From e8753043f9fbabffbf087c7f4b514c50ef89541e Mon Sep 17 00:00:00 2001 From: Samuel Ortiz Date: Fri, 19 Aug 2011 15:47:11 +0200 Subject: [PATCH] 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 Signed-off-by: John W. Linville --- 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 c77e0543e502..f81a93e5b59d 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 330a4c5db588..c525e0b5876b 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 cc0130312f70..87b51fe15b70 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 b6fd4e1f2057..284e2f6a14ff 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 52de84a55115..9fd652a51424 100644 --- a/net/nfc/rawsock.c +++ b/net/nfc/rawsock.c @@ -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);