| 1 | |
| 2 | |
| 3 | * linux/drivers/acorn/scsi/msgqueue.c
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| 4 | *
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| 5 | * Copyright (C) 1997-1998 Russell King
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| 6 | *
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| 7 | * message queue handling
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| 8 |
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| 9 | #include <linux/module.h>
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| 10 | #include <linux/kernel.h>
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| 11 | #include <linux/stddef.h>
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| 12 | #include <linux/init.h>
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| 13 |
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| 14 | #include "msgqueue.h"
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| 15 |
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| 16 | |
| 17 | * Function: struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
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| 18 | * Purpose : Allocate a message queue entry
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| 19 | * Params : msgq - message queue to claim entry for
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| 20 | * Returns : message queue entry or NULL.
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| 21 |
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| 22 | static struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
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| 23 | {
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| 24 | struct msgqueue_entry *mq;
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| 25 |
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| 26 | if ((mq = msgq->free) != NULL)
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| 27 | msgq->free = mq->next;
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| 28 |
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| 29 | return mq;
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| 30 | }
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| 31 |
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| 32 | |
| 33 | * Function: void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
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| 34 | * Purpose : free a message queue entry
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| 35 | * Params : msgq - message queue to free entry from
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| 36 | * mq - message queue entry to free
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| 37 |
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| 38 | static void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
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| 39 | {
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| 40 | if (mq) {
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| 41 | mq->next = msgq->free;
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| 42 | msgq->free = mq;
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| 43 | }
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| 44 | }
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| 45 |
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| 46 | |
| 47 | * Function: void msgqueue_initialise(MsgQueue_t *msgq)
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| 48 | * Purpose : initialise a message queue
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| 49 | * Params : msgq - queue to initialise
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| 50 |
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| 51 | void msgqueue_initialise(MsgQueue_t *msgq)
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| 52 | {
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| 53 | int i;
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| 54 |
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| 55 | msgq->qe = NULL;
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| 56 | msgq->free = &msgq->entries[0];
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| 57 |
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| 58 | for (i = 0; i < NR_MESSAGES; i++)
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| 59 | msgq->entries[i].next = &msgq->entries[i + 1];
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| 60 |
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| 61 | msgq->entries[NR_MESSAGES - 1].next = NULL;
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| 62 | }
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| 63 |
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| 64 |
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| 65 | |
| 66 | * Function: void msgqueue_free(MsgQueue_t *msgq)
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| 67 | * Purpose : free a queue
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| 68 | * Params : msgq - queue to free
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| 69 |
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| 70 | void msgqueue_free(MsgQueue_t *msgq)
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| 71 | {
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| 72 | }
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| 73 |
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| 74 | |
| 75 | * Function: int msgqueue_msglength(MsgQueue_t *msgq)
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| 76 | * Purpose : calculate the total length of all messages on the message queue
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| 77 | * Params : msgq - queue to examine
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| 78 | * Returns : number of bytes of messages in queue
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| 79 |
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| 80 | int msgqueue_msglength(MsgQueue_t *msgq)
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| 81 | {
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| 82 | struct msgqueue_entry *mq = msgq->qe;
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| 83 | int length = 0;
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| 84 |
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| 85 | for (mq = msgq->qe; mq; mq = mq->next)
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| 86 | length += mq->msg.length;
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| 87 |
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| 88 | return length;
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| 89 | }
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| 90 |
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| 91 | |
| 92 | * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
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| 93 | * Purpose : return a message
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| 94 | * Params : msgq - queue to obtain message from
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| 95 | * : msgno - message number
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| 96 | * Returns : pointer to message string, or NULL
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| 97 |
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| 98 | struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
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| 99 | {
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| 100 | struct msgqueue_entry *mq;
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| 101 |
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| 102 | for (mq = msgq->qe; mq && msgno; mq = mq->next, msgno--);
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| 103 |
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| 104 | return mq ? &mq->msg : NULL;
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| 105 | }
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| 106 |
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| 107 | |
| 108 | * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
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| 109 | * Purpose : add a message onto a message queue
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| 110 | * Params : msgq - queue to add message on
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| 111 | * length - length of message
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| 112 | * ... - message bytes
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| 113 | * Returns : != 0 if successful
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| 114 |
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| 115 | int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
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| 116 | {
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| 117 | struct msgqueue_entry *mq = mqe_alloc(msgq);
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| 118 | va_list ap;
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| 119 |
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| 120 | if (mq) {
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| 121 | struct msgqueue_entry **mqp;
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| 122 | int i;
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| 123 |
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| 124 | va_start(ap, length);
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| 125 | for (i = 0; i < length; i++)
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| 126 | mq->msg.msg[i] = va_arg(ap, unsigned int);
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| 127 | va_end(ap);
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| 128 |
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| 129 | mq->msg.length = length;
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| 130 | mq->msg.fifo = 0;
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| 131 | mq->next = NULL;
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| 132 |
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| 133 | mqp = &msgq->qe;
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| 134 | while (*mqp)
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| 135 | mqp = &(*mqp)->next;
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| 136 |
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| 137 | *mqp = mq;
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| 138 | }
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| 139 |
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| 140 | return mq != NULL;
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| 141 | }
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| 142 |
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| 143 | |
| 144 | * Function: void msgqueue_flush(MsgQueue_t *msgq)
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| 145 | * Purpose : flush all messages from message queue
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| 146 | * Params : msgq - queue to flush
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| 147 |
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| 148 | void msgqueue_flush(MsgQueue_t *msgq)
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| 149 | {
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| 150 | struct msgqueue_entry *mq, *mqnext;
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| 151 |
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| 152 | for (mq = msgq->qe; mq; mq = mqnext) {
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| 153 | mqnext = mq->next;
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| 154 | mqe_free(msgq, mq);
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| 155 | }
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| 156 | msgq->qe = NULL;
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| 157 | }
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| 158 |
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| 159 | EXPORT_SYMBOL(msgqueue_initialise);
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| 160 | EXPORT_SYMBOL(msgqueue_free);
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| 161 | EXPORT_SYMBOL(msgqueue_msglength);
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| 162 | EXPORT_SYMBOL(msgqueue_getmsg);
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| 163 | EXPORT_SYMBOL(msgqueue_addmsg);
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| 164 | EXPORT_SYMBOL(msgqueue_flush);
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| 165 |
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| 166 | MODULE_AUTHOR("Russell King");
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| 167 | MODULE_DESCRIPTION("SCSI message queue handling");
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| 168 | MODULE_LICENSE("GPL");
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