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NFC: Reserve tx head and tail room

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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>
This commit is contained in:
Samuel Ortiz 2011-08-19 15:47:11 +02:00 committed by John W. Linville
parent 4e0d8cc100
commit e8753043f9
5 changed files with 22 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
drivers/nfc/pn533.c
View file

@ -1246,7 +1246,6 @@ static int pn533_data_exchange_tx_frame(struct pn533 *dev, struct sk_buff *skb)
{
int payload_len = skb->len;
struct pn533_frame *out_frame;
struct sk_buff *discarded;
u8 tg;
nfc_dev_dbg(&dev->interface->dev, "%s - Sending %d bytes", __func__,
@ -1260,18 +1259,6 @@ static int pn533_data_exchange_tx_frame(struct pn533 *dev, struct sk_buff *skb)
return -ENOSYS;
}
/* Reserving header space */
if (skb_cow_head(skb, PN533_CMD_DATAEXCH_HEAD_LEN)) {
nfc_dev_err(&dev->interface->dev, "Error to add header data");
return -ENOMEM;
}
/* Reserving tail space, see pn533_tx_frame_finish */
if (skb_cow_data(skb, PN533_FRAME_TAIL_SIZE, &discarded) < 0) {
nfc_dev_err(&dev->interface->dev, "Error to add tail data");
return -ENOMEM;
}
skb_push(skb, PN533_CMD_DATAEXCH_HEAD_LEN);
out_frame = (struct pn533_frame *) skb->data;
@ -1536,7 +1523,9 @@ static int pn533_probe(struct usb_interface *interface,
| NFC_PROTO_ISO14443_MASK
| NFC_PROTO_NFC_DEP_MASK;
dev->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols);
dev->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
PN533_CMD_DATAEXCH_HEAD_LEN,
PN533_FRAME_TAIL_SIZE);
if (!dev->nfc_dev)
goto kill_tasklet;

2
include/linux/nfc.h
View file

@ -123,4 +123,6 @@ struct sockaddr_nfc {
#define NFC_SOCKPROTO_RAW 0
#define NFC_SOCKPROTO_MAX 1
#define NFC_HEADER_SIZE 1
#endif /*__LINUX_NFC_H */

7
include/net/nfc.h
View file

@ -82,6 +82,9 @@ struct nfc_dev {
struct nfc_genl_data genl_data;
u32 supported_protocols;
int tx_headroom;
int tx_tailroom;
struct nfc_ops *ops;
};
#define to_nfc_dev(_dev) container_of(_dev, struct nfc_dev, dev)
@ -89,7 +92,9 @@ struct nfc_dev {
extern struct class nfc_class;
struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
u32 supported_protocols);
u32 supported_protocols,
int tx_headroom,
int tx_tailroom);
/**
* nfc_free_device - free nfc device

6
net/nfc/core.c
View file

@ -322,7 +322,9 @@ struct nfc_dev *nfc_get_device(unsigned idx)
* @supported_protocols: NFC protocols supported by the device
*/
struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
u32 supported_protocols)
u32 supported_protocols,
int tx_headroom,
int tx_tailroom)
{
static atomic_t dev_no = ATOMIC_INIT(0);
struct nfc_dev *dev;
@ -345,6 +347,8 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
dev->ops = ops;
dev->supported_protocols = supported_protocols;
dev->tx_headroom = tx_headroom;
dev->tx_tailroom = tx_tailroom;
spin_lock_init(&dev->targets_lock);
nfc_genl_data_init(&dev->genl_data);

13
net/nfc/rawsock.c
View file

@ -123,11 +123,7 @@ error:
static int rawsock_add_header(struct sk_buff *skb)
{
if (skb_cow_head(skb, 1))
return -ENOMEM;
*skb_push(skb, 1) = 0;
*skb_push(skb, NFC_HEADER_SIZE) = 0;
return 0;
}
@ -197,6 +193,7 @@ 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;
@ -208,11 +205,13 @@ static int rawsock_sendmsg(struct kiocb *iocb, struct socket *sock,
if (sock->state != SS_CONNECTED)
return -ENOTCONN;
skb = sock_alloc_send_skb(sk, len, msg->msg_flags & MSG_DONTWAIT,
&rc);
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);