e1000: look in the page and not in skb->data for the last byte

Sebastian Andrzej Siewior · Jeff Kirsher · commit a3060858c207 · 2012-05-17T05:03:12.000-07:00
The code seems to want to look at the last byte where the HW puts some
information. Since the skb-&gt;data area is never seen by the HW I guess it
does not work as expected. We pass the page address to the HW so I
*think* in order to get to the last byte where the information might be
one should use the page buffer and take a look.
This is of course not more than just compile tested.

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Tested-by: Aaron Brown &lt;aaron.f.brown@intel.com&gt;
Signed-off-by: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -4066,7 +4066,11 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
 		/* errors is only valid for DD + EOP descriptors */
 		if (unlikely((status & E1000_RXD_STAT_EOP) &&
 		    (rx_desc->errors & E1000_RXD_ERR_FRAME_ERR_MASK))) {
-			u8 last_byte = *(skb->data + length - 1);
+			u8 *mapped;
+			u8 last_byte;
+
+			mapped = page_address(buffer_info->page);
+			last_byte = *(mapped + length - 1);
 			if (TBI_ACCEPT(hw, status, rx_desc->errors, length,
 				       last_byte)) {
 				spin_lock_irqsave(&adapter->stats_lock,
