r8169: add support for xmit_more

Delay update of hw tail descriptor if we know that another skb is going
to be sent.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 14a1c5cec3a5..3a280598a15a 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -7049,6 +7049,7 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
         u32 status, len;
         u32 opts[2];
         int frags;
+        bool stop_queue;
 
         if (unlikely(!TX_FRAGS_READY_FOR(tp, skb_shinfo(skb)->nr_frags))) {
                 netif_err(tp, drv, dev, "BUG! Tx Ring full when queue awake!\n");
@@ -7105,11 +7106,16 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
         tp->cur_tx += frags + 1;
 
-        RTL_W8(TxPoll, NPQ);
+        stop_queue = !TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS);
 
-        mmiowb();
+        if (!skb->xmit_more || stop_queue ||
+            netif_xmit_stopped(netdev_get_tx_queue(dev, 0))) {
+                RTL_W8(TxPoll, NPQ);
+
+                mmiowb();
+        }
 
-        if (!TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) {
+        if (stop_queue) {
                 /* Avoid wrongly optimistic queue wake-up: rtl_tx thread must
                  * not miss a ring update when it notices a stopped queue.
                  */