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

The code seems to want to look at the last byte where the HW puts some
information. Since the skb->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 <bigeasy@linutronix.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index fefbf4d..37b7d1c 100644 (file)
--- 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,