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ltsleep.c revision 1.6.10.4 
      1 /*	$NetBSD: ltsleep.c,v 1.6.10.4 2010/03/11 15:04:38 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
      5  *
      6  * Development of this software was supported by the
      7  * Finnish Cultural Foundation.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     19  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     21  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 /*
     32  * Emulate the prehistoric tsleep-style kernel interfaces.  We assume
     33  * only code under the biglock will be using this type of synchronization
     34  * and use the biglock as the cv interlock.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: ltsleep.c,v 1.6.10.4 2010/03/11 15:04:38 yamt Exp $");
     39 
     40 #include <sys/param.h>
     41 #include <sys/kernel.h>
     42 #include <sys/proc.h>
     43 #include <sys/queue.h>
     44 #include <sys/simplelock.h>
     45 
     46 #include <rump/rumpuser.h>
     47 
     48 #include "rump_private.h"
     49 
     50 struct ltsleeper {
     51 	wchan_t id;
     52 	struct rumpuser_cv *cv;
     53 	LIST_ENTRY(ltsleeper) entries;
     54 };
     55 
     56 static LIST_HEAD(, ltsleeper) sleepers = LIST_HEAD_INITIALIZER(sleepers);
     57 
     58 static int
     59 sleeper(struct ltsleeper *ltsp, int timo)
     60 {
     61 	struct timespec ts, ticks;
     62 	int rv, nlocks;
     63 
     64 	LIST_INSERT_HEAD(&sleepers, ltsp, entries);
     65 	kernel_unlock_allbutone(&nlocks);
     66 
     67 	/* protected by biglock */
     68 	if (timo) {
     69 		/*
     70 		 * Calculate wakeup-time.
     71 		 * XXX: should assert nanotime() does not block,
     72 		 * i.e. yield the cpu and/or biglock.
     73 		 */
     74 		ticks.tv_sec = timo / hz;
     75 		ticks.tv_nsec = (timo % hz) * (1000000000/hz);
     76 		nanotime(&ts);
     77 		timespecadd(&ts, &ticks, &ts);
     78 
     79 		if (rumpuser_cv_timedwait(ltsp->cv, rump_giantlock,
     80 		    ts.tv_sec, ts.tv_nsec) == 0)
     81 			rv = 0;
     82 		else
     83 			rv = EWOULDBLOCK;
     84 	} else {
     85 		rumpuser_cv_wait(ltsp->cv, rump_giantlock);
     86 		rv = 0;
     87 	}
     88 
     89 	LIST_REMOVE(ltsp, entries);
     90 	rumpuser_cv_destroy(ltsp->cv);
     91 	kernel_ununlock_allbutone(nlocks);
     92 
     93 	return rv;
     94 }
     95 
     96 int
     97 ltsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo,
     98 	volatile struct simplelock *slock)
     99 {
    100 	struct ltsleeper lts;
    101 	int rv;
    102 
    103 	lts.id = ident;
    104 	rumpuser_cv_init(&lts.cv);
    105 
    106 	if (slock)
    107 		simple_unlock(slock);
    108 
    109 	rv = sleeper(&lts, timo);
    110 
    111 	if (slock && (prio & PNORELOCK) == 0)
    112 		simple_lock(slock);
    113 
    114 	return rv;
    115 }
    116 
    117 int
    118 mtsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo,
    119 	kmutex_t *lock)
    120 {
    121 	struct ltsleeper lts;
    122 	int rv;
    123 
    124 	lts.id = ident;
    125 	rumpuser_cv_init(&lts.cv);
    126 
    127 	mutex_exit(lock);
    128 
    129 	rv = sleeper(&lts, timo);
    130 
    131 	if ((prio & PNORELOCK) == 0)
    132 		mutex_enter(lock);
    133 
    134 	return rv;
    135 }
    136 
    137 static void
    138 do_wakeup(wchan_t ident, void (*wakeupfn)(struct rumpuser_cv *))
    139 {
    140 	struct ltsleeper *ltsp;
    141 
    142 	KASSERT(kernel_biglocked());
    143 	LIST_FOREACH(ltsp, &sleepers, entries) {
    144 		if (ltsp->id == ident) {
    145 			wakeupfn(ltsp->cv);
    146 		}
    147 	}
    148 }
    149 
    150 void
    151 wakeup(wchan_t ident)
    152 {
    153 
    154 	do_wakeup(ident, rumpuser_cv_broadcast);
    155 }
    156 
    157 void
    158 wakeup_one(wchan_t ident)
    159 {
    160 
    161 	do_wakeup(ident, rumpuser_cv_signal);
    162 }
    163