[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/net/tulip/xircom_tulip_cb.c b/drivers/net/tulip/xircom_tulip_cb.c
index 3f24c82..696b3b8 100644
--- a/drivers/net/tulip/xircom_tulip_cb.c
+++ b/drivers/net/tulip/xircom_tulip_cb.c
@@ -915,7 +915,9 @@
 
 	tp->tx_skbuff[entry] = skb;
 	if (tp->chip_id == X3201_3) {
-		memcpy(tp->tx_aligned_skbuff[entry]->data,skb->data,skb->len);
+		skb_copy_from_linear_data(skb,
+					  tp->tx_aligned_skbuff[entry]->data,
+					  skb->len);
 		tp->tx_ring[entry].buffer1 = virt_to_bus(tp->tx_aligned_skbuff[entry]->data);
 	} else
 		tp->tx_ring[entry].buffer1 = virt_to_bus(skb->data);