net/mlx4_en: Enable the compiler to make is_inline() inlined

Reorganize code to call is_inline() once, so compiler can inline it

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>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 2c03b55..f0080c5 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -531,29 +531,32 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
        return ring->buf + index * TXBB_SIZE;
 }
 
+/* Decide if skb can be inlined in tx descriptor to avoid dma mapping
+ *
+ * It seems strange we do not simply use skb_copy_bits().
+ * This would allow to inline all skbs iff skb->len <= inline_thold
+ *
+ * Note that caller already checked skb was not a gso packet
+ */
 static bool is_inline(int inline_thold, const struct sk_buff *skb,
                      const struct skb_shared_info *shinfo,
                      void **pfrag)
 {
        void *ptr;
 
-       if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) {
-               if (shinfo->nr_frags == 1) {
-                       ptr = skb_frag_address_safe(&shinfo->frags[0]);
-                       if (unlikely(!ptr))
-                               return 0;
-
-                       if (pfrag)
-                               *pfrag = ptr;
+       if (skb->len > inline_thold || !inline_thold)
+               return false;
 
-                       return 1;
-               } else if (unlikely(shinfo->nr_frags))
-                       return 0;
-               else
-                       return 1;
+       if (shinfo->nr_frags == 1) {
+               ptr = skb_frag_address_safe(&shinfo->frags[0]);
+               if (unlikely(!ptr))
+                       return false;
+               *pfrag = ptr;
+               return true;
        }
-
-       return 0;
+       if (shinfo->nr_frags)
+               return false;
+       return true;
 }
 
 static int inline_size(const struct sk_buff *skb)
@@ -570,12 +573,15 @@ static int inline_size(const struct sk_buff *skb)
 static int get_real_size(const struct sk_buff *skb,
                         const struct skb_shared_info *shinfo,
                         struct net_device *dev,
-                        int *lso_header_size)
+                        int *lso_header_size,
+                        bool *inline_ok,
+                        void **pfrag)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int real_size;
 
        if (shinfo->gso_size) {
+               *inline_ok = false;
                if (skb->encapsulation)
                        *lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
                else
@@ -595,10 +601,14 @@ static int get_real_size(const struct sk_buff *skb,
                }
        } else {
                *lso_header_size = 0;
-               if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL))
-                       real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE;
-               else
+               *inline_ok = is_inline(priv->prof->inline_thold, skb,
+                                      shinfo, pfrag);
+
+               if (*inline_ok)
                        real_size = inline_size(skb);
+               else
+                       real_size = CTRL_SIZE +
+                                   (shinfo->nr_frags + 1) * DS_SIZE;
        }
 
        return real_size;
@@ -694,9 +704,10 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        u16 vlan_tag = 0;
        int i_frag;
        int lso_header_size;
-       void *fragptr;
+       void *fragptr = NULL;
        bool bounce = false;
        bool send_doorbell;
+       bool inline_ok;
        u32 ring_cons;
 
        if (!priv->port_up)
@@ -708,7 +719,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        /* fetch ring->cons far ahead before needing it to avoid stall */
        ring_cons = ACCESS_ONCE(ring->cons);
 
-       real_size = get_real_size(skb, shinfo, dev, &lso_header_size);
+       real_size = get_real_size(skb, shinfo, dev, &lso_header_size,
+                                 &inline_ok, &fragptr);
        if (unlikely(!real_size))
                goto tx_drop;
 
@@ -781,15 +793,15 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        /* valid only for none inline segments */
        tx_info->data_offset = (void *)data - (void *)tx_desc;
 
+       tx_info->inl = inline_ok;
+
        tx_info->linear = (lso_header_size < skb_headlen(skb) &&
-                          !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0;
+                          !inline_ok) ? 1 : 0;
 
        tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
        data += tx_info->nr_maps - 1;
 
-       if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) {
-               tx_info->inl = 1;
-       } else {
+       if (!tx_info->inl) {
                dma_addr_t dma = 0;
                u32 byte_count = 0;
 
@@ -827,7 +839,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                        wmb();
                        data->byte_count = cpu_to_be32(byte_count);
                }
-               tx_info->inl = 0;
                /* tx completion can avoid cache line miss for common cases */
                tx_info->map0_dma = dma;
                tx_info->map0_byte_count = byte_count;
@@ -899,11 +910,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
        AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
 
-       if (tx_info->inl) {
+       if (tx_info->inl)
                build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
                                 tx_ind, fragptr);
-               tx_info->inl = 1;
-       }
 
        if (skb->encapsulation) {
                struct iphdr *ipv4 = (struct iphdr *)skb_inner_network_header(skb);