net: hns3: add linearizing checking for TSO case

HW requires every continuous 8 buffer data to be larger than MSS,
we simplify it by ensuring skb_headlen + the first continuous
7 frags to to be larger than GSO header len + mss, and the
remaining continuous 7 frags to be larger than MSS except the
last 7 frags.

This patch adds hns3_skb_need_linearized to handle it for TSO
case.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 453fdf43136a0f2d61f6212555e7ef5b7b2ec290..944e0aecb816fcbeec17bcfe7fb5bc6e4759646b 100644 (file)
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -1181,6 +1181,47 @@ static int hns3_nic_bd_num(struct sk_buff *skb)
        return bd_num;
 }
 
+static unsigned int hns3_gso_hdr_len(struct sk_buff *skb)
+{
+       if (!skb->encapsulation)
+               return skb_transport_offset(skb) + tcp_hdrlen(skb);
+
+       return skb_inner_transport_offset(skb) + inner_tcp_hdrlen(skb);
+}
+
+/* HW need every continuous 8 buffer data to be larger than MSS,
+ * we simplify it by ensuring skb_headlen + the first continuous
+ * 7 frags to to be larger than gso header len + mss, and the remaining
+ * continuous 7 frags to be larger than MSS except the last 7 frags.
+ */
+static bool hns3_skb_need_linearized(struct sk_buff *skb)
+{
+       int bd_limit = HNS3_MAX_BD_PER_FRAG - 1;
+       unsigned int tot_len = 0;
+       int i;
+
+       for (i = 0; i < bd_limit; i++)
+               tot_len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+       /* ensure headlen + the first 7 frags is greater than mss + header
+        * and the first 7 frags is greater than mss.
+        */
+       if (((tot_len + skb_headlen(skb)) < (skb_shinfo(skb)->gso_size +
+           hns3_gso_hdr_len(skb))) || (tot_len < skb_shinfo(skb)->gso_size))
+               return true;
+
+       /* ensure the remaining continuous 7 buffer is greater than mss */
+       for (i = 0; i < (skb_shinfo(skb)->nr_frags - bd_limit - 1); i++) {
+               tot_len -= skb_frag_size(&skb_shinfo(skb)->frags[i]);
+               tot_len += skb_frag_size(&skb_shinfo(skb)->frags[i + bd_limit]);
+
+               if (tot_len < skb_shinfo(skb)->gso_size)
+                       return true;
+       }
+
+       return false;
+}
+
 static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring,
                                  struct sk_buff **out_skb)
 {
@@ -1194,6 +1235,9 @@ static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring,
        if (unlikely(bd_num > HNS3_MAX_BD_PER_FRAG)) {
                struct sk_buff *new_skb;
 
+               if (skb_is_gso(skb) && !hns3_skb_need_linearized(skb))
+                       goto out;
+
                bd_num = hns3_tx_bd_count(skb->len);
                if (unlikely(ring_space(ring) < bd_num))
                        return -EBUSY;
@@ -1209,6 +1253,7 @@ static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring,
                u64_stats_update_end(&ring->syncp);
        }
 
+out:
        if (unlikely(ring_space(ring) < bd_num))
                return -EBUSY;