/* SPDX-License-Identifier: GPL-2.0-only */ /* * linux/drivers/acorn/scsi/msgqueue.h * * Copyright (C) 1997 Russell King * * message queue handling */ #ifndef MSGQUEUE_H #define MSGQUEUE_H struct message { char msg[8]; int length; int fifo; }; struct msgqueue_entry { struct message msg; struct msgqueue_entry *next; }; #define NR_MESSAGES 4 typedef struct { struct msgqueue_entry *qe; struct msgqueue_entry *free; struct msgqueue_entry entries[NR_MESSAGES]; } MsgQueue_t; /* * Function: void msgqueue_initialise(MsgQueue_t *msgq) * Purpose : initialise a message queue * Params : msgq - queue to initialise */ extern void msgqueue_initialise(MsgQueue_t *msgq); /* * Function: void msgqueue_free(MsgQueue_t *msgq) * Purpose : free a queue * Params : msgq - queue to free */ extern 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 */ extern int msgqueue_msglength(MsgQueue_t *msgq); /* * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) * Purpose : return a message & its length * Params : msgq - queue to obtain message from * : msgno - message number * Returns : pointer to message string, or NULL */ extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); /* * 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 */ extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); /* * Function: void msgqueue_flush(MsgQueue_t *msgq) * Purpose : flush all messages from message queue * Params : msgq - queue to flush */ extern void msgqueue_flush(MsgQueue_t *msgq); #endif