From: Eric Dumazet <edumazet@google.com>
Date: Mon, 5 Oct 2015 04:08:11 +0000 (-0700)
Subject: tcp: avoid two atomic ops for syncookies
X-Git-Tag: firefly_0821_release~176^2~818^2~230^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a1a5344ddbe8fd3e080013b317ac9a664490cfdf;p=firefly-linux-kernel-4.4.55.git
tcp: avoid two atomic ops for syncookies
inet_reqsk_alloc() is used to allocate a temporary request
in order to generate a SYNACK with a cookie. Then later,
syncookie validation also uses a temporary request.
These paths already took a reference on listener refcount,
we can avoid a couple of atomic operations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 47eb67b08abd..f5bf7310e334 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -245,7 +245,8 @@ static inline unsigned int __inet_ehashfn(const __be32 laddr,
}
struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
- struct sock *sk_listener);
+ struct sock *sk_listener,
+ bool attach_listener);
static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
{
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index f83669460d82..95ab5d7aab96 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -80,7 +80,8 @@ static inline struct sock *req_to_sk(struct request_sock *req)
}
static inline struct request_sock *
-reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener)
+reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
+ bool attach_listener)
{
struct request_sock *req;
@@ -88,8 +89,12 @@ reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener)
if (req) {
req->rsk_ops = ops;
- sock_hold(sk_listener);
- req->rsk_listener = sk_listener;
+ if (attach_listener) {
+ sock_hold(sk_listener);
+ req->rsk_listener = sk_listener;
+ } else {
+ req->rsk_listener = NULL;
+ }
req_to_sk(req)->sk_prot = sk_listener->sk_prot;
sk_node_init(&req_to_sk(req)->sk_node);
sk_tx_queue_clear(req_to_sk(req));
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 8910c9567719..8e99681c8189 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -595,7 +595,7 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
goto drop;
- req = inet_reqsk_alloc(&dccp_request_sock_ops, sk);
+ req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true);
if (req == NULL)
goto drop;
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 1361a3f45df7..aed314f8c7c6 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -319,7 +319,7 @@ static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
goto drop;
- req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk);
+ req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
if (req == NULL)
goto drop;
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 729ceb5f63c6..8113c30ccf96 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -326,7 +326,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
goto out;
ret = NULL;
- req = inet_reqsk_alloc(&tcp_request_sock_ops, sk); /* for safety */
+ req = inet_reqsk_alloc(&tcp_request_sock_ops, sk, false); /* for safety */
if (!req)
goto out;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a95c8eb04ff7..ddadb318e850 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6042,9 +6042,11 @@ static void tcp_openreq_init(struct request_sock *req,
}
struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
- struct sock *sk_listener)
+ struct sock *sk_listener,
+ bool attach_listener)
{
- struct request_sock *req = reqsk_alloc(ops, sk_listener);
+ struct request_sock *req = reqsk_alloc(ops, sk_listener,
+ attach_listener);
if (req) {
struct inet_request_sock *ireq = inet_rsk(req);
@@ -6143,7 +6145,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
goto drop;
}
- req = inet_reqsk_alloc(rsk_ops, sk);
+ req = inet_reqsk_alloc(rsk_ops, sk, !want_cookie);
if (!req)
goto drop;
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 7606eba83e7b..f610b5310b17 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -170,7 +170,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
goto out;
ret = NULL;
- req = inet_reqsk_alloc(&tcp6_request_sock_ops, sk);
+ req = inet_reqsk_alloc(&tcp6_request_sock_ops, sk, false);
if (!req)
goto out;