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171 lines
3.8 KiB
171 lines
3.8 KiB
/*
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* linux/drivers/acorn/scsi/msgqueue.c
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*
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* Copyright (C) 1997-1998 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* message queue handling
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/stddef.h>
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#include <linux/init.h>
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#include "msgqueue.h"
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/*
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* Function: struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
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* Purpose : Allocate a message queue entry
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* Params : msgq - message queue to claim entry for
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* Returns : message queue entry or NULL.
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*/
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static struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
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{
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struct msgqueue_entry *mq;
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if ((mq = msgq->free) != NULL)
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msgq->free = mq->next;
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return mq;
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}
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/*
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* Function: void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
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* Purpose : free a message queue entry
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* Params : msgq - message queue to free entry from
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* mq - message queue entry to free
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*/
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static void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
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{
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if (mq) {
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mq->next = msgq->free;
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msgq->free = mq;
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}
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}
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/*
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* Function: void msgqueue_initialise(MsgQueue_t *msgq)
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* Purpose : initialise a message queue
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* Params : msgq - queue to initialise
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*/
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void msgqueue_initialise(MsgQueue_t *msgq)
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{
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int i;
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msgq->qe = NULL;
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msgq->free = &msgq->entries[0];
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for (i = 0; i < NR_MESSAGES; i++)
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msgq->entries[i].next = &msgq->entries[i + 1];
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msgq->entries[NR_MESSAGES - 1].next = NULL;
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}
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/*
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* Function: void msgqueue_free(MsgQueue_t *msgq)
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* Purpose : free a queue
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* Params : msgq - queue to free
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*/
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void msgqueue_free(MsgQueue_t *msgq)
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{
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}
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/*
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* Function: int msgqueue_msglength(MsgQueue_t *msgq)
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* Purpose : calculate the total length of all messages on the message queue
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* Params : msgq - queue to examine
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* Returns : number of bytes of messages in queue
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*/
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int msgqueue_msglength(MsgQueue_t *msgq)
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{
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struct msgqueue_entry *mq = msgq->qe;
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int length = 0;
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for (mq = msgq->qe; mq; mq = mq->next)
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length += mq->msg.length;
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return length;
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}
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/*
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* Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
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* Purpose : return a message
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* Params : msgq - queue to obtain message from
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* : msgno - message number
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* Returns : pointer to message string, or NULL
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*/
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struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
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{
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struct msgqueue_entry *mq;
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for (mq = msgq->qe; mq && msgno; mq = mq->next, msgno--);
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return mq ? &mq->msg : NULL;
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}
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/*
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* Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
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* Purpose : add a message onto a message queue
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* Params : msgq - queue to add message on
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* length - length of message
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* ... - message bytes
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* Returns : != 0 if successful
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*/
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int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
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{
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struct msgqueue_entry *mq = mqe_alloc(msgq);
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va_list ap;
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if (mq) {
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struct msgqueue_entry **mqp;
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int i;
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va_start(ap, length);
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for (i = 0; i < length; i++)
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mq->msg.msg[i] = va_arg(ap, unsigned int);
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va_end(ap);
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mq->msg.length = length;
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mq->msg.fifo = 0;
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mq->next = NULL;
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mqp = &msgq->qe;
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while (*mqp)
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mqp = &(*mqp)->next;
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*mqp = mq;
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}
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return mq != NULL;
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}
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/*
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* Function: void msgqueue_flush(MsgQueue_t *msgq)
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* Purpose : flush all messages from message queue
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* Params : msgq - queue to flush
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*/
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void msgqueue_flush(MsgQueue_t *msgq)
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{
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struct msgqueue_entry *mq, *mqnext;
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for (mq = msgq->qe; mq; mq = mqnext) {
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mqnext = mq->next;
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mqe_free(msgq, mq);
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}
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msgq->qe = NULL;
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}
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EXPORT_SYMBOL(msgqueue_initialise);
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EXPORT_SYMBOL(msgqueue_free);
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EXPORT_SYMBOL(msgqueue_msglength);
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EXPORT_SYMBOL(msgqueue_getmsg);
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EXPORT_SYMBOL(msgqueue_addmsg);
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EXPORT_SYMBOL(msgqueue_flush);
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MODULE_AUTHOR("Russell King");
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MODULE_DESCRIPTION("SCSI message queue handling");
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MODULE_LICENSE("GPL");
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