Merge branch 'follow-up-on-deduplicate-cookie-logic'

Willem de Bruijn says:

====================
follow-up on deduplicate cookie logic

1/3: I came across a leftover from cookie deduplication, due to UDP
having two code paths: lockless fast path and locked cork path.

3/3: Even though the leftover was in the fast path, this prompted me
to complete coverage to the cork path.

2/3: That uncovered a subtle API inconsistency in how dontfrag is
configured. It should not be possible to switch DF mid datagram.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

1 files changed, 5 insertions, 6 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d577bf2f3053..581bc6289081 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1386,6 +1386,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 	}
 	v6_cork->hop_limit = ipc6->hlimit;
 	v6_cork->tclass = ipc6->tclass;
+	v6_cork->dontfrag = ipc6->dontfrag;
 	if (rt->dst.flags & DST_XFRM_TUNNEL)
 		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
 		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
@@ -1421,7 +1422,7 @@ static int __ip6_append_data(struct sock *sk,
 			     int getfrag(void *from, char *to, int offset,
 					 int len, int odd, struct sk_buff *skb),
 			     void *from, size_t length, int transhdrlen,
-			     unsigned int flags, struct ipcm6_cookie *ipc6)
+			     unsigned int flags)
 {
 	struct sk_buff *skb, *skb_prev = NULL;
 	struct inet_cork *cork = &cork_full->base;
@@ -1475,7 +1476,7 @@ static int __ip6_append_data(struct sock *sk,
 	if (headersize + transhdrlen > mtu)
 		goto emsgsize;
 
-	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
+	if (cork->length + length > mtu - headersize && v6_cork->dontfrag &&
 	    (sk->sk_protocol == IPPROTO_UDP ||
 	     sk->sk_protocol == IPPROTO_ICMPV6 ||
 	     sk->sk_protocol == IPPROTO_RAW)) {
@@ -1855,7 +1856,7 @@ int ip6_append_data(struct sock *sk,
 
 	return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,
 				 &np->cork, sk_page_frag(sk), getfrag,
-				 from, length, transhdrlen, flags, ipc6);
+				 from, length, transhdrlen, flags);
 }
 EXPORT_SYMBOL_GPL(ip6_append_data);
 
@@ -2054,13 +2055,11 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 		ip6_cork_release(cork, &v6_cork);
 		return ERR_PTR(err);
 	}
-	if (ipc6->dontfrag < 0)
-		ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk);
 
 	err = __ip6_append_data(sk, &queue, cork, &v6_cork,
 				&current->task_frag, getfrag, from,
 				length + exthdrlen, transhdrlen + exthdrlen,
-				flags, ipc6);
+				flags);
 	if (err) {
 		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
 		return ERR_PTR(err);