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rf_mcpair.c revision 1.2 
      1 /*	$NetBSD: rf_mcpair.c,v 1.2 1999/01/26 02:33:58 oster Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: Jim Zelenka
      7  *
      8  * Permission to use, copy, modify and distribute this software and
      9  * its documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie the
     26  * rights to redistribute these changes.
     27  */
     28 
     29 /* rf_mcpair.c
     30  * an mcpair is a structure containing a mutex and a condition variable.
     31  * it's used to block the current thread until some event occurs.
     32  */
     33 
     34 #include "rf_types.h"
     35 #include "rf_threadstuff.h"
     36 #include "rf_mcpair.h"
     37 #include "rf_debugMem.h"
     38 #include "rf_freelist.h"
     39 #include "rf_shutdown.h"
     40 
     41 #include <sys/proc.h>
     42 
     43 static RF_FreeList_t *rf_mcpair_freelist;
     44 
     45 #define RF_MAX_FREE_MCPAIR 128
     46 #define RF_MCPAIR_INC       16
     47 #define RF_MCPAIR_INITIAL   24
     48 
     49 static int init_mcpair(RF_MCPair_t *);
     50 static void clean_mcpair(RF_MCPair_t *);
     51 static void rf_ShutdownMCPair(void *);
     52 
     53 
     54 
     55 static int init_mcpair(t)
     56   RF_MCPair_t  *t;
     57 {
     58 	int rc;
     59 
     60 	rc = rf_mutex_init(&t->mutex);
     61 	if (rc) {
     62 		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
     63 			__LINE__, rc);
     64 		return(rc);
     65 	}
     66 	rc = rf_cond_init(&t->cond);
     67 	if (rc) {
     68 		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", __FILE__,
     69 			__LINE__, rc);
     70 		rf_mutex_destroy(&t->mutex);
     71 		return(rc);
     72 	}
     73 	return(0);
     74 }
     75 
     76 static void clean_mcpair(t)
     77   RF_MCPair_t  *t;
     78 {
     79 	rf_mutex_destroy(&t->mutex);
     80 	rf_cond_destroy(&t->cond);
     81 }
     82 
     83 static void rf_ShutdownMCPair(ignored)
     84   void  *ignored;
     85 {
     86 	RF_FREELIST_DESTROY_CLEAN(rf_mcpair_freelist,next,(RF_MCPair_t *),clean_mcpair);
     87 }
     88 
     89 int rf_ConfigureMCPair(listp)
     90   RF_ShutdownList_t  **listp;
     91 {
     92 	int rc;
     93 
     94 	RF_FREELIST_CREATE(rf_mcpair_freelist, RF_MAX_FREE_MCPAIR,
     95 		RF_MCPAIR_INC, sizeof(RF_MCPair_t));
     96 	rc = rf_ShutdownCreate(listp, rf_ShutdownMCPair, NULL);
     97 	if (rc) {
     98 		RF_ERRORMSG3("Unable to add to shutdown list file %s line %d rc=%d\n",
     99 			__FILE__, __LINE__, rc);
    100 		rf_ShutdownMCPair(NULL);
    101 		return(rc);
    102 	}
    103 	RF_FREELIST_PRIME_INIT(rf_mcpair_freelist, RF_MCPAIR_INITIAL,next,
    104 		(RF_MCPair_t *),init_mcpair);
    105 	return(0);
    106 }
    107 
    108 RF_MCPair_t *rf_AllocMCPair()
    109 {
    110 	RF_MCPair_t *t;
    111 
    112 	RF_FREELIST_GET_INIT(rf_mcpair_freelist,t,next,(RF_MCPair_t *),init_mcpair);
    113 	if (t) {
    114 		t->flag = 0;
    115 		t->next = NULL;
    116 	}
    117 	return(t);
    118 }
    119 
    120 void rf_FreeMCPair(t)
    121   RF_MCPair_t   *t;
    122 {
    123 	RF_FREELIST_FREE_CLEAN(rf_mcpair_freelist,t,next,clean_mcpair);
    124 }
    125 
    126 /* the callback function used to wake you up when you use an mcpair to wait for something */
    127 void rf_MCPairWakeupFunc(mcpair)
    128   RF_MCPair_t  *mcpair;
    129 {
    130 	RF_LOCK_MUTEX(mcpair->mutex);
    131 	mcpair->flag = 1;
    132 #if 0
    133 printf("MCPairWakeupFunc called!\n");
    134 #endif
    135 	wakeup(&(mcpair->flag)); /* XXX Does this do anything useful!! GO */
    136 	/* XXX Looks like the following is needed to truly get the
    137 functionality they were looking for here... This could be a side-effect
    138 of my using a tsleep in the NetBSD port though... XXX */
    139 	wakeup(&(mcpair->cond)); /* XXX XXX XXX GO */
    140 	RF_UNLOCK_MUTEX(mcpair->mutex);
    141 }
    142