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Commit 03485f2a authored by Vlad Yasevich's avatar Vlad Yasevich Committed by David S. Miller
Browse files

udpv6: Add lockless sendmsg() support 



This commit adds the same functionaliy to IPv6 that
commit 903ab86d
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Tue Mar 1 02:36:48 2011 +0000

    udp: Add lockless transmit path

added to IPv4.

UDP transmit path can now run without a socket lock,
thus allowing multiple threads to send to a single socket
more efficiently.
This is only used when corking/MSG_MORE is not used.

Signed-off-by: default avatarVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d39d938c

net/ipv6/udp.c

+20 −4
Original line number Diff line number Diff line
@@ -1177,6 +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.
@@ -1307,6 +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. */
@@ -1324,7 +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,
@@ -1336,6 +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,
@@ -1352,9 +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);