1 files changed, 19 insertions, 3 deletions

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 256adbd044f5..cf4897043e83 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -744,6 +744,14 @@ void netvsc_linkstatus_callback(struct net_device *net,
         schedule_delayed_work(&ndev_ctx->dwork, 0);
 }
 
+static void netvsc_comp_ipcsum(struct sk_buff *skb)
+{
+        struct iphdr *iph = (struct iphdr *)skb->data;
+
+        iph->check = 0;
+        iph->check = ip_fast_csum(iph, iph->ihl);
+}
+
 static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
                                              struct netvsc_channel *nvchan)
 {
@@ -770,9 +778,17 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
         /* skb is already created with CHECKSUM_NONE */
         skb_checksum_none_assert(skb);
 
-        /*
-         * In Linux, the IP checksum is always checked.
-         * Do L4 checksum offload if enabled and present.
+        /* Incoming packets may have IP header checksum verified by the host.
+         * They may not have IP header checksum computed after coalescing.
+         * We compute it here if the flags are set, because on Linux, the IP
+         * checksum is always checked.
+         */
+        if (csum_info && csum_info->receive.ip_checksum_value_invalid &&
+            csum_info->receive.ip_checksum_succeeded &&
+            skb->protocol == htons(ETH_P_IP))
+                netvsc_comp_ipcsum(skb);
+
+        /* Do L4 checksum offload if enabled and present.
          */
         if (csum_info && (net->features & NETIF_F_RXCSUM)) {
                 if (csum_info->receive.tcp_checksum_succeeded ||