sky2: fix VLAN receive processing (resend)

The length check for truncated frames was not correctly handling
the case where VLAN acceleration had already read the tag.
Also, the Yukon EX has some features that use high bit of status
as security tag.

Signed-off-by: Pierre-Yves Ritschard <pyr@spootnik.org>
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 5d812de..8b15654 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -2103,6 +2103,13 @@
  	struct sky2_port *sky2 = netdev_priv(dev);
 	struct rx_ring_info *re = sky2->rx_ring + sky2->rx_next;
 	struct sk_buff *skb = NULL;
+	u16 count = (status & GMR_FS_LEN) >> 16;
+
+#ifdef SKY2_VLAN_TAG_USED
+	/* Account for vlan tag */
+	if (sky2->vlgrp && (status & GMR_FS_VLAN))
+		count -= VLAN_HLEN;
+#endif
 
 	if (unlikely(netif_msg_rx_status(sky2)))
 		printk(KERN_DEBUG PFX "%s: rx slot %u status 0x%x len %d\n",
@@ -2117,7 +2124,8 @@
 	if (!(status & GMR_FS_RX_OK))
 		goto resubmit;
 
-	if (status >> 16 != length)
+	/* if length reported by DMA does not match PHY, packet was truncated */
+	if (length != count)
 		goto len_mismatch;
 
 	if (length < copybreak)
@@ -2133,6 +2141,10 @@
 	/* Truncation of overlength packets
 	   causes PHY length to not match MAC length */
 	++sky2->net_stats.rx_length_errors;
+	if (netif_msg_rx_err(sky2) && net_ratelimit())
+		pr_info(PFX "%s: rx length mismatch: length %d status %#x\n",
+			dev->name, length, status);
+	goto resubmit;
 
 error:
 	++sky2->net_stats.rx_errors;