Revert "ipv6: save dontfrag in cork"

This reverts commit 8ebf2709fe4dcd0a1b7b95bf61e529ddcd3cdf51 which is
commit a18dfa9 upstream.

A regression was introduced when backporting this to the stable kernels
without applying previous commits in this series.

When sending IPv6 UDP packets larger than MTU, EMSGSIZE was returned
instead of fragmenting the packets as expected.

As there is no compelling reason for this commit to be present in the
stable kernels it should be reverted.

Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit c46358d0275953b27c3d86f7a224e229f2d57d05)

Author: brettsheffield

include/linux/ipv6.h

@@ -205,7 +205,6 @@ struct inet6_cork {
 	struct ipv6_txoptions *opt;
 	u8 hop_limit;
 	u8 tclass;
-	u8 dontfrag:1;
 };
 
 /* struct ipv6_pinfo - ipv6 private area */

net/ipv6/ip6_output.c

@@ -1452,7 +1452,6 @@ 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 = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
 		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
@@ -1486,7 +1485,7 @@ 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;
 	struct inet_cork *cork = &cork_full->base;
@@ -1542,7 +1541,7 @@ 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_ICMPV6 ||
 	     sk->sk_protocol == IPPROTO_RAW)) {
@@ -1914,7 +1913,7 @@ 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);
+				 from, length, transhdrlen, flags, ipc6);
 }
 EXPORT_SYMBOL_GPL(ip6_append_data);
 
@@ -2119,7 +2118,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 	err = __ip6_append_data(sk, &queue, cork, &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);