datapath: don't call pad_packet if not necessary

Upstream commit:
    commit 61ca533c0e94104c35fcb7858a23ec9a05d78143
    Author: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Date:   Thu Nov 14 23:51:08 2019 +0800

    net: openvswitch: don't call pad_packet if not necessary

    The nla_put_u16/nla_put_u32 makes sure that
    *attrlen is align. The call tree is that:

    nla_put_u16/nla_put_u32
      -> nla_put		attrlen = sizeof(u16) or sizeof(u32)
      -> __nla_put		attrlen
      -> __nla_reserve	attrlen
      -> skb_put(skb, nla_total_size(attrlen))

    nla_total_size returns the total length of attribute
    including padding.

    Cc: Joe Stringer <joe@ovn.org>
    Cc: William Tu <u9012063@gmail.com>
    Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Acked-by: Pravin B Shelar <pshelar@ovn.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 22a08baa3b8bde36f4be308967e3f509411f33f5..ddc0b449185171e4453f84bde3165de10b3342d0 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -512,23 +512,17 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
        }
 
        /* Add OVS_PACKET_ATTR_MRU */
-       if (upcall_info->mru) {
-               if (nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU,
-                               upcall_info->mru)) {
-                       err = -ENOBUFS;
-                       goto out;
-               }
-               pad_packet(dp, user_skb);
+       if (upcall_info->mru &&
+           nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU, upcall_info->mru)) {
+               err = -ENOBUFS;
+               goto out;
        }
 
        /* Add OVS_PACKET_ATTR_LEN when packet is truncated */
-       if (cutlen > 0) {
-               if (nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN,
-                               skb->len)) {
-                       err = -ENOBUFS;
-                       goto out;
-               }
-               pad_packet(dp, user_skb);
+       if (cutlen > 0 &&
+           nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, skb->len)) {
+               err = -ENOBUFS;
+               goto out;
        }
 
        /* Add OVS_PACKET_ATTR_HASH */