net/mlx4_en: Avoid calling bswap in tx fast path

- doorbell_qpn is stored in the cpu_to_be32() way to avoid bswap() in fast
  path.
- mdev->mr.key stored in ring->mr_key to also avoid bswap() and access to
  cold cache line.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 12 insertions, 8 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index eaf23eb7266a..322cda32ef80 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -195,7 +195,8 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
         memset(ring->buf, 0, ring->buf_size);
 
         ring->qp_state = MLX4_QP_STATE_RST;
-        ring->doorbell_qpn = ring->qp.qpn << 8;
+        ring->doorbell_qpn = cpu_to_be32(ring->qp.qpn << 8);
+        ring->mr_key = cpu_to_be32(mdev->mr.key);
 
         mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn,
                                 ring->cqn, user_prio, &ring->context);
@@ -654,7 +655,6 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src,
 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct mlx4_en_priv *priv = netdev_priv(dev);
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct device *ddev = priv->ddev;
         struct mlx4_en_tx_ring *ring;
         struct mlx4_en_tx_desc *tx_desc;
@@ -769,7 +769,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                                 goto tx_drop_unmap;
 
                         data->addr = cpu_to_be64(dma);
-                        data->lkey = cpu_to_be32(mdev->mr.key);
+                        data->lkey = ring->mr_key;
                         wmb();
                         data->byte_count = cpu_to_be32(skb_frag_size(frag));
                         --data;
@@ -787,7 +787,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                                 goto tx_drop_unmap;
 
                         data->addr = cpu_to_be64(dma);
-                        data->lkey = cpu_to_be32(mdev->mr.key);
+                        data->lkey = ring->mr_key;
                         wmb();
                         data->byte_count = cpu_to_be32(byte_count);
                 }
@@ -879,9 +879,12 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
         send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue);
 
+        real_size = (real_size / 16) & 0x3f;
+
         if (ring->bf_enabled && desc_size <= MAX_BF && !bounce &&
             !vlan_tx_tag_present(skb) && send_doorbell) {
-                tx_desc->ctrl.bf_qpn |= cpu_to_be32(ring->doorbell_qpn);
+                tx_desc->ctrl.bf_qpn = ring->doorbell_qpn |
+                                       cpu_to_be32(real_size);
 
                 op_own |= htonl((bf_index & 0xffff) << 8);
                 /* Ensure new descriptor hits memory
@@ -911,8 +914,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                 tx_desc->ctrl.owner_opcode = op_own;
                 if (send_doorbell) {
                         wmb();
-                        iowrite32be(ring->doorbell_qpn,
-                                    ring->bf.uar->map + MLX4_SEND_DOORBELL);
+                        iowrite32(ring->doorbell_qpn,
+                                  ring->bf.uar->map + MLX4_SEND_DOORBELL);
                 } else {
                         ring->xmit_more++;
                 }
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index b7bde95e05fe..ab34461e628c 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -279,7 +279,8 @@ struct mlx4_en_tx_ring {
         u16                     stride;
         u16                     cqn;    /* index of port CQ associated with this ring */
         u32                     buf_size;
-        u32                     doorbell_qpn;
+        __be32                  doorbell_qpn;
+        __be32                  mr_key;
         void                    *buf;
         struct mlx4_en_tx_info  *tx_info;
         u8                      *bounce_buf;