This is a note to let you know that I've just added the patch titled
net/smc: fix fallback failed while sendmsg with fastopen
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-smc-fix-fallback-failed-while-sendmsg-with-fasto.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1340c5c16e9dc4b5ab7f9d18a3223c15a97727d3
Author: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
Date: Tue Mar 7 11:23:46 2023 +0800
net/smc: fix fallback failed while sendmsg with fastopen
[ Upstream commit ce7ca794712f186da99719e8b4e97bd5ddbb04c3 ]
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: ee9dfbef02d1 ("net/smc: handle sockopts forcing fallback")
Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
Signed-off-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
v2 -> v1: Optimize code style
Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index d5ddf283ed8e2..9cdb7df0801f3 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2172,16 +2172,14 @@ static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct smc_sock *smc;
- int rc = -EPIPE;
+ int rc;
smc = smc_sk(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) {
+ /* not connected yet, fallback */
if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
rc = smc_switch_to_fallback(smc, SMC_CLC_DECL_OPTUNSUPP);
if (rc)
@@ -2190,6 +2188,11 @@ static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
rc = -EINVAL;
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) {
