From: John Fastabend Date: Tue, 23 May 2023 02:56:11 +0000 (-0700) Subject: bpf, sockmap: Wake up polling after data copy X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6df7f764cd3cf5a03a4a47b23be47e57e41fcd85;p=linux.git bpf, sockmap: Wake up polling after data copy When TCP stack has data ready to read sk_data_ready() is called. Sockmap overwrites this with its own handler to call into BPF verdict program. But, the original TCP socket had sock_def_readable that would additionally wake up any user space waiters with sk_wake_async(). Sockmap saved the callback when the socket was created so call the saved data ready callback and then we can wake up any epoll() logic waiting on the read. Note we call on 'copied >= 0' to account for returning 0 when a FIN is received because we need to wake up user for this as well so they can do the recvmsg() -> 0 and detect the shutdown. Fixes: 04919bed948dc ("tcp: Introduce tcp_read_skb()") Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/20230523025618.113937-8-john.fastabend@gmail.com --- diff --git a/net/core/skmsg.c b/net/core/skmsg.c index bcd45a99a3db3..08be5f409fb89 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -1199,12 +1199,21 @@ out: static void sk_psock_verdict_data_ready(struct sock *sk) { struct socket *sock = sk->sk_socket; + int copied; trace_sk_data_ready(sk); if (unlikely(!sock || !sock->ops || !sock->ops->read_skb)) return; - sock->ops->read_skb(sk, sk_psock_verdict_recv); + copied = sock->ops->read_skb(sk, sk_psock_verdict_recv); + if (copied >= 0) { + struct sk_psock *psock; + + rcu_read_lock(); + psock = sk_psock(sk); + psock->saved_data_ready(sk); + rcu_read_unlock(); + } } void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)