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Commit 193cdc4a authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'udpv6_lockless_send' 



Vladislav Yasevich says:

====================
ipv6: Add lockless UDP send path

This series introduces a lockless UDPv6 send path similar to
what Herbert Xu did for IPv4 a while ago.

There are some difference from IPv4.  IPv6 caching for flow
label is a bit different, as well as it requires another cork
cork structure that holds the IPv6 ancillary data.

Please take a look.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ba0c39cb 32dce968

include/linux/ipv6.h

+7 −5
Original line number Diff line number Diff line
@@ -125,6 +125,12 @@ struct ipv6_mc_socklist; 
struct ipv6_ac_socklist;

struct ipv6_fl_socklist;



struct inet6_cork {

	struct ipv6_txoptions *opt;

	u8 hop_limit;

	u8 tclass;

};



/**

 * struct ipv6_pinfo - ipv6 private area

 *
@@ -217,11 +223,7 @@ struct ipv6_pinfo { 
	struct ipv6_txoptions	*opt;

	struct sk_buff		*pktoptions;

	struct sk_buff		*rxpmtu;

	struct {

		struct ipv6_txoptions *opt;

		u8 hop_limit;

		u8 tclass;

	} cork;

	struct inet6_cork	cork;

};



/* WARNING: don't change the layout of the members in {raw,udp,tcp}6_sock! */

include/net/ipv6.h

+19 −0
Original line number Diff line number Diff line
@@ -788,6 +788,25 @@ int ip6_push_pending_frames(struct sock *sk); 


void ip6_flush_pending_frames(struct sock *sk);



int ip6_send_skb(struct sk_buff *skb);



struct sk_buff *__ip6_make_skb(struct sock *sk, struct sk_buff_head *queue,

			       struct inet_cork_full *cork,

			       struct inet6_cork *v6_cork);

struct sk_buff *ip6_make_skb(struct sock *sk,

			     int getfrag(void *from, char *to, int offset,

					 int len, int odd, struct sk_buff *skb),

			     void *from, int length, int transhdrlen,

			     int hlimit, int tclass, struct ipv6_txoptions *opt,

			     struct flowi6 *fl6, struct rt6_info *rt,

			     unsigned int flags, int dontfrag);



static inline struct sk_buff *ip6_finish_skb(struct sock *sk)

{

	return __ip6_make_skb(sk, &sk->sk_write_queue, &inet_sk(sk)->cork,

			      &inet6_sk(sk)->cork);

}



int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6);

struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,

				      const struct in6_addr *final_dst);

net/ipv6/ip6_output.c

+241 −119
Original line number Diff line number Diff line
@@ -1041,6 +1041,7 @@ struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, 
EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);



static inline int ip6_ufo_append_data(struct sock *sk,

			struct sk_buff_head *queue,

			int getfrag(void *from, char *to, int offset, int len,

			int odd, struct sk_buff *skb),

			void *from, int length, int hh_len, int fragheaderlen,
@@ -1056,7 +1057,7 @@ static inline int ip6_ufo_append_data(struct sock *sk, 
	 * device, so create one single skb packet containing complete

	 * udp datagram

	 */

	skb = skb_peek_tail(&sk->sk_write_queue);

	skb = skb_peek_tail(queue);

	if (skb == NULL) {

		skb = sock_alloc_send_skb(sk,

			hh_len + fragheaderlen + transhdrlen + 20,
@@ -1079,7 +1080,7 @@ static inline int ip6_ufo_append_data(struct sock *sk, 
		skb->protocol = htons(ETH_P_IPV6);

		skb->csum = 0;



		__skb_queue_tail(&sk->sk_write_queue, skb);

		__skb_queue_tail(queue, skb);

	} else if (skb_is_gso(skb)) {

		goto append;

	}
@@ -1135,72 +1136,56 @@ static void ip6_append_data_mtu(unsigned int *mtu, 
	}

}



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, int length, int transhdrlen,

	int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,

	struct rt6_info *rt, unsigned int flags, int dontfrag)

static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,

			  struct inet6_cork *v6_cork,

			  int hlimit, int tclass, struct ipv6_txoptions *opt,

			  struct rt6_info *rt, struct flowi6 *fl6)

{

	struct inet_sock *inet = inet_sk(sk);

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct inet_cork *cork;

	struct sk_buff *skb, *skb_prev = NULL;

	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;

	int exthdrlen;

	int dst_exthdrlen;

	int hh_len;

	int copy;

	int err;

	int offset = 0;

	__u8 tx_flags = 0;

	u32 tskey = 0;

	unsigned int mtu;



	if (flags&MSG_PROBE)

		return 0;

	cork = &inet->cork.base;

	if (skb_queue_empty(&sk->sk_write_queue)) {

	/*

	 * setup for corking

	 */

	if (opt) {

			if (WARN_ON(np->cork.opt))

		if (WARN_ON(v6_cork->opt))

			return -EINVAL;



			np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);

			if (unlikely(np->cork.opt == NULL))

		v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);

		if (unlikely(v6_cork->opt == NULL))

			return -ENOBUFS;



			np->cork.opt->tot_len = opt->tot_len;

			np->cork.opt->opt_flen = opt->opt_flen;

			np->cork.opt->opt_nflen = opt->opt_nflen;

		v6_cork->opt->tot_len = opt->tot_len;

		v6_cork->opt->opt_flen = opt->opt_flen;

		v6_cork->opt->opt_nflen = opt->opt_nflen;



			np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,

		v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,

						    sk->sk_allocation);

			if (opt->dst0opt && !np->cork.opt->dst0opt)

		if (opt->dst0opt && !v6_cork->opt->dst0opt)

			return -ENOBUFS;



			np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,

		v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,

						    sk->sk_allocation);

			if (opt->dst1opt && !np->cork.opt->dst1opt)

		if (opt->dst1opt && !v6_cork->opt->dst1opt)

			return -ENOBUFS;



			np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,

		v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,

						   sk->sk_allocation);

			if (opt->hopopt && !np->cork.opt->hopopt)

		if (opt->hopopt && !v6_cork->opt->hopopt)

			return -ENOBUFS;



			np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,

		v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,

						    sk->sk_allocation);

			if (opt->srcrt && !np->cork.opt->srcrt)

		if (opt->srcrt && !v6_cork->opt->srcrt)

			return -ENOBUFS;



		/* need source address above miyazawa*/

	}

	dst_hold(&rt->dst);

		cork->dst = &rt->dst;

		inet->cork.fl.u.ip6 = *fl6;

		np->cork.hop_limit = hlimit;

		np->cork.tclass = tclass;

	cork->base.dst = &rt->dst;

	cork->fl.u.ip6 = *fl6;

	v6_cork->hop_limit = hlimit;

	v6_cork->tclass = tclass;

	if (rt->dst.flags & DST_XFRM_TUNNEL)

		mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?

		      rt->dst.dev->mtu : dst_mtu(&rt->dst);
@@ -1211,23 +1196,46 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
		if (np->frag_size)

			mtu = np->frag_size;

	}

		cork->fragsize = mtu;

	cork->base.fragsize = mtu;

	if (dst_allfrag(rt->dst.path))

			cork->flags |= IPCORK_ALLFRAG;

		cork->length = 0;

		exthdrlen = (opt ? opt->opt_flen : 0);

		length += exthdrlen;

		transhdrlen += exthdrlen;

		cork->base.flags |= IPCORK_ALLFRAG;

	cork->base.length = 0;



	return 0;

}



static int __ip6_append_data(struct sock *sk,

			     struct flowi6 *fl6,

			     struct sk_buff_head *queue,

			     struct inet_cork *cork,

			     struct inet6_cork *v6_cork,

			     struct page_frag *pfrag,

			     int getfrag(void *from, char *to, int offset,

					 int len, int odd, struct sk_buff *skb),

			     void *from, int length, int transhdrlen,

			     unsigned int flags, int dontfrag)

{

	struct sk_buff *skb, *skb_prev = NULL;

	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;

	int exthdrlen = 0;

	int dst_exthdrlen = 0;

	int hh_len;

	int copy;

	int err;

	int offset = 0;

	__u8 tx_flags = 0;

	u32 tskey = 0;

	struct rt6_info *rt = (struct rt6_info *)cork->dst;

	struct ipv6_txoptions *opt = v6_cork->opt;

	int csummode = CHECKSUM_NONE;



	skb = skb_peek_tail(queue);

	if (!skb) {

		exthdrlen = opt ? opt->opt_flen : 0;

		dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;

	} else {

		rt = (struct rt6_info *)cork->dst;

		fl6 = &inet->cork.fl.u.ip6;

		opt = np->cork.opt;

		transhdrlen = 0;

		exthdrlen = 0;

		dst_exthdrlen = 0;

		mtu = cork->fragsize;

	}



	mtu = cork->fragsize;

	orig_mtu = mtu;



	hh_len = LL_RESERVED_SPACE(rt->dst.dev);
@@ -1276,6 +1284,14 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			tskey = sk->sk_tskey++;

	}



	/* If this is the first and only packet and device

	 * supports checksum offloading, let's use it.

	 */

	if (!skb &&

	    length + fragheaderlen < mtu &&

	    rt->dst.dev->features & NETIF_F_V6_CSUM &&

	    !exthdrlen)

		csummode = CHECKSUM_PARTIAL;

	/*

	 * Let's try using as much space as possible.

	 * Use MTU if total length of the message fits into the MTU.
@@ -1292,13 +1308,12 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
	 * --yoshfuji

	 */



	skb = skb_peek_tail(&sk->sk_write_queue);

	cork->length += length;

	if (((length > mtu) ||

	     (skb && skb_is_gso(skb))) &&

	    (sk->sk_protocol == IPPROTO_UDP) &&

	    (rt->dst.dev->features & NETIF_F_UFO)) {

		err = ip6_ufo_append_data(sk, getfrag, from, length,

		err = ip6_ufo_append_data(sk, queue, getfrag, from, length,

					  hh_len, fragheaderlen,

					  transhdrlen, mtu, flags, rt);

		if (err)
@@ -1389,7 +1404,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			 *	Fill in the control structures

			 */

			skb->protocol = htons(ETH_P_IPV6);

			skb->ip_summed = CHECKSUM_NONE;

			skb->ip_summed = csummode;

			skb->csum = 0;

			/* reserve for fragmentation and ipsec header */

			skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
@@ -1439,7 +1454,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			/*

			 * Put the packet on the pending queue

			 */

			__skb_queue_tail(&sk->sk_write_queue, skb);

			__skb_queue_tail(queue, skb);

			continue;

		}
@@ -1458,7 +1473,6 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			}

		} else {

			int i = skb_shinfo(skb)->nr_frags;

			struct page_frag *pfrag = sk_page_frag(sk);



			err = -ENOMEM;

			if (!sk_page_frag_refill(sk, pfrag))
@@ -1501,43 +1515,81 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
	IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);

	return err;

}



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, int length, int transhdrlen, int hlimit,

		    int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,

		    struct rt6_info *rt, unsigned int flags, int dontfrag)

{

	struct inet_sock *inet = inet_sk(sk);

	struct ipv6_pinfo *np = inet6_sk(sk);

	int exthdrlen;

	int err;



	if (flags&MSG_PROBE)

		return 0;

	if (skb_queue_empty(&sk->sk_write_queue)) {

		/*

		 * setup for corking

		 */

		err = ip6_setup_cork(sk, &inet->cork, &np->cork, hlimit,

				     tclass, opt, rt, fl6);

		if (err)

			return err;



		exthdrlen = (opt ? opt->opt_flen : 0);

		length += exthdrlen;

		transhdrlen += exthdrlen;

	} else {

		fl6 = &inet->cork.fl.u.ip6;

		transhdrlen = 0;

	}



	return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,

				 &np->cork, sk_page_frag(sk), getfrag,

				 from, length, transhdrlen, flags, dontfrag);

}

EXPORT_SYMBOL_GPL(ip6_append_data);



static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)

static void ip6_cork_release(struct inet_cork_full *cork,

			     struct inet6_cork *v6_cork)

{

	if (np->cork.opt) {

		kfree(np->cork.opt->dst0opt);

		kfree(np->cork.opt->dst1opt);

		kfree(np->cork.opt->hopopt);

		kfree(np->cork.opt->srcrt);

		kfree(np->cork.opt);

		np->cork.opt = NULL;

	if (v6_cork->opt) {

		kfree(v6_cork->opt->dst0opt);

		kfree(v6_cork->opt->dst1opt);

		kfree(v6_cork->opt->hopopt);

		kfree(v6_cork->opt->srcrt);

		kfree(v6_cork->opt);

		v6_cork->opt = NULL;

	}



	if (inet->cork.base.dst) {

		dst_release(inet->cork.base.dst);

		inet->cork.base.dst = NULL;

		inet->cork.base.flags &= ~IPCORK_ALLFRAG;

	if (cork->base.dst) {

		dst_release(cork->base.dst);

		cork->base.dst = NULL;

		cork->base.flags &= ~IPCORK_ALLFRAG;

	}

	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));

	memset(&cork->fl, 0, sizeof(cork->fl));

}



int ip6_push_pending_frames(struct sock *sk)

struct sk_buff *__ip6_make_skb(struct sock *sk,

			       struct sk_buff_head *queue,

			       struct inet_cork_full *cork,

			       struct inet6_cork *v6_cork)

{

	struct sk_buff *skb, *tmp_skb;

	struct sk_buff **tail_skb;

	struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;

	struct inet_sock *inet = inet_sk(sk);

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct net *net = sock_net(sk);

	struct ipv6hdr *hdr;

	struct ipv6_txoptions *opt = np->cork.opt;

	struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;

	struct flowi6 *fl6 = &inet->cork.fl.u.ip6;

	struct ipv6_txoptions *opt = v6_cork->opt;

	struct rt6_info *rt = (struct rt6_info *)cork->base.dst;

	struct flowi6 *fl6 = &cork->fl.u.ip6;

	unsigned char proto = fl6->flowi6_proto;

	int err = 0;



	skb = __skb_dequeue(&sk->sk_write_queue);

	skb = __skb_dequeue(queue);

	if (skb == NULL)

		goto out;

	tail_skb = &(skb_shinfo(skb)->frag_list);
@@ -1545,7 +1597,7 @@ int ip6_push_pending_frames(struct sock *sk) 
	/* move skb->data to ip header from ext header */

	if (skb->data < skb_network_header(skb))

		__skb_pull(skb, skb_network_offset(skb));

	while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {

	while ((tmp_skb = __skb_dequeue(queue)) != NULL) {

		__skb_pull(tmp_skb, skb_network_header_len(skb));

		*tail_skb = tmp_skb;

		tail_skb = &(tmp_skb->next);
@@ -1570,10 +1622,10 @@ int ip6_push_pending_frames(struct sock *sk) 
	skb_reset_network_header(skb);

	hdr = ipv6_hdr(skb);



	ip6_flow_hdr(hdr, np->cork.tclass,

	ip6_flow_hdr(hdr, v6_cork->tclass,

		     ip6_make_flowlabel(net, skb, fl6->flowlabel,

					np->autoflowlabel));

	hdr->hop_limit = np->cork.hop_limit;

	hdr->hop_limit = v6_cork->hop_limit;

	hdr->nexthdr = proto;

	hdr->saddr = fl6->saddr;

	hdr->daddr = *final_dst;
@@ -1590,34 +1642,104 @@ int ip6_push_pending_frames(struct sock *sk) 
		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);

	}



	ip6_cork_release(cork, v6_cork);

out:

	return skb;

}



int ip6_send_skb(struct sk_buff *skb)

{

	struct net *net = sock_net(skb->sk);

	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);

	int err;



	err = ip6_local_out(skb);

	if (err) {

		if (err > 0)

			err = net_xmit_errno(err);

		if (err)

			goto error;

			IP6_INC_STATS(net, rt->rt6i_idev,

				      IPSTATS_MIB_OUTDISCARDS);

	}



out:

	ip6_cork_release(inet, np);

	return err;

error:

	IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);

	goto out;

}



int ip6_push_pending_frames(struct sock *sk)

{

	struct sk_buff *skb;



	skb = ip6_finish_skb(sk);

	if (!skb)

		return 0;



	return ip6_send_skb(skb);

}

EXPORT_SYMBOL_GPL(ip6_push_pending_frames);



void ip6_flush_pending_frames(struct sock *sk)

static void __ip6_flush_pending_frames(struct sock *sk,

				       struct sk_buff_head *queue,

				       struct inet_cork_full *cork,

				       struct inet6_cork *v6_cork)

{

	struct sk_buff *skb;



	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {

	while ((skb = __skb_dequeue_tail(queue)) != NULL) {

		if (skb_dst(skb))

			IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),

				      IPSTATS_MIB_OUTDISCARDS);

		kfree_skb(skb);

	}



	ip6_cork_release(inet_sk(sk), inet6_sk(sk));

	ip6_cork_release(cork, v6_cork);

}



void ip6_flush_pending_frames(struct sock *sk)

{

	__ip6_flush_pending_frames(sk, &sk->sk_write_queue,

				   &inet_sk(sk)->cork, &inet6_sk(sk)->cork);

}

EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);



struct sk_buff *ip6_make_skb(struct sock *sk,

			     int getfrag(void *from, char *to, int offset,

					 int len, int odd, struct sk_buff *skb),

			     void *from, int length, int transhdrlen,

			     int hlimit, int tclass,

			     struct ipv6_txoptions *opt, struct flowi6 *fl6,

			     struct rt6_info *rt, unsigned int flags,

			     int dontfrag)

{

	struct inet_cork_full cork;

	struct inet6_cork v6_cork;

	struct sk_buff_head queue;

	int exthdrlen = (opt ? opt->opt_flen : 0);

	int err;



	if (flags & MSG_PROBE)

		return NULL;



	__skb_queue_head_init(&queue);



	cork.base.flags = 0;

	cork.base.addr = 0;

	cork.base.opt = NULL;

	v6_cork.opt = NULL;

	err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6);

	if (err)

		return ERR_PTR(err);



	if (dontfrag < 0)

		dontfrag = inet6_sk(sk)->dontfrag;



	err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,

				&current->task_frag, getfrag, from,

				length + exthdrlen, transhdrlen + exthdrlen,

				flags, dontfrag);

	if (err) {

		__ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);

		return ERR_PTR(err);

	}



	return __ip6_make_skb(sk, &queue, &cork, &v6_cork);

}

net/ipv6/udp.c

+60 −31
Original line number Diff line number Diff line
@@ -990,9 +990,10 @@ static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb, 
{

	unsigned int offset;

	struct udphdr *uh = udp_hdr(skb);

	struct sk_buff *frags = skb_shinfo(skb)->frag_list;

	__wsum csum = 0;



	if (skb_queue_len(&sk->sk_write_queue) == 1) {

	if (!frags) {

		/* Only one fragment on the socket.  */

		skb->csum_start = skb_transport_header(skb) - skb->head;

		skb->csum_offset = offsetof(struct udphdr, check);
@@ -1008,9 +1009,9 @@ static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb, 


		skb->ip_summed = CHECKSUM_NONE;



		skb_queue_walk(&sk->sk_write_queue, skb) {

			csum = csum_add(csum, skb->csum);

		}

		do {

			csum = csum_add(csum, frags->csum);

		} while ((frags = frags->next));



		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,

					    csum);
@@ -1023,26 +1024,15 @@ static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb, 
 *	Sending

 */



static int udp_v6_push_pending_frames(struct sock *sk)

static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)

{

	struct sk_buff *skb;

	struct sock *sk = skb->sk;

	struct udphdr *uh;

	struct udp_sock  *up = udp_sk(sk);

	struct inet_sock *inet = inet_sk(sk);

	struct flowi6 *fl6;

	int err = 0;

	int is_udplite = IS_UDPLITE(sk);

	__wsum csum = 0;



	if (up->pending == AF_INET)

		return udp_push_pending_frames(sk);



	fl6 = &inet->cork.fl.u.ip6;



	/* Grab the skbuff where UDP header space exists. */

	skb = skb_peek(&sk->sk_write_queue);

	if (skb == NULL)

		goto out;

	int offset = skb_transport_offset(skb);

	int len = skb->len - offset;



	/*

	 * Create a UDP header
@@ -1050,29 +1040,28 @@ static int udp_v6_push_pending_frames(struct sock *sk) 
	uh = udp_hdr(skb);

	uh->source = fl6->fl6_sport;

	uh->dest = fl6->fl6_dport;

	uh->len = htons(up->len);

	uh->len = htons(len);

	uh->check = 0;



	if (is_udplite)

		csum = udplite_csum_outgoing(sk, skb);

	else if (up->no_check6_tx) {   /* UDP csum disabled */

		csum = udplite_csum(skb);

	else if (udp_sk(sk)->no_check6_tx) {   /* UDP csum disabled */

		skb->ip_summed = CHECKSUM_NONE;

		goto send;

	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */

		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr,

				     up->len);

		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);

		goto send;

	} else

		csum = udp_csum_outgoing(sk, skb);

		csum = udp_csum(skb);



	/* add protocol-dependent pseudo-header */

	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,

				    up->len, fl6->flowi6_proto, csum);

				    len, fl6->flowi6_proto, csum);

	if (uh->check == 0)

		uh->check = CSUM_MANGLED_0;



send:

	err = ip6_push_pending_frames(sk);

	err = ip6_send_skb(skb);

	if (err) {

		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {

			UDP6_INC_STATS_USER(sock_net(sk),
@@ -1082,6 +1071,30 @@ static int udp_v6_push_pending_frames(struct sock *sk) 
	} else

		UDP6_INC_STATS_USER(sock_net(sk),

				    UDP_MIB_OUTDATAGRAMS, is_udplite);

	return err;

}



static int udp_v6_push_pending_frames(struct sock *sk)

{

	struct sk_buff *skb;

	struct udp_sock  *up = udp_sk(sk);

	struct flowi6 fl6;

	int err = 0;



	if (up->pending == AF_INET)

		return udp_push_pending_frames(sk);



	/* ip6_finish_skb will release the cork, so make a copy of

	 * fl6 here.

	 */

	fl6 = inet_sk(sk)->cork.fl.u.ip6;



	skb = ip6_finish_skb(sk);

	if (!skb)

		goto out;



	err = udp_v6_send_skb(skb, &fl6);



out:

	up->len = 0;

	up->pending = 0;
@@ -1164,6 +1177,7 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, 
	if (len > INT_MAX - sizeof(struct udphdr))

		return -EMSGSIZE;



	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;

	if (up->pending) {

		/*

		 * There are pending frames.
@@ -1294,6 +1308,20 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, 
		goto do_confirm;

back_from_confirm:



	/* Lockless fast path for the non-corking case */

	if (!corkreq) {

		struct sk_buff *skb;



		skb = ip6_make_skb(sk, getfrag, msg, ulen,

				   sizeof(struct udphdr), hlimit, tclass, opt,

				   &fl6, (struct rt6_info *)dst,

				   msg->msg_flags, dontfrag);

		err = PTR_ERR(skb);

		if (!IS_ERR_OR_NULL(skb))

			err = udp_v6_send_skb(skb, &fl6);

		goto release_dst;

	}



	lock_sock(sk);

	if (unlikely(up->pending)) {

		/* The socket is already corked while preparing it. */
@@ -1311,7 +1339,6 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, 
	if (dontfrag < 0)

		dontfrag = np->dontfrag;

	up->len += ulen;

	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;

	err = ip6_append_data(sk, getfrag, msg, ulen,

		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,

		(struct rt6_info *)dst,
@@ -1323,6 +1350,11 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, 
	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))

		up->pending = 0;



	if (err > 0)

		err = np->recverr ? net_xmit_errno(err) : 0;

	release_sock(sk);



release_dst:

	if (dst) {

		if (connected) {

			ip6_dst_store(sk, dst,
@@ -1339,9 +1371,6 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, 
		dst = NULL;

	}



	if (err > 0)

		err = np->recverr ? net_xmit_errno(err) : 0;

	release_sock(sk);

out:

	dst_release(dst);

	fl6_sock_release(flowlabel);