Re: [PATCH 14/32] net/tcp: convert to ->poll_mask

From: Eric Dumazet
Date: Fri May 11 2018 - 09:13:20 EST




On 05/11/2018 04:07 AM, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> include/net/tcp.h | 4 ++--
> net/ipv4/af_inet.c | 3 ++-
> net/ipv4/tcp.c | 31 ++++++++++++++-----------------
> net/ipv6/af_inet6.c | 3 ++-
> 4 files changed, 20 insertions(+), 21 deletions(-)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 9c9b3768b350..d4d72ea9128d 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -388,8 +388,8 @@ bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst);
> void tcp_close(struct sock *sk, long timeout);
> void tcp_init_sock(struct sock *sk);
> void tcp_init_transfer(struct sock *sk, int bpf_op);
> -__poll_t tcp_poll(struct file *file, struct socket *sock,
> - struct poll_table_struct *wait);
> +struct wait_queue_head *tcp_get_poll_head(struct socket *sock, __poll_t events);
> +__poll_t tcp_poll_mask(struct socket *sock, __poll_t events);
> int tcp_getsockopt(struct sock *sk, int level, int optname,
> char __user *optval, int __user *optlen);
> int tcp_setsockopt(struct sock *sk, int level, int optname,
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index eaed0367e669..220b51347526 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -986,7 +986,8 @@ const struct proto_ops inet_stream_ops = {
> .socketpair = sock_no_socketpair,
> .accept = inet_accept,
> .getname = inet_getname,
> - .poll = tcp_poll,
> + .get_poll_head = tcp_get_poll_head,
> + .poll_mask = tcp_poll_mask,
> .ioctl = inet_ioctl,
> .listen = inet_listen,
> .shutdown = inet_shutdown,
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 9ce1c726185e..6ec0e7a13581 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -493,33 +493,30 @@ static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
> sk->sk_prot->stream_memory_read(sk) : false);
> }
>
> +struct wait_queue_head *tcp_get_poll_head(struct socket *sock, __poll_t events)
> +{
> + sock_poll_busy_loop(sock, events);
> + sock_rps_record_flow(sock->sk);

Why are you adding sock_rps_record_flow() ?



> + return sk_sleep(sock->sk);
> +}
> +EXPORT_SYMBOL(tcp_get_poll_head);
> +
> /*
> - * Wait for a TCP event.
> - *
> - * Note that we don't need to lock the socket, as the upper poll layers
> - * take care of normal races (between the test and the event) and we don't
> - * go look at any of the socket buffers directly.
> + * Socket is not locked. We are protected from async events by poll logic and
> + * correct handling of state changes made by other threads is impossible in
> + * any case.
> */
> -__poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
> +__poll_t tcp_poll_mask(struct socket *sock, __poll_t events)
> {
> - __poll_t mask;
> struct sock *sk = sock->sk;
> const struct tcp_sock *tp = tcp_sk(sk);
> + __poll_t mask = 0;
> int state;
>
> - sock_poll_wait(file, sk_sleep(sk), wait);
> -
> state = inet_sk_state_load(sk);
> if (state == TCP_LISTEN)
> return inet_csk_listen_poll(sk);
>
> - /* Socket is not locked. We are protected from async events
> - * by poll logic and correct handling of state changes
> - * made by other threads is impossible in any case.
> - */
> -
> - mask = 0;
> -
> /*
> * EPOLLHUP is certainly not done right. But poll() doesn't
> * have a notion of HUP in just one direction, and for a
> @@ -600,7 +597,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
>
> return mask;
> }
> -EXPORT_SYMBOL(tcp_poll);
> +EXPORT_SYMBOL(tcp_poll_mask);
>
> int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
> {
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index 8da0b513f188..a43d967eeca5 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -571,7 +571,8 @@ const struct proto_ops inet6_stream_ops = {
> .socketpair = sock_no_socketpair, /* a do nothing */
> .accept = inet_accept, /* ok */
> .getname = inet6_getname,
> - .poll = tcp_poll, /* ok */
> + .get_poll_head = tcp_get_poll_head,
> + .poll_mask = tcp_poll_mask, /* ok */
> .ioctl = inet6_ioctl, /* must change */
> .listen = inet_listen, /* ok */
> .shutdown = inet_shutdown, /* ok */
>