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Commit e8753043 authored by Samuel Ortiz's avatar Samuel Ortiz Committed by John W. Linville
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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: default avatarSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 4e0d8cc1

drivers/nfc/pn533.c

+3 −14
Original line number Diff line number Diff line
@@ -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;

include/linux/nfc.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

include/net/nfc.h

+6 −1
Original line number Diff line number Diff line
@@ -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

net/nfc/core.c

+5 −1
Original line number Diff line number Diff line
@@ -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);

net/nfc/rawsock.c

+6 −7
Original line number Diff line number Diff line
@@ -123,11 +123,7 @@ static int rawsock_connect(struct socket *sock, struct sockaddr *_addr, 


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);