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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <test.h>

#include <arch.h>

#include <atomic.h>

#include <print.h>

#include <proc/thread.h>

#include <arch/types.h>

#include <arch/context.h>

#include <context.h>

#include <panic.h>

#include <synch/waitq.h>

#include <synch/rwlock.h>

#include <synch/synch.h>

#include <synch/spinlock.h>

#define READERS     50

#define WRITERS     50

static rwlock_t rwlock;

SPINLOCK_INITIALIZE(lock);

static waitq_t can_start;

__u32 seed = 0xdeadbeef;

static __u32 random(__u32 max);

static void writer(void *arg);

static void reader(void *arg);

static void failed(void);

__u32 random(__u32 max)

{

    __u32 rc;

    spinlock_lock(&lock);  

    rc = seed % max;

    seed = (((seed<<2) ^ (seed>>2)) * 487) + rc;

    spinlock_unlock(&lock);

    return rc;

}

void writer(void *arg)

{

    int rc, to;

    waitq_sleep(&can_start);

    to = random(40000);

    printf("cpu%d, tid %d w+ (%d)\n", CPU->id, THREAD->tid, to);

    rc = rwlock_write_lock_timeout(&rwlock, to);

    if (SYNCH_FAILED(rc)) {

        printf("cpu%d, tid %d w!\n", CPU->id, THREAD->tid);

        return;

    };

    printf("cpu%d, tid %d w=\n", CPU->id, THREAD->tid);

    if (rwlock.readers_in) panic("Oops.");

    thread_usleep(random(1000000));

    if (rwlock.readers_in) panic("Oops."); 

    rwlock_write_unlock(&rwlock);

    printf("cpu%d, tid %d w-\n", CPU->id, THREAD->tid);

}

void reader(void *arg)

{

    int rc, to;

    waitq_sleep(&can_start);

    to = random(2000);

    printf("cpu%d, tid %d r+ (%d)\n", CPU->id, THREAD->tid, to);

    rc = rwlock_read_lock_timeout(&rwlock, to);

    if (SYNCH_FAILED(rc)) {

        printf("cpu%d, tid %d r!\n", CPU->id, THREAD->tid);

        return;

    }

    printf("cpu%d, tid %d r=\n", CPU->id, THREAD->tid);

    thread_usleep(30000);

    rwlock_read_unlock(&rwlock);

    printf("cpu%d, tid %d r-\n", CPU->id, THREAD->tid);    

}

void failed(void)

{

    printf("Test failed prematurely.\n");

    thread_exit();

}

void test(void)

{

    context_t ctx;

    __u32 i, k;

    printf("Read/write locks test #4\n");

    waitq_initialize(&can_start);

    rwlock_initialize(&rwlock);

    for (; ;) {

        thread_t *thrd;

        context_save(&ctx);

        printf("sp=%#X, readers_in=%d\n", ctx.sp, rwlock.readers_in);

        k = random(7) + 1;

        printf("Creating %d readers\n", k);

        for (i=0; i<k; i++) {

            thrd = thread_create(reader, NULL, TASK, 0, "reader");

            if (thrd)

                thread_ready(thrd);

            else

                failed();

        }

        k = random(5) + 1;

        printf("Creating %d writers\n", k);

        for (i=0; i<k; i++) {

            thrd = thread_create(writer, NULL, TASK, 0, "writer");

            if (thrd)

                thread_ready(thrd);

            else

                failed();

        }

        thread_usleep(20000);

        waitq_wakeup(&can_start, WAKEUP_ALL);

    }      

}