1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
/*
* linux/drivers/acorn/scsi/msgqueue.c
*
* Copyright (C) 1997-1998 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* message queue handling
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include "msgqueue.h"
/*
* Function: struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
* Purpose : Allocate a message queue entry
* Params : msgq - message queue to claim entry for
* Returns : message queue entry or NULL.
*/
static struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq)
{
struct msgqueue_entry *mq;
if ((mq = msgq->free) != NULL)
msgq->free = mq->next;
return mq;
}
/*
* Function: void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
* Purpose : free a message queue entry
* Params : msgq - message queue to free entry from
* mq - message queue entry to free
*/
static void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq)
{
if (mq) {
mq->next = msgq->free;
msgq->free = mq;
}
}
/*
* Function: void msgqueue_initialise(MsgQueue_t *msgq)
* Purpose : initialise a message queue
* Params : msgq - queue to initialise
*/
void msgqueue_initialise(MsgQueue_t *msgq)
{
int i;
msgq->qe = NULL;
msgq->free = &msgq->entries[0];
for (i = 0; i < NR_MESSAGES; i++)
msgq->entries[i].next = &msgq->entries[i + 1];
msgq->entries[NR_MESSAGES - 1].next = NULL;
}
/*
* Function: void msgqueue_free(MsgQueue_t *msgq)
* Purpose : free a queue
* Params : msgq - queue to free
*/
void msgqueue_free(MsgQueue_t *msgq)
{
}
/*
* Function: int msgqueue_msglength(MsgQueue_t *msgq)
* Purpose : calculate the total length of all messages on the message queue
* Params : msgq - queue to examine
* Returns : number of bytes of messages in queue
*/
int msgqueue_msglength(MsgQueue_t *msgq)
{
struct msgqueue_entry *mq = msgq->qe;
int length = 0;
for (mq = msgq->qe; mq; mq = mq->next)
length += mq->msg.length;
return length;
}
/*
* Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
* Purpose : return a message
* Params : msgq - queue to obtain message from
* : msgno - message number
* Returns : pointer to message string, or NULL
*/
struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
{
struct msgqueue_entry *mq;
for (mq = msgq->qe; mq && msgno; mq = mq->next, msgno--);
return mq ? &mq->msg : NULL;
}
/*
* Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
* Purpose : add a message onto a message queue
* Params : msgq - queue to add message on
* length - length of message
* ... - message bytes
* Returns : != 0 if successful
*/
int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
{
struct msgqueue_entry *mq = mqe_alloc(msgq);
va_list ap;
if (mq) {
struct msgqueue_entry **mqp;
int i;
va_start(ap, length);
for (i = 0; i < length; i++)
mq->msg.msg[i] = va_arg(ap, unsigned int);
va_end(ap);
mq->msg.length = length;
mq->msg.fifo = 0;
mq->next = NULL;
mqp = &msgq->qe;
while (*mqp)
mqp = &(*mqp)->next;
*mqp = mq;
}
return mq != NULL;
}
/*
* Function: void msgqueue_flush(MsgQueue_t *msgq)
* Purpose : flush all messages from message queue
* Params : msgq - queue to flush
*/
void msgqueue_flush(MsgQueue_t *msgq)
{
struct msgqueue_entry *mq, *mqnext;
for (mq = msgq->qe; mq; mq = mqnext) {
mqnext = mq->next;
mqe_free(msgq, mq);
}
msgq->qe = NULL;
}
EXPORT_SYMBOL(msgqueue_initialise);
EXPORT_SYMBOL(msgqueue_free);
EXPORT_SYMBOL(msgqueue_msglength);
EXPORT_SYMBOL(msgqueue_getmsg);
EXPORT_SYMBOL(msgqueue_addmsg);
EXPORT_SYMBOL(msgqueue_flush);
MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("SCSI message queue handling");
MODULE_LICENSE("GPL");
|
