buffer_info->skb = skb;
                buffer_info->length = (u16) adapter->rx_buffer_len;
                page = virt_to_page(skb->data);
-               offset = (unsigned long)skb->data & ~PAGE_MASK;
+               offset = offset_in_page(skb->data);
                buffer_info->dma = pci_map_page(pdev, page, offset,
                                                adapter->rx_buffer_len,
                                                PCI_DMA_FROMDEVICE);
                hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
                buffer_info->length = hdr_len;
                page = virt_to_page(skb->data);
-               offset = (unsigned long)skb->data & ~PAGE_MASK;
+               offset = offset_in_page(skb->data);
                buffer_info->dma = pci_map_page(adapter->pdev, page,
                                                offset, hdr_len,
                                                PCI_DMA_TODEVICE);
                                data_len -= buffer_info->length;
                                page = virt_to_page(skb->data +
                                        (hdr_len + i * ATL1_MAX_TX_BUF_LEN));
-                               offset = (unsigned long)(skb->data +
-                                       (hdr_len + i * ATL1_MAX_TX_BUF_LEN)) &
-                                       ~PAGE_MASK;
+                               offset = offset_in_page(skb->data +
+                                       (hdr_len + i * ATL1_MAX_TX_BUF_LEN));
                                buffer_info->dma = pci_map_page(adapter->pdev,
                                        page, offset, buffer_info->length,
                                        PCI_DMA_TODEVICE);
                /* not TSO */
                buffer_info->length = buf_len;
                page = virt_to_page(skb->data);
-               offset = (unsigned long)skb->data & ~PAGE_MASK;
+               offset = offset_in_page(skb->data);
                buffer_info->dma = pci_map_page(adapter->pdev, page,
                        offset, buf_len, PCI_DMA_TODEVICE);
                if (++next_to_use == tpd_ring->count)