udpv6: Add lockless sendmsg() support
This commit adds the same functionaliy to IPv6 that
commit 903ab86d195cca295379699299c5fc10beba31c7
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: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 67a3d70..d048d46 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1177,6 +1177,7 @@
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 @@
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 @@
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 @@
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 @@
dst = NULL;
}
- if (err > 0)
- err = np->recverr ? net_xmit_errno(err) : 0;
- release_sock(sk);
out:
dst_release(dst);
fl6_sock_release(flowlabel);