Re: [tipc-discussion] [net] tipc: fix sleeping in tipc accept routine

[Jon M. <jm...@re...>]

On 21/07/2021 05:13, Hoang Le wrote:
> The release_sock() is blocking function, it would change the state
> after sleeping. In order to evaluate the stated condition outside
> the socket lock context, switch to use wait_woken() instead.
> 
> Signed-off-by: Hoang Le <hoa...@de...>
> ---
>   net/tipc/socket.c | 9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index 9b0b311c7ec1..2c71828b7e5c 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -2664,7 +2664,7 @@ static int tipc_listen(struct socket *sock, int len)
>   static int tipc_wait_for_accept(struct socket *sock, long timeo)
>   {
>   	struct sock *sk = sock->sk;
> -	DEFINE_WAIT(wait);
> +	DEFINE_WAIT_FUNC(wait, woken_wake_function);
>   	int err;
>   
>   	/* True wake-one mechanism for incoming connections: only
> @@ -2673,12 +2673,12 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
>   	 * anymore, the common case will execute the loop only once.
>   	*/
>   	for (;;) {
> -		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
> -					  TASK_INTERRUPTIBLE);
>   		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
> +			add_wait_queue(sk_sleep(sk), &wait);
>   			release_sock(sk);
> -			timeo = schedule_timeout(timeo);
> +			timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
>   			lock_sock(sk);
> +			remove_wait_queue(sk_sleep(sk), &wait);
>   		}
>   		err = 0;
>   		if (!skb_queue_empty(&sk->sk_receive_queue))
> @@ -2690,7 +2690,6 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
>   		if (signal_pending(current))
>   			break;
>   	}
> -	finish_wait(sk_sleep(sk), &wait);
>   	return err;
>   }
>   
> 
Acked-by: Jon Maloy <jm...@re...>