net/mlx4_en: Use local var in tx flow for skb_shinfo(skb)

Acces skb_shinfo(skb) once in tx flow.
Also, rename @i variable to @i_frag to avoid confusion, as the "goto
tx_drop_unmap;" relied on this @i variable.

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 99875c8..aa05b09 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -532,13 +532,14 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
 }
 
 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 (skb_shinfo(skb)->nr_frags == 1) {
-                       ptr = skb_frag_address_safe(&skb_shinfo(skb)->frags[0]);
+               if (shinfo->nr_frags == 1) {
+                       ptr = skb_frag_address_safe(&shinfo->frags[0]);
                        if (unlikely(!ptr))
                                return 0;
 
@@ -546,7 +547,7 @@ static bool is_inline(int inline_thold, const struct sk_buff *skb,
                                *pfrag = ptr;
 
                        return 1;
-               } else if (unlikely(skb_shinfo(skb)->nr_frags))
+               } else if (unlikely(shinfo->nr_frags))
                        return 0;
                else
                        return 1;
@@ -567,18 +568,19 @@ 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)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int real_size;
 
-       if (skb_is_gso(skb)) {
+       if (shinfo->gso_size) {
                if (skb->encapsulation)
                        *lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
                else
                        *lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
-               real_size = CTRL_SIZE + skb_shinfo(skb)->nr_frags * DS_SIZE +
+               real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
                        ALIGN(*lso_header_size + 4, DS_SIZE);
                if (unlikely(*lso_header_size != skb_headlen(skb))) {
                        /* We add a segment for the skb linear buffer only if
@@ -593,8 +595,8 @@ static int get_real_size(const struct sk_buff *skb,
                }
        } else {
                *lso_header_size = 0;
-               if (!is_inline(priv->prof->inline_thold, skb, NULL))
-                       real_size = CTRL_SIZE + (skb_shinfo(skb)->nr_frags + 1) * DS_SIZE;
+               if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL))
+                       real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE;
                else
                        real_size = inline_size(skb);
        }
@@ -604,6 +606,7 @@ static int get_real_size(const struct sk_buff *skb,
 
 static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
                             const struct sk_buff *skb,
+                            const struct skb_shared_info *shinfo,
                             int real_size, u16 *vlan_tag,
                             int tx_ind, void *fragptr)
 {
@@ -619,9 +622,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
                               MIN_PKT_LEN - skb->len);
                }
                skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
-               if (skb_shinfo(skb)->nr_frags)
+               if (shinfo->nr_frags)
                        memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr,
-                              skb_frag_size(&skb_shinfo(skb)->frags[0]));
+                              skb_frag_size(&shinfo->frags[0]));
 
        } else {
                inl->byte_count = cpu_to_be32(1 << 31 | spc);
@@ -639,9 +642,10 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
                        inl = (void *) (inl + 1) + spc;
                        skb_copy_from_linear_data_offset(skb, spc, inl + 1,
                                        skb_headlen(skb) - spc);
-                       if (skb_shinfo(skb)->nr_frags)
+                       if (shinfo->nr_frags)
                                memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc,
-                                       fragptr, skb_frag_size(&skb_shinfo(skb)->frags[0]));
+                                      fragptr,
+                                      skb_frag_size(&shinfo->frags[0]));
                }
 
                wmb();
@@ -673,6 +677,7 @@ 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 skb_shared_info *shinfo = skb_shinfo(skb);
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct device *ddev = priv->ddev;
        struct mlx4_en_tx_ring *ring;
@@ -686,7 +691,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        u32 index, bf_index;
        __be32 op_own;
        u16 vlan_tag = 0;
-       int i;
+       int i_frag;
        int lso_header_size;
        void *fragptr;
        bool bounce = false;
@@ -702,7 +707,7 @@ 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, dev, &lso_header_size);
+       real_size = get_real_size(skb, shinfo, dev, &lso_header_size);
        if (unlikely(!real_size))
                goto tx_drop;
 
@@ -776,21 +781,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        tx_info->data_offset = (void *)data - (void *)tx_desc;
 
        tx_info->linear = (lso_header_size < skb_headlen(skb) &&
-                          !is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0;
+                          !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0;
 
-       tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear;
+       tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
        data += tx_info->nr_maps - 1;
 
-       if (is_inline(ring->inline_thold, skb, &fragptr)) {
+       if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) {
                tx_info->inl = 1;
        } else {
                dma_addr_t dma = 0;
                u32 byte_count = 0;
 
                /* Map fragments if any */
-               for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
+               for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) {
                        const struct skb_frag_struct *frag;
-                       frag = &skb_shinfo(skb)->frags[i];
+
+                       frag = &shinfo->frags[i_frag];
                        byte_count = skb_frag_size(frag);
                        dma = skb_frag_dma_map(ddev, frag,
                                               0, byte_count,
@@ -858,6 +864,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
        /* Handle LSO (TSO) packets */
        if (lso_header_size) {
+               int i;
+
                /* Mark opcode as LSO */
                op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
                        ((ring->prod & ring->size) ?
@@ -865,15 +873,16 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
                /* Fill in the LSO prefix */
                tx_desc->lso.mss_hdr_size = cpu_to_be32(
-                       skb_shinfo(skb)->gso_size << 16 | lso_header_size);
+                       shinfo->gso_size << 16 | lso_header_size);
 
                /* Copy headers;
                 * note that we already verified that it is linear */
                memcpy(tx_desc->lso.header, skb->data, lso_header_size);
 
                ring->tso_packets++;
-               i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) +
-                       !!((skb->len - lso_header_size) % skb_shinfo(skb)->gso_size);
+
+               i = ((skb->len - lso_header_size) / shinfo->gso_size) +
+                       !!((skb->len - lso_header_size) % shinfo->gso_size);
                tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size;
                ring->packets += i;
        } else {
@@ -889,7 +898,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
 
        if (tx_info->inl) {
-               build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr);
+               build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
+                                tx_ind, fragptr);
                tx_info->inl = 1;
        }
 
@@ -958,8 +968,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 tx_drop_unmap:
        en_err(priv, "DMA mapping error\n");
 
-       for (i++; i < skb_shinfo(skb)->nr_frags; i++) {
-               data++;
+       while (++i_frag < shinfo->nr_frags) {
+               ++data;
                dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
                               be32_to_cpu(data->byte_count),
                               PCI_DMA_TODEVICE);