cxgb4: Don't assume LSO only uses SGL path in t4_eth_xmit()

Also, modify is_eth_imm() to return header length so it doesn't
have to be recomputed in calc_tx_flits().

Based on original work by Mike Werner <werner@chelsio.com>

Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index 23dbe28f8aca1135587c29c8014a28c7dc733a2e..af76b25bb6064b202738c2720120eb1de7718d7a 100644 (file)
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -706,11 +706,17 @@ static inline unsigned int flits_to_desc(unsigned int n)
  *     @skb: the packet
  *
  *     Returns whether an Ethernet packet is small enough to fit as
- *     immediate data.
+ *     immediate data. Return value corresponds to headroom required.
  */
 static inline int is_eth_imm(const struct sk_buff *skb)
 {
-       return skb->len <= MAX_IMM_TX_PKT_LEN - sizeof(struct cpl_tx_pkt);
+       int hdrlen = skb_shinfo(skb)->gso_size ?
+                       sizeof(struct cpl_tx_pkt_lso_core) : 0;
+
+       hdrlen += sizeof(struct cpl_tx_pkt);
+       if (skb->len <= MAX_IMM_TX_PKT_LEN - hdrlen)
+               return hdrlen;
+       return 0;
 }
 
 /**
@@ -723,9 +729,10 @@ static inline int is_eth_imm(const struct sk_buff *skb)
 static inline unsigned int calc_tx_flits(const struct sk_buff *skb)
 {
        unsigned int flits;
+       int hdrlen = is_eth_imm(skb);
 
-       if (is_eth_imm(skb))
-               return DIV_ROUND_UP(skb->len + sizeof(struct cpl_tx_pkt), 8);
+       if (hdrlen)
+               return DIV_ROUND_UP(skb->len + hdrlen, sizeof(__be64));
 
        flits = sgl_len(skb_shinfo(skb)->nr_frags + 1) + 4;
        if (skb_shinfo(skb)->gso_size)
@@ -971,6 +978,7 @@ static inline void txq_advance(struct sge_txq *q, unsigned int n)
  */
 netdev_tx_t t4_eth_xmit(struct sk_buff *skb, struct net_device *dev)
 {
+       int len;
        u32 wr_mid;
        u64 cntrl, *end;
        int qidx, credits;
@@ -982,6 +990,7 @@ netdev_tx_t t4_eth_xmit(struct sk_buff *skb, struct net_device *dev)
        struct cpl_tx_pkt_core *cpl;
        const struct skb_shared_info *ssi;
        dma_addr_t addr[MAX_SKB_FRAGS + 1];
+       bool immediate = false;
 
        /*
         * The chip min packet length is 10 octets but play safe and reject
@@ -1011,7 +1020,10 @@ out_free:        dev_kfree_skb(skb);
                return NETDEV_TX_BUSY;
        }
 
-       if (!is_eth_imm(skb) &&
+       if (is_eth_imm(skb))
+               immediate = true;
+
+       if (!immediate &&
            unlikely(map_skb(adap->pdev_dev, skb, addr) < 0)) {
                q->mapping_err++;
                goto out_free;
@@ -1028,6 +1040,8 @@ out_free: dev_kfree_skb(skb);
        wr->r3 = cpu_to_be64(0);
        end = (u64 *)wr + flits;
 
+       len = immediate ? skb->len : 0;
+       len += sizeof(*cpl);
        ssi = skb_shinfo(skb);
        if (ssi->gso_size) {
                struct cpl_tx_pkt_lso *lso = (void *)wr;
@@ -1035,8 +1049,9 @@ out_free: dev_kfree_skb(skb);
                int l3hdr_len = skb_network_header_len(skb);
                int eth_xtra_len = skb_network_offset(skb) - ETH_HLEN;
 
+               len += sizeof(*lso);
                wr->op_immdlen = htonl(FW_WR_OP(FW_ETH_TX_PKT_WR) |
-                                      FW_WR_IMMDLEN(sizeof(*lso)));
+                                      FW_WR_IMMDLEN(len));
                lso->c.lso_ctrl = htonl(LSO_OPCODE(CPL_TX_PKT_LSO) |
                                        LSO_FIRST_SLICE | LSO_LAST_SLICE |
                                        LSO_IPV6(v6) |
@@ -1054,9 +1069,6 @@ out_free: dev_kfree_skb(skb);
                q->tso++;
                q->tx_cso += ssi->gso_segs;
        } else {
-               int len;
-
-               len = is_eth_imm(skb) ? skb->len + sizeof(*cpl) : sizeof(*cpl);
                wr->op_immdlen = htonl(FW_WR_OP(FW_ETH_TX_PKT_WR) |
                                       FW_WR_IMMDLEN(len));
                cpl = (void *)(wr + 1);
@@ -1078,7 +1090,7 @@ out_free: dev_kfree_skb(skb);
        cpl->len = htons(skb->len);
        cpl->ctrl1 = cpu_to_be64(cntrl);
 
-       if (is_eth_imm(skb)) {
+       if (immediate) {
                inline_tx_skb(skb, &q->q, cpl + 1);
                dev_kfree_skb(skb);
        } else {