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 <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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 @@
{
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 @@
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 @@
| 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;