udp: no need to preserve skb->dst

__ip_options_echo() does not need anymore skb->dst, so we can
avoid explicitly preserving it for its own sake.

This is almost a revert of commit 0ddf3fb2c43d ("udp: preserve
skb->dst if required for IP options processing") plus some
lifting to fit later changes.

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

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e6276fa..38bca2c 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1176,7 +1176,11 @@ static void udp_set_dev_scratch(struct sk_buff *skb)
        scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
        scratch->is_linear = !skb_is_nonlinear(skb);
 #endif
-       if (likely(!skb->_skb_refdst))
+       /* all head states execept sp (dst, sk, nf) are always cleared by
+        * udp_rcv() and we need to preserve secpath, if present, to eventually
+        * process IP_CMSG_PASSSEC at recvmsg() time
+        */
+       if (likely(!skb_sec_path(skb)))
                scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
 }
 
@@ -1782,13 +1786,6 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
                sk_mark_napi_id_once(sk, skb);
        }
 
-       /* At recvmsg() time we may access skb->dst or skb->sp depending on
-        * the IP options and the cmsg flags, elsewhere can we clear all
-        * pending head states while they are hot in the cache
-        */
-       if (likely(IPCB(skb)->opt.optlen == 0 && !skb_sec_path(skb)))
-               skb_release_head_state(skb);
-
        rc = __udp_enqueue_schedule_skb(sk, skb);
        if (rc < 0) {
                int is_udplite = IS_UDPLITE(sk);