From: Jakub Sitnicki <jakub@cloudflare.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: daniel@iogearbox.net, lmb@isovalent.com, edumazet@google.com,
bpf@vger.kernel.org, netdev@vger.kernel.org, ast@kernel.org,
andrii@kernel.org, will@isovalent.com
Subject: Re: [PATCH bpf v6 06/12] bpf: sockmap, wake up polling after data copy
Date: Thu, 13 Apr 2023 15:00:02 +0200 [thread overview]
Message-ID: <87cz48gcdq.fsf@cloudflare.com> (raw)
In-Reply-To: <20230407171654.107311-7-john.fastabend@gmail.com>
On Fri, Apr 07, 2023 at 10:16 AM -07, John Fastabend wrote:
> 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 <john.fastabend@gmail.com>
> ---
One observation. On the happy path, we will be hitting the recently
introduced sk_data_ready tracepoint [1] twice. However, we have the
caller IP there, so we can differentiate.
[1] 40e0b0908142 ("net/sock: Introduce trace_sk_data_ready()")
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
next prev parent reply other threads:[~2023-04-13 13:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-07 17:16 [PATCH bpf v6 00/12] bpf sockmap fixes John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 01/12] bpf: sockmap, pass skb ownership through read_skb John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 02/12] bpf: sockmap, convert schedule_work into delayed_work John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 03/12] bpf: sockmap, improved check for empty queue John Fastabend
2023-04-11 17:53 ` Jakub Sitnicki
2023-04-13 17:51 ` Alexei Starovoitov
2023-04-13 20:06 ` John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 04/12] bpf: sockmap, handle fin correctly John Fastabend
2023-04-11 18:02 ` Jakub Sitnicki
2023-04-07 17:16 ` [PATCH bpf v6 05/12] bpf: sockmap, TCP data stall on recv before accept John Fastabend
2023-04-12 10:26 ` Jakub Sitnicki
2023-04-07 17:16 ` [PATCH bpf v6 06/12] bpf: sockmap, wake up polling after data copy John Fastabend
2023-04-13 13:00 ` Jakub Sitnicki [this message]
2023-04-07 17:16 ` [PATCH bpf v6 07/12] bpf: sockmap, incorrectly handling copied_seq John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 08/12] bpf: sockmap, pull socket helpers out of listen test for general use John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 09/12] bpf: sockmap, build helper to create connected socket pair John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 10/12] bpf: sockmap, test shutdown() correctly exits epoll and recv()=0 John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 11/12] bpf: sockmap, test FIONREAD returns correct bytes in rx buffer John Fastabend
2023-04-07 17:16 ` [PATCH bpf v6 12/12] bpf: sockmap, test FIONREAD returns correct bytes in rx buffer with drops John Fastabend
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