r8169: improve rtl8169_start_xmit

Only call rtl8169_xmit_frags() if the skb is actually fragmented.
This avoid a small overhead for non-fragmented skb's, and it allows
to simplify rtl8169_xmit_frags() a little.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index cc4b6fd..f081007 100644 (file)
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4087,12 +4087,10 @@ static int rtl8169_xmit_frags(struct rtl8169_private *tp, struct sk_buff *skb,
                tp->tx_skb[entry].len = len;
        }
 
-       if (cur_frag) {
-               tp->tx_skb[entry].skb = skb;
-               txd->opts1 |= cpu_to_le32(LastFrag);
-       }
+       tp->tx_skb[entry].skb = skb;
+       txd->opts1 |= cpu_to_le32(LastFrag);
 
-       return cur_frag;
+       return 0;
 
 err_out:
        rtl8169_tx_clear_range(tp, tp->cur_tx + 1, cur_frag);
@@ -4217,6 +4215,7 @@ static void rtl8169_doorbell(struct rtl8169_private *tp)
 static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
                                      struct net_device *dev)
 {
+       unsigned int frags = skb_shinfo(skb)->nr_frags;
        struct rtl8169_private *tp = netdev_priv(dev);
        unsigned int entry = tp->cur_tx % NUM_TX_DESC;
        struct TxDesc *txd = tp->TxDescArray + entry;
@@ -4225,9 +4224,8 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
        u32 opts[2], len;
        bool stop_queue;
        bool door_bell;
-       int frags;
 
-       if (unlikely(!rtl_tx_slots_avail(tp, skb_shinfo(skb)->nr_frags))) {
+       if (unlikely(!rtl_tx_slots_avail(tp, frags))) {
                netif_err(tp, drv, dev, "BUG! Tx Ring full when queue awake!\n");
                goto err_stop_0;
        }
@@ -4256,14 +4254,13 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
        tp->tx_skb[entry].len = len;
        txd->addr = cpu_to_le64(mapping);
 
-       frags = rtl8169_xmit_frags(tp, skb, opts);
-       if (frags < 0)
-               goto err_dma_1;
-       else if (frags)
-               opts[0] |= FirstFrag;
-       else {
+       if (!frags) {
                opts[0] |= FirstFrag | LastFrag;
                tp->tx_skb[entry].skb = skb;
+       } else {
+               if (rtl8169_xmit_frags(tp, skb, opts))
+                       goto err_dma_1;
+               opts[0] |= FirstFrag;
        }
 
        txd->opts2 = cpu_to_le32(opts[1]);