Commit d8ea07c7 authored Mar 07, 2023 by D. Wythe Committed by sanglipeng Oct 11, 2023

net/smc: fix fallback failed while sendmsg with fastopen

stable inclusion
from stable-v5.10.175
commit e1b8342a85289d0d3411744c4fc1e0fc46fc9d5c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8711T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e1b8342a85289d0d3411744c4fc1e0fc46fc9d5c



--------------------------------

[ Upstream commit ce7ca794 ]

Before determining whether the msg has unsupported options, it has been
prematurely terminated by the wrong status check.

For the application, the general usages of MSG_FASTOPEN likes

fd = socket(...)
/* rather than connect */
sendto(fd, data, len, MSG_FASTOPEN)

Hence, We need to check the flag before state check, because the sock
state here is always SMC_INIT when applications tries MSG_FASTOPEN.
Once we found unsupported options, fallback it to TCP.

Fixes: ee9dfbef ("net/smc: handle sockopts forcing fallback")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>

v2 -> v1: Optimize code style
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>

parent 339d423a

net/smc/af_smc.c

+8 −5

Original line number	Original line	Diff line number	Diff line
	@@ -1988,16 +1988,14 @@ static int smc_sendmsg(struct socket sock, struct msghdr msg, size_t len)
	{		{
	struct sock *sk = sock->sk;		struct sock *sk = sock->sk;
	struct smc_sock *smc;		struct smc_sock *smc;
	int rc = -EPIPE;		int rc;

	smc = smc_sk(sk);		smc = smc_sk(sk);
	lock_sock(sk);		lock_sock(sk);
	if ((sk->sk_state != SMC_ACTIVE) &&
	(sk->sk_state != SMC_APPCLOSEWAIT1) &&
	(sk->sk_state != SMC_INIT))
	goto out;

			/* SMC does not support connect with fastopen */
	if (msg->msg_flags & MSG_FASTOPEN) {		if (msg->msg_flags & MSG_FASTOPEN) {
			/* not connected yet, fallback */
	if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {		if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
	smc_switch_to_fallback(smc);		smc_switch_to_fallback(smc);
	smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;		smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
	@@ -2005,6 +2003,11 @@ static int smc_sendmsg(struct socket sock, struct msghdr msg, size_t len)
	rc = -EINVAL;		rc = -EINVAL;
	goto out;		goto out;
	}		}
			} else if ((sk->sk_state != SMC_ACTIVE) &&
			(sk->sk_state != SMC_APPCLOSEWAIT1) &&
			(sk->sk_state != SMC_INIT)) {
			rc = -EPIPE;
			goto out;
	}		}

	if (smc->use_fallback)		if (smc->use_fallback)