Home | History | Annotate | Line # | Download | only in raidframe
rf_mcpair.c revision 1.3 
      1 /*	$NetBSD: rf_mcpair.c,v 1.3 1999/02/05 00:06:13 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
     56 init_mcpair(t)
     57 	RF_MCPair_t *t;
     58 {
     59 	int     rc;
     60 
     61 	rc = rf_mutex_init(&t->mutex);
     62 	if (rc) {
     63 		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
     64 		    __LINE__, rc);
     65 		return (rc);
     66 	}
     67 	rc = rf_cond_init(&t->cond);
     68 	if (rc) {
     69 		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", __FILE__,
     70 		    __LINE__, rc);
     71 		rf_mutex_destroy(&t->mutex);
     72 		return (rc);
     73 	}
     74 	return (0);
     75 }
     76 
     77 static void
     78 clean_mcpair(t)
     79 	RF_MCPair_t *t;
     80 {
     81 	rf_mutex_destroy(&t->mutex);
     82 	rf_cond_destroy(&t->cond);
     83 }
     84 
     85 static void
     86 rf_ShutdownMCPair(ignored)
     87 	void   *ignored;
     88 {
     89 	RF_FREELIST_DESTROY_CLEAN(rf_mcpair_freelist, next, (RF_MCPair_t *), clean_mcpair);
     90 }
     91 
     92 int
     93 rf_ConfigureMCPair(listp)
     94 	RF_ShutdownList_t **listp;
     95 {
     96 	int     rc;
     97 
     98 	RF_FREELIST_CREATE(rf_mcpair_freelist, RF_MAX_FREE_MCPAIR,
     99 	    RF_MCPAIR_INC, sizeof(RF_MCPair_t));
    100 	rc = rf_ShutdownCreate(listp, rf_ShutdownMCPair, NULL);
    101 	if (rc) {
    102 		RF_ERRORMSG3("Unable to add to shutdown list file %s line %d rc=%d\n",
    103 		    __FILE__, __LINE__, rc);
    104 		rf_ShutdownMCPair(NULL);
    105 		return (rc);
    106 	}
    107 	RF_FREELIST_PRIME_INIT(rf_mcpair_freelist, RF_MCPAIR_INITIAL, next,
    108 	    (RF_MCPair_t *), init_mcpair);
    109 	return (0);
    110 }
    111 
    112 RF_MCPair_t *
    113 rf_AllocMCPair()
    114 {
    115 	RF_MCPair_t *t;
    116 
    117 	RF_FREELIST_GET_INIT(rf_mcpair_freelist, t, next, (RF_MCPair_t *), init_mcpair);
    118 	if (t) {
    119 		t->flag = 0;
    120 		t->next = NULL;
    121 	}
    122 	return (t);
    123 }
    124 
    125 void
    126 rf_FreeMCPair(t)
    127 	RF_MCPair_t *t;
    128 {
    129 	RF_FREELIST_FREE_CLEAN(rf_mcpair_freelist, t, next, clean_mcpair);
    130 }
    131 /* the callback function used to wake you up when you use an mcpair to wait for something */
    132 void
    133 rf_MCPairWakeupFunc(mcpair)
    134 	RF_MCPair_t *mcpair;
    135 {
    136 	RF_LOCK_MUTEX(mcpair->mutex);
    137 	mcpair->flag = 1;
    138 #if 0
    139 	printf("MCPairWakeupFunc called!\n");
    140 #endif
    141 	wakeup(&(mcpair->flag));/* XXX Does this do anything useful!! GO */
    142 	/* XXX Looks like the following is needed to truly get the
    143 	 * functionality they were looking for here... This could be a
    144 	 * side-effect of my using a tsleep in the NetBSD port though... XXX */
    145 	wakeup(&(mcpair->cond));/* XXX XXX XXX GO */
    146 	RF_UNLOCK_MUTEX(mcpair->mutex);
    147 }
    148