fm10k: Add skb->xmit_more support

This change adds support for skb->xmit_more based on the changes that were
made to igb to support the feature.  The main changes are moving up the
check for maybe_stop_tx so that we can check netif_xmit_stopped to determine
if we must write the tail because we can add no further buffers.

Acked-by: Matthew Vick <matthew.vick@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 31 deletions

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index 9d7118a0d67a..e645af412e76 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -929,6 +929,30 @@ static bool fm10k_tx_desc_push(struct fm10k_ring *tx_ring,
         return i == tx_ring->count;
 }
 
+static int __fm10k_maybe_stop_tx(struct fm10k_ring *tx_ring, u16 size)
+{
+        netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
+
+        smp_mb();
+
+        /* We need to check again in a case another CPU has just
+         * made room available. */
+        if (likely(fm10k_desc_unused(tx_ring) < size))
+                return -EBUSY;
+
+        /* A reprieve! - use start_queue because it doesn't call schedule */
+        netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
+        ++tx_ring->tx_stats.restart_queue;
+        return 0;
+}
+
+static inline int fm10k_maybe_stop_tx(struct fm10k_ring *tx_ring, u16 size)
+{
+        if (likely(fm10k_desc_unused(tx_ring) >= size))
+                return 0;
+        return __fm10k_maybe_stop_tx(tx_ring, size);
+}
+
 static void fm10k_tx_map(struct fm10k_ring *tx_ring,
                          struct fm10k_tx_buffer *first)
 {
@@ -1022,13 +1046,18 @@ static void fm10k_tx_map(struct fm10k_ring *tx_ring,
 
         tx_ring->next_to_use = i;
 
+        /* Make sure there is space in the ring for the next send. */
+        fm10k_maybe_stop_tx(tx_ring, DESC_NEEDED);
+
         /* notify HW of packet */
-        writel(i, tx_ring->tail);
+        if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) {
+                writel(i, tx_ring->tail);
 
-        /* we need this if more than one processor can write to our tail
-         * at a time, it synchronizes IO on IA64/Altix systems
-         */
-        mmiowb();
+                /* we need this if more than one processor can write to our tail
+                 * at a time, it synchronizes IO on IA64/Altix systems
+                 */
+                mmiowb();
+        }
 
         return;
 dma_error:
@@ -1048,30 +1077,6 @@ dma_error:
         tx_ring->next_to_use = i;
 }
 
-static int __fm10k_maybe_stop_tx(struct fm10k_ring *tx_ring, u16 size)
-{
-        netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
-
-        smp_mb();
-
-        /* We need to check again in a case another CPU has just
-         * made room available. */
-        if (likely(fm10k_desc_unused(tx_ring) < size))
-                return -EBUSY;
-
-        /* A reprieve! - use start_queue because it doesn't call schedule */
-        netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
-        ++tx_ring->tx_stats.restart_queue;
-        return 0;
-}
-
-static inline int fm10k_maybe_stop_tx(struct fm10k_ring *tx_ring, u16 size)
-{
-        if (likely(fm10k_desc_unused(tx_ring) >= size))
-                return 0;
-        return __fm10k_maybe_stop_tx(tx_ring, size);
-}
-
 netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,
                                   struct fm10k_ring *tx_ring)
 {
@@ -1116,8 +1121,6 @@ netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,
 
         fm10k_tx_map(tx_ring, first);
 
-        fm10k_maybe_stop_tx(tx_ring, DESC_NEEDED);
-
         return NETDEV_TX_OK;
 
 out_drop: