i40evf: remove open-coded skb_cow_head

[pandora-kernel.git] / drivers / net / ethernet / intel / i40evf / i40e_txrx.c

diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index b1d87c6..b9f50f4 100644 (file)
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -169,6 +169,20 @@ static bool i40e_check_tx_hang(struct i40e_ring *tx_ring)
        return ret;
 }
 
+/**
+ * i40e_get_head - Retrieve head from head writeback
+ * @tx_ring:  tx ring to fetch head of
+ *
+ * Returns value of Tx ring head based on value stored
+ * in head write-back location
+ **/
+static inline u32 i40e_get_head(struct i40e_ring *tx_ring)
+{
+       void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count;
+
+       return le32_to_cpu(*(volatile __le32 *)head);
+}
+
 /**
  * i40e_clean_tx_irq - Reclaim resources after transmit completes
  * @tx_ring:  tx ring to clean
@@ -180,6 +194,7 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
 {
        u16 i = tx_ring->next_to_clean;
        struct i40e_tx_buffer *tx_buf;
+       struct i40e_tx_desc *tx_head;
        struct i40e_tx_desc *tx_desc;
        unsigned int total_packets = 0;
        unsigned int total_bytes = 0;
@@ -188,6 +203,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
        tx_desc = I40E_TX_DESC(tx_ring, i);
        i -= tx_ring->count;
 
+       tx_head = I40E_TX_DESC(tx_ring, i40e_get_head(tx_ring));
+
        do {
                struct i40e_tx_desc *eop_desc = tx_buf->next_to_watch;
 
@@ -198,9 +215,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
                /* prevent any other reads prior to eop_desc */
                read_barrier_depends();
 
-               /* if the descriptor isn't done, no work yet to do */
-               if (!(eop_desc->cmd_type_offset_bsz &
-                     cpu_to_le64(I40E_TX_DESC_DTYPE_DESC_DONE)))
+               /* we have caught up to head, no work left to do */
+               if (tx_head == tx_desc)
                        break;
 
                /* clear next_to_watch to prevent false hangs */
@@ -432,6 +448,10 @@ int i40evf_setup_tx_descriptors(struct i40e_ring *tx_ring)
 
        /* round up to nearest 4K */
        tx_ring->size = tx_ring->count * sizeof(struct i40e_tx_desc);
+       /* add u32 for head writeback, align after this takes care of
+        * guaranteeing this is at least one cache line in size
+        */
+       tx_ring->size += sizeof(u32);
        tx_ring->size = ALIGN(tx_ring->size, 4096);
        tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
                                           &tx_ring->dma, GFP_KERNEL);
@@ -1094,20 +1114,18 @@ static int i40e_tso(struct i40e_ring *tx_ring, struct sk_buff *skb,
                    u64 *cd_type_cmd_tso_mss, u32 *cd_tunneling)
 {
        u32 cd_cmd, cd_tso_len, cd_mss;
+       struct ipv6hdr *ipv6h;
        struct tcphdr *tcph;
        struct iphdr *iph;
        u32 l4len;
        int err;
-       struct ipv6hdr *ipv6h;
 
        if (!skb_is_gso(skb))
                return 0;
 
-       if (skb_header_cloned(skb)) {
-               err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
-               if (err)
-                       return err;
-       }
+       err = skb_cow_head(skb, 0);
+       if (err < 0)
+               return err;
 
        if (protocol == htons(ETH_P_IP)) {
                iph = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
@@ -1266,7 +1284,8 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring,
        struct i40e_tx_context_desc *context_desc;
        int i = tx_ring->next_to_use;
 
-       if (!cd_type_cmd_tso_mss && !cd_tunneling && !cd_l2tag2)
+       if ((cd_type_cmd_tso_mss == I40E_TX_DESC_DTYPE_CONTEXT) &&
+           !cd_tunneling && !cd_l2tag2)
                return;
 
        /* grab the next descriptor */
@@ -1377,9 +1396,23 @@ static void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
                tx_bi = &tx_ring->tx_bi[i];
        }
 
-       tx_desc->cmd_type_offset_bsz =
-               build_ctob(td_cmd, td_offset, size, td_tag) |
-               cpu_to_le64((u64)I40E_TXD_CMD << I40E_TXD_QW1_CMD_SHIFT);
+       /* Place RS bit on last descriptor of any packet that spans across the
+        * 4th descriptor (WB_STRIDE aka 0x3) in a 64B cacheline.
+        */
+#define WB_STRIDE 0x3
+       if (((i & WB_STRIDE) != WB_STRIDE) &&
+           (first <= &tx_ring->tx_bi[i]) &&
+           (first >= &tx_ring->tx_bi[i & ~WB_STRIDE])) {
+               tx_desc->cmd_type_offset_bsz =
+                       build_ctob(td_cmd, td_offset, size, td_tag) |
+                       cpu_to_le64((u64)I40E_TX_DESC_CMD_EOP <<
+                                        I40E_TXD_QW1_CMD_SHIFT);
+       } else {
+               tx_desc->cmd_type_offset_bsz =
+                       build_ctob(td_cmd, td_offset, size, td_tag) |
+                       cpu_to_le64((u64)I40E_TXD_CMD <<
+                                        I40E_TXD_QW1_CMD_SHIFT);
+       }
 
        netdev_tx_sent_queue(netdev_get_tx_queue(tx_ring->netdev,
                                                 tx_ring->queue_index),