[SK_BUFF]: Introduce skb_copy_from_linear_data{_offset}

To clearly state the intent of copying from linear sk_buffs, _offset being a
overly long variant but interesting for the sake of saving some bytes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index a076f73..d287c57 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -484,7 +484,7 @@
 		ptr[4] = 0xec;
 		ptr += ATM_CELL_HEADER;
 
-		memcpy(ptr, skb->data, data_len);
+		skb_copy_from_linear_data(skb, ptr, data_len);
 		ptr += data_len;
 		__skb_pull(skb, data_len);
 
diff --git a/drivers/usb/net/catc.c b/drivers/usb/net/catc.c
index d82022d..ffec2e0 100644
--- a/drivers/usb/net/catc.c
+++ b/drivers/usb/net/catc.c
@@ -418,7 +418,7 @@
 	catc->tx_ptr = (((catc->tx_ptr - 1) >> 6) + 1) << 6;
 	tx_buf = catc->tx_buf[catc->tx_idx] + catc->tx_ptr;
 	*((u16*)tx_buf) = (catc->is_f5u011) ? cpu_to_be16((u16)skb->len) : cpu_to_le16((u16)skb->len);
-	memcpy(tx_buf + 2, skb->data, skb->len);
+	skb_copy_from_linear_data(skb, tx_buf + 2, skb->len);
 	catc->tx_ptr += skb->len + 2;
 
 	if (!test_and_set_bit(TX_RUNNING, &catc->flags))
diff --git a/drivers/usb/net/pegasus.c b/drivers/usb/net/pegasus.c
index 13f70e0..1ad4ee5 100644
--- a/drivers/usb/net/pegasus.c
+++ b/drivers/usb/net/pegasus.c
@@ -889,7 +889,7 @@
 	netif_stop_queue(net);
 
 	((__le16 *) pegasus->tx_buff)[0] = cpu_to_le16(l16);
-	memcpy(pegasus->tx_buff + 2, skb->data, skb->len);
+	skb_copy_from_linear_data(skb, pegasus->tx_buff + 2, skb->len);
 	usb_fill_bulk_urb(pegasus->tx_urb, pegasus->usb,
 			  usb_sndbulkpipe(pegasus->usb, 2),
 			  pegasus->tx_buff, count,