ixgbe: Do not pad FCoE frames as this can cause issues with FCoE DDP

FCoE target mode was experiencing issues due to the fact that we were
sending up data frames that were padded to 60 bytes after the DDP logic had
already stripped the frame down to 52 or 56 depending on the use of VLANs.
This was resulting in the FCoE DDP logic having issues since it thought the
frame still had data in it due to the padding.

To resolve this, adding code so that we do not pad FCoE frames prior to
handling them to the stack.

CC: <stable@vger.kernel.org>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index 3ef3c52..7af291e 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -196,7 +196,7 @@
 	__IXGBE_HANG_CHECK_ARMED,
 	__IXGBE_RX_RSC_ENABLED,
 	__IXGBE_RX_CSUM_UDP_ZERO_ERR,
-	__IXGBE_RX_FCOE_BUFSZ,
+	__IXGBE_RX_FCOE,
 };
 
 #define check_for_tx_hang(ring) \
@@ -290,7 +290,7 @@
 #if defined(IXGBE_FCOE) && (PAGE_SIZE < 8192)
 static inline unsigned int ixgbe_rx_pg_order(struct ixgbe_ring *ring)
 {
-	return test_bit(__IXGBE_RX_FCOE_BUFSZ, &ring->state) ? 1 : 0;
+	return test_bit(__IXGBE_RX_FCOE, &ring->state) ? 1 : 0;
 }
 #else
 #define ixgbe_rx_pg_order(_ring) 0
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index af1a531..c377706 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -634,7 +634,7 @@
 			f = &adapter->ring_feature[RING_F_FCOE];
 			if ((rxr_idx >= f->mask) &&
 			    (rxr_idx < f->mask + f->indices))
-				set_bit(__IXGBE_RX_FCOE_BUFSZ, &ring->state);
+				set_bit(__IXGBE_RX_FCOE, &ring->state);
 		}
 
 #endif /* IXGBE_FCOE */
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index cbb05d6..18ca3bc 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1058,17 +1058,17 @@
 #ifdef IXGBE_FCOE
 /**
  * ixgbe_rx_is_fcoe - check the rx desc for incoming pkt type
- * @adapter: address of board private structure
+ * @ring: structure containing ring specific data
  * @rx_desc: advanced rx descriptor
  *
  * Returns : true if it is FCoE pkt
  */
-static inline bool ixgbe_rx_is_fcoe(struct ixgbe_adapter *adapter,
+static inline bool ixgbe_rx_is_fcoe(struct ixgbe_ring *ring,
 				    union ixgbe_adv_rx_desc *rx_desc)
 {
 	__le16 pkt_info = rx_desc->wb.lower.lo_dword.hs_rss.pkt_info;
 
-	return (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) &&
+	return test_bit(__IXGBE_RX_FCOE, &ring->state) &&
 	       ((pkt_info & cpu_to_le16(IXGBE_RXDADV_PKTTYPE_ETQF_MASK)) ==
 		(cpu_to_le16(IXGBE_ETQF_FILTER_FCOE <<
 			     IXGBE_RXDADV_PKTTYPE_ETQF_SHIFT)));
@@ -1549,6 +1549,12 @@
 		skb->truesize -= ixgbe_rx_bufsz(rx_ring);
 	}
 
+#ifdef IXGBE_FCOE
+	/* do not attempt to pad FCoE Frames as this will disrupt DDP */
+	if (ixgbe_rx_is_fcoe(rx_ring, rx_desc))
+		return false;
+
+#endif
 	/* if skb_pad returns an error the skb was freed */
 	if (unlikely(skb->len < 60)) {
 		int pad_len = 60 - skb->len;
@@ -1775,7 +1781,7 @@
 
 #ifdef IXGBE_FCOE
 		/* if ddp, not passing to ULD unless for FCP_RSP or error */
-		if (ixgbe_rx_is_fcoe(adapter, rx_desc)) {
+		if (ixgbe_rx_is_fcoe(rx_ring, rx_desc)) {
 			ddp_bytes = ixgbe_fcoe_ddp(adapter, rx_desc, skb);
 			if (!ddp_bytes) {
 				dev_kfree_skb_any(skb);