diff --git a/include/linux/net.h b/include/linux/net.h index f514e4dd5521..0b4ac7da583a 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -34,6 +34,10 @@ struct inode; struct file; struct net; +/* Historically, SOCKWQ_ASYNC_NOSPACE & SOCKWQ_ASYNC_WAITDATA were located + * in sock->flags, but moved into sk->sk_wq->flags to be RCU protected. + * Eventually all flags will be in sk->sk_wq_flags. + */ #define SOCKWQ_ASYNC_NOSPACE 0 #define SOCKWQ_ASYNC_WAITDATA 1 #define SOCK_NOSPACE 2 @@ -89,6 +93,7 @@ struct socket_wq { /* Note: wait MUST be first field of socket_wq */ wait_queue_head_t wait; struct fasync_struct *fasync_list; + unsigned long flags; /* %SOCKWQ_ASYNC_NOSPACE, etc */ struct rcu_head rcu; } ____cacheline_aligned_in_smp; @@ -202,7 +207,7 @@ enum { SOCK_WAKE_URG, }; -int sock_wake_async(struct socket *sk, int how, int band); +int sock_wake_async(struct socket_wq *sk_wq, int how, int band); int sock_register(const struct net_proto_family *fam); void sock_unregister(int family); int __sock_create(struct net *net, int family, int type, int proto, diff --git a/include/net/sock.h b/include/net/sock.h index c155d09d8af4..0434138c5f95 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -384,8 +384,10 @@ struct sock { int sk_rcvbuf; struct sk_filter __rcu *sk_filter; - struct socket_wq __rcu *sk_wq; - + union { + struct socket_wq __rcu *sk_wq; + struct socket_wq *sk_wq_raw; + }; #ifdef CONFIG_XFRM struct xfrm_policy *sk_policy[2]; #endif @@ -2005,20 +2007,27 @@ static inline unsigned long sock_wspace(struct sock *sk) return amt; } +/* Note: + * We use sk->sk_wq_raw, from contexts knowing this + * pointer is not NULL and cannot disappear/change. + */ static inline void sk_set_bit(int nr, struct sock *sk) { - set_bit(nr, &sk->sk_socket->flags); + set_bit(nr, &sk->sk_wq_raw->flags); } static inline void sk_clear_bit(int nr, struct sock *sk) { - clear_bit(nr, &sk->sk_socket->flags); + clear_bit(nr, &sk->sk_wq_raw->flags); } -static inline void sk_wake_async(struct sock *sk, int how, int band) +static inline void sk_wake_async(const struct sock *sk, int how, int band) { - if (sock_flag(sk, SOCK_FASYNC)) - sock_wake_async(sk->sk_socket, how, band); + if (sock_flag(sk, SOCK_FASYNC)) { + rcu_read_lock(); + sock_wake_async(rcu_dereference(sk->sk_wq), how, band); + rcu_read_unlock(); + } } /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might diff --git a/net/core/stream.c b/net/core/stream.c index 43309428644d..b96f7a79e544 100644 --- a/net/core/stream.c +++ b/net/core/stream.c @@ -39,7 +39,7 @@ void sk_stream_write_space(struct sock *sk) wake_up_interruptible_poll(&wq->wait, POLLOUT | POLLWRNORM | POLLWRBAND); if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN)) - sock_wake_async(sock, SOCK_WAKE_SPACE, POLL_OUT); + sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT); rcu_read_unlock(); } } diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 2353985d689c..5e35ef34008b 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -6801,26 +6801,30 @@ no_packet: static void __sctp_write_space(struct sctp_association *asoc) { struct sock *sk = asoc->base.sk; - struct socket *sock = sk->sk_socket; - if ((sctp_wspace(asoc) > 0) && sock) { - if (waitqueue_active(&asoc->wait)) - wake_up_interruptible(&asoc->wait); + if (sctp_wspace(asoc) <= 0) + return; - if (sctp_writeable(sk)) { - wait_queue_head_t *wq = sk_sleep(sk); + if (waitqueue_active(&asoc->wait)) + wake_up_interruptible(&asoc->wait); - if (wq && waitqueue_active(wq)) - wake_up_interruptible(wq); + if (sctp_writeable(sk)) { + struct socket_wq *wq; + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (wq) { + if (waitqueue_active(&wq->wait)) + wake_up_interruptible(&wq->wait); /* Note that we try to include the Async I/O support * here by modeling from the current TCP/UDP code. * We have not tested with it yet. */ if (!(sk->sk_shutdown & SEND_SHUTDOWN)) - sock_wake_async(sock, - SOCK_WAKE_SPACE, POLL_OUT); + sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT); } + rcu_read_unlock(); } } diff --git a/net/socket.c b/net/socket.c index 16be908205fc..456fadb3d819 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1056,27 +1056,20 @@ static int sock_fasync(int fd, struct file *filp, int on) return 0; } -/* This function may be called only under socket lock or callback_lock or rcu_lock */ +/* This function may be called only under rcu_lock */ -int sock_wake_async(struct socket *sock, int how, int band) +int sock_wake_async(struct socket_wq *wq, int how, int band) { - struct socket_wq *wq; + if (!wq || !wq->fasync_list) + return -1; - if (!sock) - return -1; - rcu_read_lock(); - wq = rcu_dereference(sock->wq); - if (!wq || !wq->fasync_list) { - rcu_read_unlock(); - return -1; - } switch (how) { case SOCK_WAKE_WAITD: - if (test_bit(SOCKWQ_ASYNC_WAITDATA, &sock->flags)) + if (test_bit(SOCKWQ_ASYNC_WAITDATA, &wq->flags)) break; goto call_kill; case SOCK_WAKE_SPACE: - if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sock->flags)) + if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags)) break; /* fall through */ case SOCK_WAKE_IO: @@ -1086,7 +1079,7 @@ call_kill: case SOCK_WAKE_URG: kill_fasync(&wq->fasync_list, SIGURG, band); } - rcu_read_unlock(); + return 0; } EXPORT_SYMBOL(sock_wake_async);