[PATCH 4.18 26/53] net/smc: fix non-blocking connect problem

Greg Kroah-Hartman
2018-10-18T17:57:20Z

From: Ursula Braun <ubraun@linux.ibm.com>

[ Upstream commit 648a5a7aed346c3b8fe7c32a835edfb0dfbf4451 ]

In state SMC_INIT smc_poll() delegates polling to the internal
CLC socket. This means, once the connect worker has finished
its kernel_connect() step, the poll wake-up may occur. This is not
intended. The wake-up should occur from the wake up call in
smc_connect_work() after __smc_connect() has finished.
Thus in state SMC_INIT this patch now calls sock_poll_wait() on the
main SMC socket.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/smc/af_smc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -612,7 +612,10 @@ static void smc_connect_work(struct work
smc->sk.sk_err = -rc;

out:
- smc->sk.sk_state_change(&smc->sk);
+ if (smc->sk.sk_err)
+ smc->sk.sk_state_change(&smc->sk);
+ else
+ smc->sk.sk_write_space(&smc->sk);
kfree(smc->connect_info);
smc->connect_info = NULL;
release_sock(&smc->sk);
@@ -1345,7 +1348,7 @@ static __poll_t smc_poll(struct file *fi
return EPOLLNVAL;

smc = smc_sk(sock->sk);
- if ((sk->sk_state == SMC_INIT) || smc->use_fallback) {
+ if (smc->use_fallback) {
/* delegate to CLC child sock */
mask = smc->clcsock->ops->poll(file, smc->clcsock, wait);
sk->sk_err = smc->clcsock->sk->sk_err;