LXR linux/drivers/scsi/arm/msgqueue.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/drivers/acorn/scsi/msgqueue.c
   4 *
   5 *  Copyright (C) 1997-1998 Russell King
   6 *
   7 *  message queue handling
   8 */
   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 entry
  19 * Params  : msgq - message queue to claim entry for
  20 * 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 entry
  35 * Params  : msgq - message queue to free entry from
  36 *           mq   - message queue entry to free
  37 */
  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 queue
  49 * Params  : msgq - queue to initialise
  50 */
  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 queue
  68 * Params  : msgq - queue to free
  69 */
  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 queue
  77 * Params  : msgq - queue to examine
  78 * Returns : number of bytes of messages in queue
  79 */
  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 message
  94 * Params  : msgq   - queue to obtain message from
  95 *         : msgno  - message number
  96 * Returns : pointer to message string, or NULL
  97 */
  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 queue
 110 * Params  : msgq   - queue to add message on
 111 *           length - length of message
 112 *           ...    - message bytes
 113 * Returns : != 0 if successful
 114 */
 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 queue
 146 * Params  : msgq - queue to flush
 147 */
 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