diff options
Diffstat (limited to 'net/core/stream.c')
| -rw-r--r-- | net/core/stream.c | 65 |
1 files changed, 38 insertions, 27 deletions
diff --git a/net/core/stream.c b/net/core/stream.c index e94bb02a5629..7a37e7dd2c43 100644 --- a/net/core/stream.c +++ b/net/core/stream.c @@ -23,9 +23,13 @@ /** * sk_stream_write_space - stream socket write_space callback. - * @sk: socket + * @sk: pointer to the socket structure * - * FIXME: write proper description + * This function is invoked when there's space available in the socket's + * send buffer for writing. It first checks if the socket is writable, + * clears the SOCK_NOSPACE flag indicating that memory for writing + * is now available, wakes up any processes waiting for write operations + * and sends asynchronous notifications if needed. */ void sk_stream_write_space(struct sock *sk) { @@ -73,13 +77,13 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p) add_wait_queue(sk_sleep(sk), &wait); sk->sk_write_pending++; done = sk_wait_event(sk, timeo_p, - !sk->sk_err && - !((1 << sk->sk_state) & + !READ_ONCE(sk->sk_err) && + !((1 << READ_ONCE(sk->sk_state)) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)), &wait); remove_wait_queue(sk_sleep(sk), &wait); sk->sk_write_pending--; } while (!done); - return 0; + return done < 0 ? done : 0; } EXPORT_SYMBOL(sk_stream_wait_connect); @@ -87,9 +91,9 @@ EXPORT_SYMBOL(sk_stream_wait_connect); * sk_stream_closing - Return 1 if we still have things to send in our buffers. * @sk: socket to verify */ -static inline int sk_stream_closing(struct sock *sk) +static int sk_stream_closing(const struct sock *sk) { - return (1 << sk->sk_state) & + return (1 << READ_ONCE(sk->sk_state)) & (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK); } @@ -117,14 +121,13 @@ EXPORT_SYMBOL(sk_stream_wait_close); */ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) { - int err = 0; + int ret, err = 0; long vm_wait = 0; long current_timeo = *timeo_p; - bool noblock = (*timeo_p ? false : true); DEFINE_WAIT_FUNC(wait, woken_wake_function); if (sk_stream_memory_free(sk)) - current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2; + current_timeo = vm_wait = get_random_u32_below(HZ / 5) + 2; add_wait_queue(sk_sleep(sk), &wait); @@ -133,11 +136,8 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) goto do_error; - if (!*timeo_p) { - if (noblock) - set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); - goto do_nonblock; - } + if (!*timeo_p) + goto do_eagain; if (signal_pending(current)) goto do_interrupted; sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); @@ -146,11 +146,13 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); sk->sk_write_pending++; - sk_wait_event(sk, ¤t_timeo, sk->sk_err || - (sk->sk_shutdown & SEND_SHUTDOWN) || - (sk_stream_memory_free(sk) && - !vm_wait), &wait); + ret = sk_wait_event(sk, ¤t_timeo, READ_ONCE(sk->sk_err) || + (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) || + (sk_stream_memory_free(sk) && !vm_wait), + &wait); sk->sk_write_pending--; + if (ret < 0) + goto do_error; if (vm_wait) { vm_wait -= current_timeo; @@ -163,13 +165,20 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) *timeo_p = current_timeo; } out: - remove_wait_queue(sk_sleep(sk), &wait); + if (!sock_flag(sk, SOCK_DEAD)) + remove_wait_queue(sk_sleep(sk), &wait); return err; do_error: err = -EPIPE; goto out; -do_nonblock: +do_eagain: + /* Make sure that whenever EAGAIN is returned, EPOLLOUT event can + * be generated later. + * When TCP receives ACK packets that make room, tcp_check_space() + * only calls tcp_new_space() if SOCK_NOSPACE is set. + */ + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); err = -EAGAIN; goto out; do_interrupted: @@ -193,17 +202,19 @@ void sk_stream_kill_queues(struct sock *sk) /* First the read buffer. */ __skb_queue_purge(&sk->sk_receive_queue); - /* Next, the error queue. */ - __skb_queue_purge(&sk->sk_error_queue); + /* Next, the error queue. + * We need to use queue lock, because other threads might + * add packets to the queue without socket lock being held. + */ + skb_queue_purge(&sk->sk_error_queue); /* Next, the write queue. */ - WARN_ON(!skb_queue_empty(&sk->sk_write_queue)); + WARN_ON_ONCE(!skb_queue_empty(&sk->sk_write_queue)); /* Account for returned memory. */ - sk_mem_reclaim(sk); + sk_mem_reclaim_final(sk); - WARN_ON(sk->sk_wmem_queued); - WARN_ON(sk->sk_forward_alloc); + WARN_ON_ONCE(sk->sk_wmem_queued); /* It is _impossible_ for the backlog to contain anything * when we get here. All user references to this socket |