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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
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17
drivers/nfc/pn533.c
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@@ -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;