[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/b44.c b/drivers/net/b44.c
index f67d97d..879a2ff 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -828,8 +828,8 @@
 			skb_reserve(copy_skb, 2);
 			skb_put(copy_skb, len);
 			/* DMA sync done above, copy just the actual packet */
-			memcpy(copy_skb->data, skb->data+bp->rx_offset, len);
-
+			skb_copy_from_linear_data_offset(skb, bp->rx_offset,
+							 copy_skb->data, len);
 			skb = copy_skb;
 		}
 		skb->ip_summed = CHECKSUM_NONE;
@@ -1006,7 +1006,8 @@
 			goto err_out;
 		}
 
-		memcpy(skb_put(bounce_skb, len), skb->data, skb->len);
+		skb_copy_from_linear_data(skb, skb_put(bounce_skb, len),
+					  skb->len);
 		dev_kfree_skb_any(skb);
 		skb = bounce_skb;
 	}