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@xxxxxxxxxxxxxxx>
---
drivers/nfc/pn533.c | 17 +++--------------
include/linux/nfc.h | 2 ++
include/net/nfc.h | 7 ++++++-
net/nfc/core.c | 6 +++++-
net/nfc/rawsock.c | 13 ++++++-------
5 files changed, 22 insertions(+), 23 deletions(-)
diff --git a/drivers/nfc/pn533.c b/drivers/nfc/pn533.c
index c77e054..f81a93e 100644
--- a/drivers/nfc/pn533.c
+++ b/drivers/nfc/pn533.c
@@ -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;
diff --git a/include/linux/nfc.h b/include/linux/nfc.h
index 330a4c5..c525e0b 100644
--- a/include/linux/nfc.h
+++ b/include/linux/nfc.h
@@ -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 */
diff --git a/include/net/nfc.h b/include/net/nfc.h
index cc01303..87b51fe 100644
--- a/include/net/nfc.h
+++ b/include/net/nfc.h
@@ -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
diff --git a/net/nfc/core.c b/net/nfc/core.c
index b6fd4e1..284e2f6 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -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);
diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c
index 52de84a..9fd652a 100644
--- a/net/nfc/rawsock.c
+++ b/net/nfc/rawsock.c
@@ -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);
--
1.7.5.3
--
Intel Open Source Technology Centre
http://oss.intel.com/
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