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1113 palkovsky 1 
/*
4516 jermar 2 
 * Copyright (c) 2009 Jakub Jermar
1113 palkovsky 3 
 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1719 decky 29 
/** @addtogroup libc
1653 cejka 30 
 * @{
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 */
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/** @file
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 */
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4516 jermar 35 
#include <fibril_sync.h>
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#include <fibril.h>
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#include <async.h>
4509 decky 38 
#include <adt/list.h>
1392 palkovsky 39 
#include <futex.h>
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#include <assert.h>
1113 palkovsky 41 
 
4516 jermar 42 
void fibril_mutex_initialize(fibril_mutex_t *fm)
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{
4516 jermar 44 
    fm->counter = 1;
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    list_initialize(&fm->waiters);
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}
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4516 jermar 48 
void fibril_mutex_lock(fibril_mutex_t *fm)
1129 palkovsky 49 
{
4516 jermar 50 
    futex_down(&async_futex);
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    if (fm->counter-- <= 0) {
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        fibril_t *f = (fibril_t *) fibril_get_id();
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        list_append(&f->link, &fm->waiters);
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        fibril_switch(FIBRIL_TO_MANAGER);
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    } else {
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        futex_up(&async_futex);
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    }
1129 palkovsky 58 
}
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4516 jermar 60 
bool fibril_mutex_trylock(fibril_mutex_t *fm)
1113 palkovsky 61 
{
4516 jermar 62 
    bool locked = false;
1392 palkovsky 63 
 
4516 jermar 64 
    futex_down(&async_futex);
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    if (fm->counter > 0) {
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        fm->counter--;
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        locked = true;
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    }
4516 jermar 69 
    futex_up(&async_futex);
1610 palkovsky 70 
 
4516 jermar 71 
    return locked;
1113 palkovsky 72 
}
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4516 jermar 74 
void fibril_mutex_unlock(fibril_mutex_t *fm)
1113 palkovsky 75 
{
4516 jermar 76 
    futex_down(&async_futex);
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    assert(fm->counter <= 0);
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    if (fm->counter++ < 0) {
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        link_t *tmp;
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        fibril_t *f;
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        assert(!list_empty(&fm->waiters));
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        tmp = fm->waiters.next;
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        f = list_get_instance(tmp, fibril_t, link);
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        list_remove(&f->link);
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        fibril_add_ready((fid_t) f);
1113 palkovsky 87 
    }
4516 jermar 88 
    futex_up(&async_futex);
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}
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4516 jermar 91 
void fibril_rwlock_initialize(fibril_rwlock_t *frw)
1392 palkovsky 92 
{
4526 jermar 93 
    frw->writers = 0;
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    frw->readers = 0;
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    list_initialize(&frw->waiters);
1392 palkovsky 96 
}
1113 palkovsky 97 
 
4516 jermar 98 
void fibril_rwlock_read_lock(fibril_rwlock_t *frw)
1392 palkovsky 99 
{
4526 jermar 100 
    futex_down(&async_futex);
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    if (frw->writers) {
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        fibril_t *f = (fibril_t *) fibril_get_id();
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        f->flags &= ~FIBRIL_WRITER;
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        list_append(&f->link, &frw->waiters);
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        fibril_switch(FIBRIL_TO_MANAGER);
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    } else {
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        frw->readers++;
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        futex_up(&async_futex);
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    }
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}
1392 palkovsky 111 
 
4516 jermar 112 
void fibril_rwlock_write_lock(fibril_rwlock_t *frw)
1392 palkovsky 113 
{
4526 jermar 114 
    futex_down(&async_futex);
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    if (frw->writers || frw->readers) {
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        fibril_t *f = (fibril_t *) fibril_get_id();
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        f->flags |= FIBRIL_WRITER;
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        list_append(&f->link, &frw->waiters);
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        fibril_switch(FIBRIL_TO_MANAGER);
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    } else {
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        frw->writers++;
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        futex_up(&async_futex);
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    }
1392 palkovsky 124 
}
1427 palkovsky 125 
 
4526 jermar 126 
static void _fibril_rwlock_common_unlock(fibril_rwlock_t *frw)
127 
{
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    futex_down(&async_futex);
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    assert(frw->readers || (frw->writers == 1));
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    if (frw->readers) {
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        if (--frw->readers)
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            goto out;
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    } else {
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        frw->writers--;
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    }
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137 
    assert(!frw->readers && !frw->writers);
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139 
    while (!list_empty(&frw->waiters)) {
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        link_t *tmp = frw->waiters.next;
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        fibril_t *f = list_get_instance(tmp, fibril_t, link);
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        if (f->flags & FIBRIL_WRITER) {
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            if (frw->readers)
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                break;
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            list_remove(&f->link);
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            fibril_add_ready((fid_t) f);
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            frw->writers++;
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            break;
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        } else {
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            list_remove(&f->link);
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            fibril_add_ready((fid_t) f);
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            frw->readers++;
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        }
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    }
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out:
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    futex_up(&async_futex);
158 
}
159 
 
4516 jermar 160 
void fibril_rwlock_read_unlock(fibril_rwlock_t *frw)
1427 palkovsky 161 
{
4526 jermar 162 
    _fibril_rwlock_common_unlock(frw);
1427 palkovsky 163 
}
1610 palkovsky 164 
 
4516 jermar 165 
void fibril_rwlock_write_unlock(fibril_rwlock_t *frw)
1610 palkovsky 166 
{
4526 jermar 167 
    _fibril_rwlock_common_unlock(frw);
1610 palkovsky 168 
}
169 
 
1719 decky 170 
/** @}
1653 cejka 171 
 */