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linux-next/net/nfc/af_nfc.c
linzhang 173e7837a2 net: socket: mark socket protocol handler structs as const
Signed-off-by: linzhang <xiaolou4617@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-16 11:54:07 -04:00

98 lines
2.4 KiB
C

/*
* Copyright (C) 2011 Instituto Nokia de Tecnologia
*
* Authors:
* Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
* Lauro Ramos Venancio <lauro.venancio@openbossa.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/nfc.h>
#include <linux/module.h>
#include "nfc.h"
static DEFINE_RWLOCK(proto_tab_lock);
static const struct nfc_protocol *proto_tab[NFC_SOCKPROTO_MAX];
static int nfc_sock_create(struct net *net, struct socket *sock, int proto,
int kern)
{
int rc = -EPROTONOSUPPORT;
if (net != &init_net)
return -EAFNOSUPPORT;
if (proto < 0 || proto >= NFC_SOCKPROTO_MAX)
return -EINVAL;
read_lock(&proto_tab_lock);
if (proto_tab[proto] && try_module_get(proto_tab[proto]->owner)) {
rc = proto_tab[proto]->create(net, sock, proto_tab[proto], kern);
module_put(proto_tab[proto]->owner);
}
read_unlock(&proto_tab_lock);
return rc;
}
static const struct net_proto_family nfc_sock_family_ops = {
.owner = THIS_MODULE,
.family = PF_NFC,
.create = nfc_sock_create,
};
int nfc_proto_register(const struct nfc_protocol *nfc_proto)
{
int rc;
if (nfc_proto->id < 0 || nfc_proto->id >= NFC_SOCKPROTO_MAX)
return -EINVAL;
rc = proto_register(nfc_proto->proto, 0);
if (rc)
return rc;
write_lock(&proto_tab_lock);
if (proto_tab[nfc_proto->id])
rc = -EBUSY;
else
proto_tab[nfc_proto->id] = nfc_proto;
write_unlock(&proto_tab_lock);
return rc;
}
EXPORT_SYMBOL(nfc_proto_register);
void nfc_proto_unregister(const struct nfc_protocol *nfc_proto)
{
write_lock(&proto_tab_lock);
proto_tab[nfc_proto->id] = NULL;
write_unlock(&proto_tab_lock);
proto_unregister(nfc_proto->proto);
}
EXPORT_SYMBOL(nfc_proto_unregister);
int __init af_nfc_init(void)
{
return sock_register(&nfc_sock_family_ops);
}
void af_nfc_exit(void)
{
sock_unregister(PF_NFC);
}