From 13854e5a60461daee08ce99842b7f4d37553d911 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 15 Mar 2015 21:12:16 -0700 Subject: [PATCH] inet: add proper refcounting to request sock reqsk_put() is the generic function that should be used to release a refcount (and automatically call reqsk_free()) reqsk_free() might be called if refcount is known to be 0 or undefined. refcnt is set to one in inet_csk_reqsk_queue_add() As request socks are not yet in global ehash table, I added temporary debugging checks in reqsk_put() and reqsk_free() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet_connection_sock.h | 5 +++++ include/net/inet_sock.h | 5 +++++ include/net/request_sock.h | 13 +++++++------ net/core/request_sock.c | 4 ++-- net/ipv4/inet_connection_sock.c | 8 ++++---- net/ipv4/syncookies.c | 10 +++++----- net/ipv4/tcp_fastopen.c | 2 +- 7 files changed, 29 insertions(+), 18 deletions(-) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index b9a6b0a94cc6..191feec60205 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -275,6 +275,11 @@ static inline void inet_csk_reqsk_queue_add(struct sock *sk, struct sock *child) { reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child); + /* before letting lookups find us, make sure all req fields + * are committed to memory. + */ + smp_wmb(); + atomic_set(&req->rsk_refcnt, 1); } void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index b3053fdd871e..3d8c09abb097 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -255,6 +255,11 @@ static inline struct request_sock *inet_reqsk_alloc(struct request_sock_ops *ops ireq->opt = NULL; atomic64_set(&ireq->ir_cookie, 0); ireq->ireq_state = TCP_NEW_SYN_RECV; + + /* Following is temporary. It is coupled with debugging + * helpers in reqsk_put() & reqsk_free() + */ + atomic_set(&ireq->ireq_refcnt, 0); } return req; diff --git a/include/net/request_sock.h b/include/net/request_sock.h index 3275cf31f731..56dc2faba47e 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -82,19 +82,20 @@ static inline struct request_sock *inet_reqsk(struct sock *sk) return (struct request_sock *)sk; } -static inline void __reqsk_free(struct request_sock *req) -{ - kmem_cache_free(req->rsk_ops->slab, req); -} - static inline void reqsk_free(struct request_sock *req) { + /* temporary debugging */ + WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0); + req->rsk_ops->destructor(req); - __reqsk_free(req); + kmem_cache_free(req->rsk_ops->slab, req); } static inline void reqsk_put(struct request_sock *req) { + /* temporary debugging, until req sock are put into ehash table */ + WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 1); + if (atomic_dec_and_test(&req->rsk_refcnt)) reqsk_free(req); } diff --git a/net/core/request_sock.c b/net/core/request_sock.c index 04db318e6218..e910317ef6d9 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c @@ -103,7 +103,7 @@ void reqsk_queue_destroy(struct request_sock_queue *queue) while ((req = lopt->syn_table[i]) != NULL) { lopt->syn_table[i] = req->dl_next; lopt->qlen--; - reqsk_free(req); + reqsk_put(req); } } } @@ -180,7 +180,7 @@ void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, */ spin_unlock_bh(&fastopenq->lock); sock_put(lsk); - reqsk_free(req); + reqsk_put(req); return; } /* Wait for 60secs before removing a req that has triggered RST. diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 34581f928afa..3390ba6f96b2 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -340,7 +340,7 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) out: release_sock(sk); if (req) - __reqsk_free(req); + reqsk_put(req); return newsk; out_err: newsk = NULL; @@ -635,7 +635,7 @@ void inet_csk_reqsk_queue_prune(struct sock *parent, /* Drop this request */ inet_csk_reqsk_queue_unlink(parent, req, reqp); reqsk_queue_removed(queue, req); - reqsk_free(req); + reqsk_put(req); continue; } reqp = &req->dl_next; @@ -837,7 +837,7 @@ void inet_csk_listen_stop(struct sock *sk) sock_put(child); sk_acceptq_removed(sk); - __reqsk_free(req); + reqsk_put(req); } if (queue->fastopenq != NULL) { /* Free all the reqs queued in rskq_rst_head. */ @@ -847,7 +847,7 @@ void inet_csk_listen_stop(struct sock *sk) spin_unlock_bh(&queue->fastopenq->lock); while ((req = acc_req) != NULL) { acc_req = req->dl_next; - __reqsk_free(req); + reqsk_put(req); } } WARN_ON(sk->sk_ack_backlog); diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index f17db898ed26..5ae0c49f5e2e 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -219,9 +219,9 @@ int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, } EXPORT_SYMBOL_GPL(__cookie_v4_check); -static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, - struct request_sock *req, - struct dst_entry *dst) +static struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, + struct request_sock *req, + struct dst_entry *dst) { struct inet_connection_sock *icsk = inet_csk(sk); struct sock *child; @@ -357,7 +357,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) ireq->opt = tcp_v4_save_options(skb); if (security_inet_conn_request(sk, skb, req)) { - reqsk_free(req); + reqsk_put(req); goto out; } @@ -378,7 +378,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) security_req_classify_flow(req, flowi4_to_flowi(&fl4)); rt = ip_route_output_key(sock_net(sk), &fl4); if (IS_ERR(rt)) { - reqsk_free(req); + reqsk_put(req); goto out; } diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index fe77417fc137..84381319e1bc 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -253,7 +253,7 @@ static bool tcp_fastopen_queue_check(struct sock *sk) fastopenq->rskq_rst_head = req1->dl_next; fastopenq->qlen--; spin_unlock(&fastopenq->lock); - reqsk_free(req1); + reqsk_put(req1); } return true; }