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/drivers/scsi/arm/msgqueue.h

http://github.com/mirrors/linux
C Header | 79 lines | 24 code | 11 blank | 44 comment | 0 complexity | 4bae2252b6fcdc72a665df336170afb8 MD5 | raw file
 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 *  linux/drivers/acorn/scsi/msgqueue.h
 4 *
 5 *  Copyright (C) 1997 Russell King
 6 *
 7 *  message queue handling
 8 */
 9#ifndef MSGQUEUE_H
10#define MSGQUEUE_H
11
12struct message {
13    char msg[8];
14    int length;
15    int fifo;
16};
17
18struct msgqueue_entry {
19    struct message msg;
20    struct msgqueue_entry *next;
21};
22
23#define NR_MESSAGES 4
24
25typedef struct {
26    struct msgqueue_entry *qe;
27    struct msgqueue_entry *free;
28    struct msgqueue_entry entries[NR_MESSAGES];
29} MsgQueue_t;
30
31/*
32 * Function: void msgqueue_initialise(MsgQueue_t *msgq)
33 * Purpose : initialise a message queue
34 * Params  : msgq - queue to initialise
35 */
36extern void msgqueue_initialise(MsgQueue_t *msgq);
37
38/*
39 * Function: void msgqueue_free(MsgQueue_t *msgq)
40 * Purpose : free a queue
41 * Params  : msgq - queue to free
42 */
43extern void msgqueue_free(MsgQueue_t *msgq);
44
45/*
46 * Function: int msgqueue_msglength(MsgQueue_t *msgq)
47 * Purpose : calculate the total length of all messages on the message queue
48 * Params  : msgq - queue to examine
49 * Returns : number of bytes of messages in queue
50 */
51extern int msgqueue_msglength(MsgQueue_t *msgq);
52
53/*
54 * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
55 * Purpose : return a message & its length
56 * Params  : msgq   - queue to obtain message from
57 *         : msgno  - message number
58 * Returns : pointer to message string, or NULL
59 */
60extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno);
61
62/*
63 * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
64 * Purpose : add a message onto a message queue
65 * Params  : msgq   - queue to add message on
66 *	     length - length of message
67 *	     ...    - message bytes
68 * Returns : != 0 if successful
69 */
70extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...);
71
72/*
73 * Function: void msgqueue_flush(MsgQueue_t *msgq)
74 * Purpose : flush all messages from message queue
75 * Params  : msgq - queue to flush
76 */
77extern void msgqueue_flush(MsgQueue_t *msgq);
78
79#endif