From fff1f3001cc58b5064a0f1154a7ac09b76f29c44 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 2 Oct 2015 11:43:23 -0700 Subject: [PATCH] tcp: add a spinlock to protect struct request_sock_queue struct request_sock_queue fields are currently protected by the listener 'lock' (not a real spinlock) We need to add a private spinlock instead, so that softirq handlers creating children do not have to worry with backlog notion that the listener 'lock' carries. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/request_sock.h | 37 ++++++++++++++++----------------- net/core/request_sock.c | 1 + net/ipv4/inet_connection_sock.c | 21 +++++++------------ 3 files changed, 26 insertions(+), 33 deletions(-) diff --git a/include/net/request_sock.h b/include/net/request_sock.h index d2544de329bd..202e36163ae3 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -176,9 +176,11 @@ struct fastopen_queue { * */ struct request_sock_queue { + spinlock_t rskq_lock; + u8 rskq_defer_accept; + struct request_sock *rskq_accept_head; struct request_sock *rskq_accept_tail; - u8 rskq_defer_accept; struct listen_sock *listen_opt; struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine * if TFO is enabled. @@ -196,16 +198,7 @@ void reqsk_queue_destroy(struct request_sock_queue *queue); void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, bool reset); -static inline struct request_sock * - reqsk_queue_yank_acceptq(struct request_sock_queue *queue) -{ - struct request_sock *req = queue->rskq_accept_head; - - queue->rskq_accept_head = NULL; - return req; -} - -static inline int reqsk_queue_empty(struct request_sock_queue *queue) +static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) { return queue->rskq_accept_head == NULL; } @@ -215,6 +208,7 @@ static inline void reqsk_queue_add(struct request_sock_queue *queue, struct sock *parent, struct sock *child) { + spin_lock(&queue->rskq_lock); req->sk = child; sk_acceptq_added(parent); @@ -225,18 +219,23 @@ static inline void reqsk_queue_add(struct request_sock_queue *queue, queue->rskq_accept_tail = req; req->dl_next = NULL; + spin_unlock(&queue->rskq_lock); } -static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) +static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, + struct sock *parent) { - struct request_sock *req = queue->rskq_accept_head; - - WARN_ON(req == NULL); - - queue->rskq_accept_head = req->dl_next; - if (queue->rskq_accept_head == NULL) - queue->rskq_accept_tail = NULL; + struct request_sock *req; + spin_lock_bh(&queue->rskq_lock); + req = queue->rskq_accept_head; + if (req) { + sk_acceptq_removed(parent); + queue->rskq_accept_head = req->dl_next; + if (queue->rskq_accept_head == NULL) + queue->rskq_accept_tail = NULL; + } + spin_unlock_bh(&queue->rskq_lock); return req; } diff --git a/net/core/request_sock.c b/net/core/request_sock.c index e22cfa4ed25f..8d9fd31d3d06 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c @@ -58,6 +58,7 @@ int reqsk_queue_alloc(struct request_sock_queue *queue, return -ENOMEM; get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd)); + spin_lock_init(&queue->rskq_lock); spin_lock_init(&queue->syn_wait_lock); spin_lock_init(&queue->fastopenq.lock); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index e1527882a578..0085612b9e49 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -330,10 +330,9 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) if (error) goto out_err; } - req = reqsk_queue_remove(queue); + req = reqsk_queue_remove(queue, sk); newsk = req->sk; - sk_acceptq_removed(sk); if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { spin_lock_bh(&queue->fastopenq.lock); @@ -832,11 +831,7 @@ void inet_csk_listen_stop(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); struct request_sock_queue *queue = &icsk->icsk_accept_queue; - struct request_sock *acc_req; - struct request_sock *req; - - /* make all the listen_opt local to us */ - acc_req = reqsk_queue_yank_acceptq(queue); + struct request_sock *next, *req; /* Following specs, it would be better either to send FIN * (and enter FIN-WAIT-1, it is normal close) @@ -848,11 +843,9 @@ void inet_csk_listen_stop(struct sock *sk) */ reqsk_queue_destroy(queue); - while ((req = acc_req) != NULL) { + while ((req = reqsk_queue_remove(queue, sk)) != NULL) { struct sock *child = req->sk; - acc_req = req->dl_next; - local_bh_disable(); bh_lock_sock(child); WARN_ON(sock_owned_by_user(child)); @@ -882,18 +875,18 @@ void inet_csk_listen_stop(struct sock *sk) local_bh_enable(); sock_put(child); - sk_acceptq_removed(sk); reqsk_put(req); } if (queue->fastopenq.rskq_rst_head) { /* Free all the reqs queued in rskq_rst_head. */ spin_lock_bh(&queue->fastopenq.lock); - acc_req = queue->fastopenq.rskq_rst_head; + req = queue->fastopenq.rskq_rst_head; queue->fastopenq.rskq_rst_head = NULL; spin_unlock_bh(&queue->fastopenq.lock); - while ((req = acc_req) != NULL) { - acc_req = req->dl_next; + while (req != NULL) { + next = req->dl_next; reqsk_put(req); + req = next; } } WARN_ON(sk->sk_ack_backlog); -- 2.39.5