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// SPDX-License-Identifier: GPL-2.0
/*
* DIBS - Direct Internal Buffer Sharing
*
* Implementation of the DIBS class module
*
* Copyright IBM Corp. 2025
*/
#define KMSG_COMPONENT "dibs"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/dibs.h>
MODULE_DESCRIPTION("Direct Internal Buffer Sharing class");
MODULE_LICENSE("GPL");
/* use an array rather a list for fast mapping: */
static struct dibs_client *clients[MAX_DIBS_CLIENTS];
static u8 max_client;
static DEFINE_MUTEX(clients_lock);
int dibs_register_client(struct dibs_client *client)
{
int i, rc = -ENOSPC;
mutex_lock(&clients_lock);
for (i = 0; i < MAX_DIBS_CLIENTS; ++i) {
if (!clients[i]) {
clients[i] = client;
client->id = i;
if (i == max_client)
max_client++;
rc = 0;
break;
}
}
mutex_unlock(&clients_lock);
return rc;
}
EXPORT_SYMBOL_GPL(dibs_register_client);
int dibs_unregister_client(struct dibs_client *client)
{
int rc = 0;
mutex_lock(&clients_lock);
clients[client->id] = NULL;
if (client->id + 1 == max_client)
max_client--;
mutex_unlock(&clients_lock);
return rc;
}
EXPORT_SYMBOL_GPL(dibs_unregister_client);
static int __init dibs_init(void)
{
memset(clients, 0, sizeof(clients));
max_client = 0;
return 0;
}
static void __exit dibs_exit(void)
{
}
module_init(dibs_init);
module_exit(dibs_exit);
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