net: Use skb_checksum_start_offset()

Replace skb->csum_start - skb_headroom(skb) with skb_checksum_start_offset().

Note for usb/smsc95xx: skb->data - skb->head == skb_headroom(skb).

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e79efaf06389..91cb1d71f018 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1650,8 +1650,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
 
                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
                         vnet_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
-                        vnet_hdr.csum_start = skb->csum_start -
-                                                        skb_headroom(skb);
+                        vnet_hdr.csum_start = skb_checksum_start_offset(skb);
                         vnet_hdr.csum_offset = skb->csum_offset;
                 } /* else everything is zero */