain);
     73 }
     74 
     75 int
     76 sleepq_block(int timo, bool catch)
     77 {
     78 	struct lwp *l = curlwp;
     79 	int error = 0;
     80 	kmutex_t *mp = l->l_mutex;
     81 	int biglocks = l->l_biglocks;
     82 
     83 	while (l->l_wchan) {
     84 		l->l_mutex = mp; /* keep sleepq lock until woken up */
     85 		error = cv_timedwait(&sq_cv, mp, timo);
     86 		if (error == EWOULDBLOCK || error == EINTR) {
     87 			if (l->l_wchan) {
     88 				TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
     89 				l->l_wchan = NULL;
     90 				l->l_wmesg = NULL;
     91 			}
     92 		}
     93 	}
     94 	mutex_spin_exit(mp);
     95 
     96 	if (biglocks)
     97 		KERNEL_LOCK(biglocks, curlwp);
     98 
     99 	return error;
    100 }
    101 
    102 void
    103 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp)
    104 {
    105 	struct lwp *l, *l_next;
    106 	bool found = false;
    107 
    108 	for (l = TAILQ_FIRST(sq); l; l = l_next) {
    109 		l_next = TAILQ_NEXT(l, l_sleepchain);
    110 		if (l->l_wchan == wchan) {
    111 			found = true;
    112 			l->l_wchan = NULL;
    113 			l->l_wmesg = NULL;
    114 			TAILQ_REMOVE(sq, l, l_sleepchain);
    115 			if (--expected == 0)
    116 				break;
    117 		}
    118 	}
    119 	if (found)
    120 		cv_broadcast(&sq_cv);
    121 
    122 	mutex_spin_exit(mp);
    123 }
    124 
    125 void
    126 sleepq_unsleep(struct lwp *l, bool cleanup)
    127 {
    128 
    129 	l->l_wchan = NULL;
    130 	l->l_wmesg = NULL;
    131 	TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
    132 	cv_broadcast(&sq_cv);
    133 
    134 	if (cleanup) {
    135 		mutex_spin_exit(l->l_mutex);
    136 	}
    137 }
    138 
    139 /*
    140  * Thread scheduler handles priorities.  Therefore no action here.
    141  * (maybe do something if we're deperate?)
    142  */
    143 void
    144 sleepq_changepri(struct lwp *l, pri_t pri)
    145 {
    146 
    147 }
    148 
    149 void
    150 sleepq_lendpri(struct lwp *l, pri_t pri)
    151 {
    152 
    153 }
    154 
    155 struct lwp *
    156 syncobj_noowner(wchan_t wc)
    157 {
    158 
    159 	return NULL;
    160 }
    161 
    162 void
    163 lwp_unlock_to(struct lwp *l, kmutex_t *new)
    164 {
    165 	kmutex_t *old;
    166 
    167 	KASSERT(mutex_owned(l->l_mutex));
    168 
    169 	old = l->l_mutex;
    170 	membar_exit();
    171 	l->l_mutex = new;
    172 	mutex_spin_exit(old);
    173 }
    174