net/mlx4_en: Saving mem access on data path

Localized the pdev->dev, and using dma_map instead of pci_map
There are multiple map/unmap operations on data path,
optimizing those by saving redundant pointer access.
Those places were identified as hot-spots when running kernel profiling
during some benchmarks.
The fixes had most impact when testing packet rate with small packets,
reducing several % from CPU load, and in some case being the difference
between reaching wire speed or being CPU bound.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 13 insertions, 16 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 9fe4f94c6da7..31b455a49273 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -1062,6 +1062,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
         memset(priv, 0, sizeof(struct mlx4_en_priv));
         priv->dev = dev;
         priv->mdev = mdev;
+        priv->ddev = &mdev->pdev->dev;
         priv->prof = prof;
         priv->port = port;
         priv->port_up = false;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index d703ef2c9c91..c881712b7492 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -48,7 +48,6 @@ static int mlx4_en_alloc_frag(struct mlx4_en_priv *priv,
                               struct mlx4_en_rx_alloc *ring_alloc,
                               int i)
 {
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct mlx4_en_frag_info *frag_info = &priv->frag_info[i];
         struct mlx4_en_rx_alloc *page_alloc = &ring_alloc[i];
         struct page *page;
@@ -72,7 +71,7 @@ static int mlx4_en_alloc_frag(struct mlx4_en_priv *priv,
                 skb_frags[i].offset = page_alloc->offset;
                 page_alloc->offset += frag_info->frag_stride;
         }
-        dma = pci_map_single(mdev->pdev, page_address(skb_frags[i].page) +
+        dma = dma_map_single(priv->ddev, page_address(skb_frags[i].page) +
                              skb_frags[i].offset, frag_info->frag_size,
                              PCI_DMA_FROMDEVICE);
         rx_desc->data[i].addr = cpu_to_be64(dma);
@@ -186,7 +185,6 @@ static void mlx4_en_free_rx_desc(struct mlx4_en_priv *priv,
                                  struct mlx4_en_rx_ring *ring,
                                  int index)
 {
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct page_frag *skb_frags;
         struct mlx4_en_rx_desc *rx_desc = ring->buf + (index << ring->log_stride);
         dma_addr_t dma;
@@ -198,7 +196,7 @@ static void mlx4_en_free_rx_desc(struct mlx4_en_priv *priv,
                 dma = be64_to_cpu(rx_desc->data[nr].addr);
 
                 en_dbg(DRV, priv, "Unmapping buffer at dma:0x%llx\n", (u64) dma);
-                pci_unmap_single(mdev->pdev, dma, skb_frags[nr].size,
+                dma_unmap_single(priv->ddev, dma, skb_frags[nr].size,
                                  PCI_DMA_FROMDEVICE);
                 put_page(skb_frags[nr].page);
         }
@@ -412,7 +410,6 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv,
                                     int length)
 {
         struct skb_frag_struct *skb_frags_rx = skb_shinfo(skb)->frags;
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct mlx4_en_frag_info *frag_info;
         int nr;
         dma_addr_t dma;
@@ -435,7 +432,7 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv,
                         goto fail;
 
                 /* Unmap buffer */
-                pci_unmap_single(mdev->pdev, dma, skb_frag_size(&skb_frags_rx[nr]),
+                dma_unmap_single(priv->ddev, dma, skb_frag_size(&skb_frags_rx[nr]),
                                  PCI_DMA_FROMDEVICE);
         }
         /* Adjust size of last fragment to match actual length */
@@ -461,7 +458,6 @@ static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv,
                                       struct mlx4_en_rx_alloc *page_alloc,
                                       unsigned int length)
 {
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct sk_buff *skb;
         void *va;
         int used_frags;
@@ -483,10 +479,10 @@ static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv,
                 /* We are copying all relevant data to the skb - temporarily
                  * synch buffers for the copy */
                 dma = be64_to_cpu(rx_desc->data[0].addr);
-                dma_sync_single_for_cpu(&mdev->pdev->dev, dma, length,
+                dma_sync_single_for_cpu(priv->ddev, dma, length,
                                         DMA_FROM_DEVICE);
                 skb_copy_to_linear_data(skb, va, length);
-                dma_sync_single_for_device(&mdev->pdev->dev, dma, length,
+                dma_sync_single_for_device(priv->ddev, dma, length,
                                            DMA_FROM_DEVICE);
                 skb->tail += length;
         } else {
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 50b3fa5212ed..008f0af5cc8b 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -198,7 +198,6 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
                                 struct mlx4_en_tx_ring *ring,
                                 int index, u8 owner)
 {
-        struct mlx4_en_dev *mdev = priv->mdev;
         struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
         struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
         struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset;
@@ -214,7 +213,7 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
         if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
                 if (!tx_info->inl) {
                         if (tx_info->linear) {
-                                pci_unmap_single(mdev->pdev,
+                                dma_unmap_single(priv->ddev,
                                         (dma_addr_t) be64_to_cpu(data->addr),
                                          be32_to_cpu(data->byte_count),
                                          PCI_DMA_TODEVICE);
@@ -223,7 +222,7 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
 
                         for (i = 0; i < frags; i++) {
                                 frag = &skb_shinfo(skb)->frags[i];
-                                pci_unmap_page(mdev->pdev,
+                                dma_unmap_page(priv->ddev,
                                         (dma_addr_t) be64_to_cpu(data[i].addr),
                                         skb_frag_size(frag), PCI_DMA_TODEVICE);
                         }
@@ -241,7 +240,7 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
                         }
 
                         if (tx_info->linear) {
-                                pci_unmap_single(mdev->pdev,
+                                dma_unmap_single(priv->ddev,
                                         (dma_addr_t) be64_to_cpu(data->addr),
                                          be32_to_cpu(data->byte_count),
                                          PCI_DMA_TODEVICE);
@@ -253,7 +252,7 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
                                 if ((void *) data >= end)
                                         data = ring->buf;
                                 frag = &skb_shinfo(skb)->frags[i];
-                                pci_unmap_page(mdev->pdev,
+                                dma_unmap_page(priv->ddev,
                                         (dma_addr_t) be64_to_cpu(data->addr),
                                          skb_frag_size(frag), PCI_DMA_TODEVICE);
                                 ++data;
@@ -733,7 +732,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                 /* Map fragments */
                 for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
                         frag = &skb_shinfo(skb)->frags[i];
-                        dma = skb_frag_dma_map(&mdev->dev->pdev->dev, frag,
+                        dma = skb_frag_dma_map(priv->ddev, frag,
                                                0, skb_frag_size(frag),
                                                DMA_TO_DEVICE);
                         data->addr = cpu_to_be64(dma);
@@ -745,7 +744,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
                 /* Map linear part */
                 if (tx_info->linear) {
-                        dma = pci_map_single(mdev->dev->pdev, skb->data + lso_header_size,
+                        dma = dma_map_single(priv->ddev, skb->data + lso_header_size,
                                              skb_headlen(skb) - lso_header_size, PCI_DMA_TODEVICE);
                         data->addr = cpu_to_be64(dma);
                         data->lkey = cpu_to_be32(mdev->mr.key);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index d60335f3c473..a5bb0b7d339a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -482,6 +482,7 @@ struct mlx4_en_priv {
         struct mlx4_en_stat_out_mbox hw_stats;
         int vids[128];
         bool wol;
+        struct device *ddev;
 };
 
 enum mlx4_en_wol {