Re: [PATCH v4 4/4] nvme-tcp: support IPv6 traffic class

[Sagi Grimberg <sagi@grimberg.me>]

On 18/08/2026 9:03, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
>
> Currently, nvme-tcp host only supports setting the IPv4 TOS value when a
> TOS is specified, but does not handle the IPv6 traffic class.
>
> Extend the queue socket setup to handle AF_INET6 sockets by applying the
> TOS value to both IPv4 and IPv6 sockets. For IPv6, the TOS value is set
> as the IPv6 traffic class via IPV6_TCLASS using do_sock_setsockopt().
>
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>   drivers/nvme/host/tcp.c | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
>
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 025cade370b2..5f30be04a9dd 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -1815,6 +1815,17 @@ static int nvme_tcp_sock_set_tos(struct sock *sk, int tos)
>   				  KERNEL_SOCKPTR(&tos), sizeof(tos));
>   }
>   
> +static int nvme_tcp_sock_set_tclass(struct sock *sk, int tclass)
> +{
> +#if IS_ENABLED(CONFIG_IPV6)
> +	if (sk->sk_family == AF_INET6)
> +		return do_sock_setsockopt(sk->sk_socket, false, SOL_IPV6,
> +					  IPV6_TCLASS, KERNEL_SOCKPTR(&tclass),
> +					  sizeof(tclass));
> +#endif
> +	return 0;
> +}
> +
>   static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid,
>   				key_serial_t pskid)
>   {
> @@ -1909,6 +1920,15 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid,
>   				qid, ret);
>   			goto err_sock;
>   		}
> +
> +		ret = nvme_tcp_sock_set_tclass(queue->sock->sk,
> +					       nctrl->opts->tos);

Won't it just be cleaner to add a generic ip_sock_set_tclass() that 
hides the IS_ENABLED(CONFIG_IPV6) ifdef? Why do we need to wrap all 
these generic helpers?