ipv6: udp: leverage scratch area helpers

The commit b65ac44674dd ("udp: try to avoid 2 cache miss on dequeue")
leveraged the scratched area helpers for UDP v4 but I forgot to
update accordingly the IPv6 code path.

This change extends the scratch area usage to the IPv6 code, synching
the two implementations and giving some performance benefit.
IPv6 is again almost on the same level of IPv4, performance-wide.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index d1d72880572938ad99a4779f4216ccb4f14a8f92..450829dd6384fb250d6caf4840092c189f5b9715 100644 (file)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -362,7 +362,7 @@ try_again:
        if (!skb)
                return err;
 
-       ulen = skb->len;
+       ulen = udp_skb_len(skb);
        copied = len;
        if (copied > ulen - off)
                copied = ulen - off;
@@ -379,14 +379,18 @@ try_again:
 
        if (copied < ulen || peeking ||
            (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
-               checksum_valid = !udp_lib_checksum_complete(skb);
+               checksum_valid = udp_skb_csum_unnecessary(skb) ||
+                               !__udp_lib_checksum_complete(skb);
                if (!checksum_valid)
                        goto csum_copy_err;
        }
 
-       if (checksum_valid || skb_csum_unnecessary(skb))
-               err = skb_copy_datagram_msg(skb, off, msg, copied);
-       else {
+       if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
+               if (udp_skb_is_linear(skb))
+                       err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
+               else
+                       err = skb_copy_datagram_msg(skb, off, msg, copied);
+       } else {
                err = skb_copy_and_csum_datagram_msg(skb, off, msg);
                if (err == -EINVAL)
                        goto csum_copy_err;