On 09/02/2022 15:11, D. Wythe wrote:
> From: "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx>
>
> This patch aims to add dynamic control for SMC auto fallback, since we
Same here, we need a different wording. Maybe something like
"SMC handshake limitation".
> don't have socket option level for SMC yet, which requires we need to
> implement it at the same time.
>
> This patch does the following:
>
> - add new socket option level: SOL_SMC.
> - add new SMC socket option: SMC_AUTO_FALLBACK.
> - provide getter/setter for SMC socket options.
>
> Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
> ---
> include/linux/socket.h | 1 +
> include/uapi/linux/smc.h | 4 +++
> net/smc/af_smc.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++-
> net/smc/smc.h | 1 +
> 4 files changed, 74 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/socket.h b/include/linux/socket.h
> index 8ef26d8..6f85f5d 100644
> --- a/include/linux/socket.h
> +++ b/include/linux/socket.h
> @@ -366,6 +366,7 @@ struct ucred {
> #define SOL_XDP 283
> #define SOL_MPTCP 284
> #define SOL_MCTP 285
> +#define SOL_SMC 286
>
> /* IPX options */
> #define IPX_TYPE 1
> diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
> index 6c2874f..9f2cbf8 100644
> --- a/include/uapi/linux/smc.h
> +++ b/include/uapi/linux/smc.h
> @@ -284,4 +284,8 @@ enum {
> __SMC_NLA_SEID_TABLE_MAX,
> SMC_NLA_SEID_TABLE_MAX = __SMC_NLA_SEID_TABLE_MAX - 1
> };
> +
> +/* SMC socket options */
> +#define SMC_AUTO_FALLBACK 1 /* allow auto fallback to TCP */
One idea: SMC_LIMIT_HS ?
> +
> #endif /* _UAPI_LINUX_SMC_H */
> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
> index 8175f60..c313561 100644
> --- a/net/smc/af_smc.c
> +++ b/net/smc/af_smc.c
> @@ -2325,7 +2325,8 @@ static int smc_listen(struct socket *sock, int backlog)
>
> inet_csk(smc->clcsock->sk)->icsk_af_ops = &smc->af_ops;
>
> - tcp_sk(smc->clcsock->sk)->smc_in_limited = smc_is_in_limited;
> + if (smc->auto_fallback)
> + tcp_sk(smc->clcsock->sk)->smc_in_limited = smc_is_in_limited;
>
> rc = kernel_listen(smc->clcsock, backlog);
> if (rc) {
> @@ -2620,6 +2621,67 @@ static int smc_shutdown(struct socket *sock, int how)
> return rc ? rc : rc1;
> }
>
> +static int __smc_getsockopt(struct socket *sock, int level, int optname,
> + char __user *optval, int __user *optlen)
> +{
> + struct smc_sock *smc;
> + int val, len;
> +
> + smc = smc_sk(sock->sk);
> +
> + if (get_user(len, optlen))
> + return -EFAULT;
> +
> + len = min_t(int, len, sizeof(int));
> +
> + if (len < 0)
> + return -EINVAL;
> +
> + switch (optname) {
> + case SMC_AUTO_FALLBACK:
> + val = smc->auto_fallback;
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + if (put_user(len, optlen))
> + return -EFAULT;
> + if (copy_to_user(optval, &val, len))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int __smc_setsockopt(struct socket *sock, int level, int optname,
> + sockptr_t optval, unsigned int optlen)
> +{
> + struct sock *sk = sock->sk;
> + struct smc_sock *smc;
> + int val, rc;
> +
> + smc = smc_sk(sk);
> +
> + lock_sock(sk);
> + switch (optname) {
> + case SMC_AUTO_FALLBACK:
> + if (optlen < sizeof(int))
> + return -EINVAL;
> + if (copy_from_sockptr(&val, optval, sizeof(int)))
> + return -EFAULT;
> +
> + smc->auto_fallback = !!val;
> + rc = 0;
> + break;
> + default:
> + rc = -EOPNOTSUPP;
> + break;
> + }
> + release_sock(sk);
> +
> + return rc;
> +}
> +
> static int smc_setsockopt(struct socket *sock, int level, int optname,
> sockptr_t optval, unsigned int optlen)
> {
> @@ -2629,6 +2691,8 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
>
> if (level == SOL_TCP && optname == TCP_ULP)
> return -EOPNOTSUPP;
> + else if (level == SOL_SMC)
> + return __smc_setsockopt(sock, level, optname, optval, optlen);
>
> smc = smc_sk(sk);
>
> @@ -2711,6 +2775,9 @@ static int smc_getsockopt(struct socket *sock, int level, int optname,
> struct smc_sock *smc;
> int rc;
>
> + if (level == SOL_SMC)
> + return __smc_getsockopt(sock, level, optname, optval, optlen);
> +
> smc = smc_sk(sock->sk);
> mutex_lock(&smc->clcsock_release_lock);
> if (!smc->clcsock) {
> diff --git a/net/smc/smc.h b/net/smc/smc.h
> index 5e5e38d..a0bdf75 100644
> --- a/net/smc/smc.h
> +++ b/net/smc/smc.h
> @@ -249,6 +249,7 @@ struct smc_sock { /* smc sock container */
> struct work_struct smc_listen_work;/* prepare new accept socket */
> struct list_head accept_q; /* sockets to be accepted */
> spinlock_t accept_q_lock; /* protects accept_q */
> + bool auto_fallback; /* auto fallabck to tcp */
New variable name: limit_smc_hs ?
> bool use_fallback; /* fallback to tcp */
> int fallback_rsn; /* reason for fallback */
> u32 peer_diagnosis; /* decline reason from peer */
--
Karsten
