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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/drivers/acorn/scsi/msgqueue.c4 *5 * Copyright (C) 1997-1998 Russell King6 *7 * message queue handling8 */9#include <linux/module.h>10#include <linux/kernel.h>11#include <linux/stddef.h>12#include <linux/init.h>13 14#include "msgqueue.h"15 16/*17 * Function: struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)18 * Purpose : Allocate a message queue entry19 * Params : msgq - message queue to claim entry for20 * Returns : message queue entry or NULL.21 */22static struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)23{24 struct msgqueue_entry *mq;25 26 if ((mq = msgq->free) != NULL)27 msgq->free = mq->next;28 29 return mq;30}31 32/*33 * Function: void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)34 * Purpose : free a message queue entry35 * Params : msgq - message queue to free entry from36 * mq - message queue entry to free37 */38static void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)39{40 if (mq) {41 mq->next = msgq->free;42 msgq->free = mq;43 }44}45 46/*47 * Function: void msgqueue_initialise(MsgQueue_t *msgq)48 * Purpose : initialise a message queue49 * Params : msgq - queue to initialise50 */51void msgqueue_initialise(MsgQueue_t *msgq)52{53 int i;54 55 msgq->qe = NULL;56 msgq->free = &msgq->entries[0];57 58 for (i = 0; i < NR_MESSAGES; i++)59 msgq->entries[i].next = &msgq->entries[i + 1];60 61 msgq->entries[NR_MESSAGES - 1].next = NULL;62}63 64 65/*66 * Function: void msgqueue_free(MsgQueue_t *msgq)67 * Purpose : free a queue68 * Params : msgq - queue to free69 */70void msgqueue_free(MsgQueue_t *msgq)71{72}73 74/*75 * Function: int msgqueue_msglength(MsgQueue_t *msgq)76 * Purpose : calculate the total length of all messages on the message queue77 * Params : msgq - queue to examine78 * Returns : number of bytes of messages in queue79 */80int msgqueue_msglength(MsgQueue_t *msgq)81{82 struct msgqueue_entry *mq = msgq->qe;83 int length = 0;84 85 for (mq = msgq->qe; mq; mq = mq->next)86 length += mq->msg.length;87 88 return length;89}90 91/*92 * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)93 * Purpose : return a message94 * Params : msgq - queue to obtain message from95 * : msgno - message number96 * Returns : pointer to message string, or NULL97 */98struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)99{100 struct msgqueue_entry *mq;101 102 for (mq = msgq->qe; mq && msgno; mq = mq->next, msgno--);103 104 return mq ? &mq->msg : NULL;105}106 107/*108 * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)109 * Purpose : add a message onto a message queue110 * Params : msgq - queue to add message on111 * length - length of message112 * ... - message bytes113 * Returns : != 0 if successful114 */115int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)116{117 struct msgqueue_entry *mq = mqe_alloc(msgq);118 va_list ap;119 120 if (mq) {121 struct msgqueue_entry **mqp;122 int i;123 124 va_start(ap, length);125 for (i = 0; i < length; i++)126 mq->msg.msg[i] = va_arg(ap, unsigned int);127 va_end(ap);128 129 mq->msg.length = length;130 mq->msg.fifo = 0;131 mq->next = NULL;132 133 mqp = &msgq->qe;134 while (*mqp)135 mqp = &(*mqp)->next;136 137 *mqp = mq;138 }139 140 return mq != NULL;141}142 143/*144 * Function: void msgqueue_flush(MsgQueue_t *msgq)145 * Purpose : flush all messages from message queue146 * Params : msgq - queue to flush147 */148void msgqueue_flush(MsgQueue_t *msgq)149{150 struct msgqueue_entry *mq, *mqnext;151 152 for (mq = msgq->qe; mq; mq = mqnext) {153 mqnext = mq->next;154 mqe_free(msgq, mq);155 }156 msgq->qe = NULL;157}158 159EXPORT_SYMBOL(msgqueue_initialise);160EXPORT_SYMBOL(msgqueue_free);161EXPORT_SYMBOL(msgqueue_msglength);162EXPORT_SYMBOL(msgqueue_getmsg);163EXPORT_SYMBOL(msgqueue_addmsg);164EXPORT_SYMBOL(msgqueue_flush);165 166MODULE_AUTHOR("Russell King");167MODULE_DESCRIPTION("SCSI message queue handling");168MODULE_LICENSE("GPL");169