Re: [PATCH v2 bpf-next 3/8] bpf: tcp: Introduce bpf_tcp_ops.{enqueue,dequeue}_rcvq().

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] bpf: multi-line comment style violation for BPF_SOCK_OPS_RCVQ_CB_FLAG
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commit 304bdb98cffa8e2d03b8207be4eaaadba075d6be
Author: Kuniyuki Iwashima <kuniyu@google.com>

bpf: tcp: Introduce bpf_tcp_ops.{enqueue,dequeue}_rcvq().

This commit introduces opt-in callbacks to bpf_tcp_ops that are invoked when
the TCP stack enqueues or dequeues data to the receive queue. These callbacks
allow a BPF program to parse each skb and dynamically adjust sk_rcvlowat to
suppress unnecessary EPOLLIN wakeups.

[ ... ]

> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 0aaa54359aebc..3f0877b5867bd 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -7148,8 +7148,17 @@ enum {
>  	 * options first before the BPF program does.
>  	 */
>  	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
> +	/* Call bpf when the TCP stack enqueues/dequeues payload
> +	 * to/from sk->sk_receive_queue.

[Severity: Low]
This isn't a bug, but does this comment violate the BPF subsystem multi-line
comment style? The BPF guidelines request that multi-line comments have the
opening /* on its own line.

> +	 *
> +	 * Only bpf_tcp_ops is supported.
> +	 *
> +	 * It can be used to adjust sk->sk_rcvlowat and suppress
> +	 * unnecessary wakeups before sufficient data is available.
> +	 */
> +	BPF_SOCK_OPS_RCVQ_CB_FLAG = (1<<7),

[ ... ]

> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 0aaa54359aebc..3f0877b5867bd 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -7148,8 +7148,17 @@ enum {
>  	 * options first before the BPF program does.
>  	 */
>  	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
> +	/* Call bpf when the TCP stack enqueues/dequeues payload
> +	 * to/from sk->sk_receive_queue.

[Severity: Low]
This isn't a bug, but this appears to be the same multi-line comment style
violation mirrored into the tools header.

> +	 *
> +	 * Only bpf_tcp_ops is supported.
> +	 *
> +	 * It can be used to adjust sk->sk_rcvlowat and suppress
> +	 * unnecessary wakeups before sufficient data is available.
> +	 */
> +	BPF_SOCK_OPS_RCVQ_CB_FLAG = (1<<7),

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260923213719.224838-1-kuniyu@google.com?part=3