linux/net/nfc/rawsock.c
Samuel Ortiz e8753043f9 NFC: Reserve tx head and tail room
We can have the NFC core layer allocating the tx head and tail
room for the drivers and avoid 1 or more SKBs copy on write on
the Tx path.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-08-24 14:41:44 -04:00

354 lines
7.7 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, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <net/tcp_states.h>
#include <linux/nfc.h>
#include "nfc.h"
static void rawsock_write_queue_purge(struct sock *sk)
{
nfc_dbg("sk=%p", sk);
spin_lock_bh(&sk->sk_write_queue.lock);
__skb_queue_purge(&sk->sk_write_queue);
nfc_rawsock(sk)->tx_work_scheduled = false;
spin_unlock_bh(&sk->sk_write_queue.lock);
}
static void rawsock_report_error(struct sock *sk, int err)
{
nfc_dbg("sk=%p err=%d", sk, err);
sk->sk_shutdown = SHUTDOWN_MASK;
sk->sk_err = -err;
sk->sk_error_report(sk);
rawsock_write_queue_purge(sk);
}
static int rawsock_release(struct socket *sock)
{
struct sock *sk = sock->sk;
nfc_dbg("sock=%p", sock);
sock_orphan(sk);
sock_put(sk);
return 0;
}
static int rawsock_connect(struct socket *sock, struct sockaddr *_addr,
int len, int flags)
{
struct sock *sk = sock->sk;
struct sockaddr_nfc *addr = (struct sockaddr_nfc *)_addr;
struct nfc_dev *dev;
int rc = 0;
nfc_dbg("sock=%p sk=%p flags=%d", sock, sk, flags);
if (!addr || len < sizeof(struct sockaddr_nfc) ||
addr->sa_family != AF_NFC)
return -EINVAL;
nfc_dbg("addr dev_idx=%u target_idx=%u protocol=%u", addr->dev_idx,
addr->target_idx, addr->nfc_protocol);
lock_sock(sk);
if (sock->state == SS_CONNECTED) {
rc = -EISCONN;
goto error;
}
dev = nfc_get_device(addr->dev_idx);
if (!dev) {
rc = -ENODEV;
goto error;
}
if (addr->target_idx > dev->target_idx - 1 ||
addr->target_idx < dev->target_idx - dev->n_targets) {
rc = -EINVAL;
goto error;
}
if (addr->target_idx > dev->target_idx - 1 ||
addr->target_idx < dev->target_idx - dev->n_targets) {
rc = -EINVAL;
goto error;
}
rc = nfc_activate_target(dev, addr->target_idx, addr->nfc_protocol);
if (rc)
goto put_dev;
nfc_rawsock(sk)->dev = dev;
nfc_rawsock(sk)->target_idx = addr->target_idx;
sock->state = SS_CONNECTED;
sk->sk_state = TCP_ESTABLISHED;
sk->sk_state_change(sk);
release_sock(sk);
return 0;
put_dev:
nfc_put_device(dev);
error:
release_sock(sk);
return rc;
}
static int rawsock_add_header(struct sk_buff *skb)
{
*skb_push(skb, NFC_HEADER_SIZE) = 0;
return 0;
}
static void rawsock_data_exchange_complete(void *context, struct sk_buff *skb,
int err)
{
struct sock *sk = (struct sock *) context;
BUG_ON(in_irq());
nfc_dbg("sk=%p err=%d", sk, err);
if (err)
goto error;
err = rawsock_add_header(skb);
if (err)
goto error;
err = sock_queue_rcv_skb(sk, skb);
if (err)
goto error;
spin_lock_bh(&sk->sk_write_queue.lock);
if (!skb_queue_empty(&sk->sk_write_queue))
schedule_work(&nfc_rawsock(sk)->tx_work);
else
nfc_rawsock(sk)->tx_work_scheduled = false;
spin_unlock_bh(&sk->sk_write_queue.lock);
sock_put(sk);
return;
error:
rawsock_report_error(sk, err);
sock_put(sk);
}
static void rawsock_tx_work(struct work_struct *work)
{
struct sock *sk = to_rawsock_sk(work);
struct nfc_dev *dev = nfc_rawsock(sk)->dev;
u32 target_idx = nfc_rawsock(sk)->target_idx;
struct sk_buff *skb;
int rc;
nfc_dbg("sk=%p target_idx=%u", sk, target_idx);
if (sk->sk_shutdown & SEND_SHUTDOWN) {
rawsock_write_queue_purge(sk);
return;
}
skb = skb_dequeue(&sk->sk_write_queue);
sock_hold(sk);
rc = nfc_data_exchange(dev, target_idx, skb,
rawsock_data_exchange_complete, sk);
if (rc) {
rawsock_report_error(sk, rc);
sock_put(sk);
}
}
static int rawsock_sendmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct nfc_dev *dev = nfc_rawsock(sk)->dev;
struct sk_buff *skb;
int rc;
nfc_dbg("sock=%p sk=%p len=%zu", sock, sk, len);
if (msg->msg_namelen)
return -EOPNOTSUPP;
if (sock->state != SS_CONNECTED)
return -ENOTCONN;
skb = sock_alloc_send_skb(sk, len + dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE,
msg->msg_flags & MSG_DONTWAIT, &rc);
if (!skb)
return rc;
skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
if (rc < 0) {
kfree_skb(skb);
return rc;
}
spin_lock_bh(&sk->sk_write_queue.lock);
__skb_queue_tail(&sk->sk_write_queue, skb);
if (!nfc_rawsock(sk)->tx_work_scheduled) {
schedule_work(&nfc_rawsock(sk)->tx_work);
nfc_rawsock(sk)->tx_work_scheduled = true;
}
spin_unlock_bh(&sk->sk_write_queue.lock);
return len;
}
static int rawsock_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t len, int flags)
{
int noblock = flags & MSG_DONTWAIT;
struct sock *sk = sock->sk;
struct sk_buff *skb;
int copied;
int rc;
nfc_dbg("sock=%p sk=%p len=%zu flags=%d", sock, sk, len, flags);
skb = skb_recv_datagram(sk, flags, noblock, &rc);
if (!skb)
return rc;
msg->msg_namelen = 0;
copied = skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;
copied = len;
}
rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
skb_free_datagram(sk, skb);
return rc ? : copied;
}
static const struct proto_ops rawsock_ops = {
.family = PF_NFC,
.owner = THIS_MODULE,
.release = rawsock_release,
.bind = sock_no_bind,
.connect = rawsock_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = datagram_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = rawsock_sendmsg,
.recvmsg = rawsock_recvmsg,
.mmap = sock_no_mmap,
};
static void rawsock_destruct(struct sock *sk)
{
nfc_dbg("sk=%p", sk);
if (sk->sk_state == TCP_ESTABLISHED) {
nfc_deactivate_target(nfc_rawsock(sk)->dev,
nfc_rawsock(sk)->target_idx);
nfc_put_device(nfc_rawsock(sk)->dev);
}
skb_queue_purge(&sk->sk_receive_queue);
if (!sock_flag(sk, SOCK_DEAD)) {
nfc_err("Freeing alive NFC raw socket %p", sk);
return;
}
}
static int rawsock_create(struct net *net, struct socket *sock,
const struct nfc_protocol *nfc_proto)
{
struct sock *sk;
nfc_dbg("sock=%p", sock);
if (sock->type != SOCK_SEQPACKET)
return -ESOCKTNOSUPPORT;
sock->ops = &rawsock_ops;
sk = sk_alloc(net, PF_NFC, GFP_KERNEL, nfc_proto->proto);
if (!sk)
return -ENOMEM;
sock_init_data(sock, sk);
sk->sk_protocol = nfc_proto->id;
sk->sk_destruct = rawsock_destruct;
sock->state = SS_UNCONNECTED;
INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);
nfc_rawsock(sk)->tx_work_scheduled = false;
return 0;
}
static struct proto rawsock_proto = {
.name = "NFC_RAW",
.owner = THIS_MODULE,
.obj_size = sizeof(struct nfc_rawsock),
};
static const struct nfc_protocol rawsock_nfc_proto = {
.id = NFC_SOCKPROTO_RAW,
.proto = &rawsock_proto,
.owner = THIS_MODULE,
.create = rawsock_create
};
int __init rawsock_init(void)
{
int rc;
rc = nfc_proto_register(&rawsock_nfc_proto);
return rc;
}
void rawsock_exit(void)
{
nfc_proto_unregister(&rawsock_nfc_proto);
}