be2net: Fix to trim skb for padded vlan packets to workaround an ASIC Bug
Somnath Kotur [Tue, 26 Jun 2012 22:32:10 +0000 (22:32 +0000)]
commit 93040ae5cc8dcc893eca4a4366dc8415af278edf upstream.

Fixed spelling error in a comment as pointed out by DaveM.
Also refactored existing code a bit to provide placeholders for another ASIC
Bug workaround that will be checked-in soon after this.

Signed-off-by: Somnath Kotur <somnath.kotur@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Jacek Luczak <difrost.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/emulex/benet/be.h
drivers/net/ethernet/emulex/benet/be_main.c

index 9576ac0..dcb02c2 100644 (file)
@@ -536,6 +536,11 @@ static inline void be_check_sriov_fn_type(struct be_adapter *adapter)
        adapter->is_virtfn = (sli_intf & SLI_INTF_FT_MASK) ? 1 : 0;
 }
 
+static inline bool is_ipv4_pkt(struct sk_buff *skb)
+{
+       return skb->protocol == ntohs(ETH_P_IP) && ip_hdr(skb)->version == 4;
+}
+
 static inline void be_vf_eth_addr_generate(struct be_adapter *adapter, u8 *mac)
 {
        u32 addr;
index 1bbf6b3..ef1f940 100644 (file)
@@ -571,6 +571,11 @@ static inline u16 be_get_tx_vlan_tag(struct be_adapter *adapter,
        return vlan_tag;
 }
 
+static int be_vlan_tag_chk(struct be_adapter *adapter, struct sk_buff *skb)
+{
+       return vlan_tx_tag_present(skb) || adapter->pvid;
+}
+
 static void wrb_fill_hdr(struct be_adapter *adapter, struct be_eth_hdr_wrb *hdr,
                struct sk_buff *skb, u32 wrb_cnt, u32 len)
 {
@@ -698,33 +703,56 @@ dma_err:
        return 0;
 }
 
+static struct sk_buff *be_insert_vlan_in_pkt(struct be_adapter *adapter,
+                                            struct sk_buff *skb)
+{
+       u16 vlan_tag = 0;
+
+       skb = skb_share_check(skb, GFP_ATOMIC);
+       if (unlikely(!skb))
+               return skb;
+
+       if (vlan_tx_tag_present(skb)) {
+               vlan_tag = be_get_tx_vlan_tag(adapter, skb);
+               __vlan_put_tag(skb, vlan_tag);
+               skb->vlan_tci = 0;
+       }
+
+       return skb;
+}
+
 static netdev_tx_t be_xmit(struct sk_buff *skb,
                        struct net_device *netdev)
 {
        struct be_adapter *adapter = netdev_priv(netdev);
        struct be_tx_obj *txo = &adapter->tx_obj[skb_get_queue_mapping(skb)];
        struct be_queue_info *txq = &txo->q;
+       struct iphdr *ip = NULL;
        u32 wrb_cnt = 0, copied = 0;
-       u32 start = txq->head;
+       u32 start = txq->head, eth_hdr_len;
        bool dummy_wrb, stopped = false;
 
-       /* For vlan tagged pkts, BE
-        * 1) calculates checksum even when CSO is not requested
-        * 2) calculates checksum wrongly for padded pkt less than
-        * 60 bytes long.
-        * As a workaround disable TX vlan offloading in such cases.
+       eth_hdr_len = ntohs(skb->protocol) == ETH_P_8021Q ?
+               VLAN_ETH_HLEN : ETH_HLEN;
+
+       /* HW has a bug which considers padding bytes as legal
+        * and modifies the IPv4 hdr's 'tot_len' field
         */
-       if (unlikely(vlan_tx_tag_present(skb) &&
-                    (skb->ip_summed != CHECKSUM_PARTIAL || skb->len <= 60))) {
-               skb = skb_share_check(skb, GFP_ATOMIC);
-               if (unlikely(!skb))
-                       goto tx_drop;
+       if (skb->len <= 60 && be_vlan_tag_chk(adapter, skb) &&
+                       is_ipv4_pkt(skb)) {
+               ip = (struct iphdr *)ip_hdr(skb);
+               pskb_trim(skb, eth_hdr_len + ntohs(ip->tot_len));
+       }
 
-               skb = __vlan_put_tag(skb, be_get_tx_vlan_tag(adapter, skb));
+       /* HW has a bug wherein it will calculate CSUM for VLAN
+        * pkts even though it is disabled.
+        * Manually insert VLAN in pkt.
+        */
+       if (skb->ip_summed != CHECKSUM_PARTIAL &&
+                       be_vlan_tag_chk(adapter, skb)) {
+               skb = be_insert_vlan_in_pkt(adapter, skb);
                if (unlikely(!skb))
                        goto tx_drop;
-
-               skb->vlan_tci = 0;
        }
 
        wrb_cnt = wrb_cnt_for_skb(adapter, skb, &dummy_wrb);