Revert "ipv6: save dontfrag in cork"

This reverts commit 29533d1a54b8de5aaf8c4aa6790dc67d5c14fba5 which is
commit a18dfa9925b9ef6107ea3aa5814ca3c704d34a8a upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I8f9a6b9c5c5ff2541cba90431bbb848a4ec98c10
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

include/linux/ipv6.h

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 97f7254f..ee9f913 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -196,7 +196,6 @@ struct inet6_cork {
 	struct ipv6_txoptions *opt;
 	u8 hop_limit;
 	u8 tclass;
-	u8 dontfrag:1;
 };
 
 /**

net/ipv6/ip6_output.c

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d0b0451..3c3a08b 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1417,7 +1417,6 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 	cork->fl.u.ip6 = *fl6;
 	v6_cork->hop_limit = ipc6->hlimit;
 	v6_cork->tclass = ipc6->tclass;
-	v6_cork->dontfrag = ipc6->dontfrag;
 	if (rt->dst.flags & DST_XFRM_TUNNEL)
 		mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
 		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
@@ -1452,7 +1451,7 @@ 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)
+			     unsigned int flags, struct ipcm6_cookie *ipc6)
 {
 	struct sk_buff *skb, *skb_prev = NULL;
 	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
@@ -1509,7 +1508,7 @@ static int __ip6_append_data(struct sock *sk,
 	if (headersize + transhdrlen > mtu)
 		goto emsgsize;
 
-	if (cork->length + length > mtu - headersize && v6_cork->dontfrag &&
+	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
 	    (sk->sk_protocol == IPPROTO_UDP ||
 	     sk->sk_protocol == IPPROTO_RAW)) {
 		ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
@@ -1827,7 +1826,7 @@ int ip6_append_data(struct sock *sk,
 
 	return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
 				 &np->cork, sk_page_frag(sk), getfrag,
-				 from, length, transhdrlen, flags);
+				 from, length, transhdrlen, flags, ipc6);
 }
 EXPORT_SYMBOL_GPL(ip6_append_data);
 
@@ -2022,7 +2021,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 	err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork,
 				&current->task_frag, getfrag, from,
 				length + exthdrlen, transhdrlen + exthdrlen,
-				flags);
+				flags, ipc6);
 	if (err) {
 		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
 		return ERR_PTR(err);