From a1a5344ddbe8fd3e080013b317ac9a664490cfdf Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 4 Oct 2015 21:08:11 -0700 Subject: 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 Signed-off-by: David S. Miller --- include/net/inet_sock.h | 3 ++- include/net/request_sock.h | 11 ++++++++--- net/dccp/ipv4.c | 2 +- net/dccp/ipv6.c | 2 +- net/ipv4/syncookies.c | 2 +- net/ipv4/tcp_input.c | 8 +++++--- net/ipv6/syncookies.c | 2 +- 7 files changed, 19 insertions(+), 11 deletions(-) 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; -- cgit v1.2.3-59-g8ed1b