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>

2 files changed, 14 insertions, 2 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 5d812de65d90..8b1565453f08 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -2103,6 +2103,13 @@ static struct sk_buff *sky2_receive(struct net_device *dev,
         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 @@ static struct sk_buff *sky2_receive(struct net_device *dev,
         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 @@ len_mismatch:
         /* 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;
diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index 72e12b7cfa40..3baae48f8042 100644
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -1668,7 +1668,7 @@ enum {
 
 /* Receive Frame Status Encoding */
 enum {
-        GMR_FS_LEN      = 0xffff<<16, /* Bit 31..16:    Rx Frame Length */
+        GMR_FS_LEN      = 0x7fff<<16, /* Bit 30..16:    Rx Frame Length */
         GMR_FS_VLAN     = 1<<13, /* VLAN Packet */
         GMR_FS_JABBER   = 1<<12, /* Jabber Packet */
         GMR_FS_UN_SIZE  = 1<<11, /* Undersize Packet */