net/smc: Fix loop in smc_listen

The kernel_listen function in smc_listen will fail when all the available
ports are occupied.  At this point smc->clcsock->sk->sk_data_ready has
been changed to smc_clcsock_data_ready.  When we call smc_listen again,
now both smc->clcsock->sk->sk_data_ready and smc->clcsk_data_ready point
to the smc_clcsock_data_ready function.

The smc_clcsock_data_ready() function calls lsmc->clcsk_data_ready which
now points to itself resulting in an infinite loop.

This patch restores smc->clcsock->sk->sk_data_ready with the old value.

Fixes: 8d4dc116db0e ("net/smc: reduce active tcp_listen workers")
Signed-off-by: Guo DaXing <guodaxing@huawei.com>
Acked-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 2692cba5a7b6829de3c0555050b56c606cdd77fa..4b62c925a13e88352b049041c501d45cf6bd1345 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2134,8 +2134,10 @@ static int smc_listen(struct socket *sock, int backlog)
        smc->clcsock->sk->sk_user_data =
                (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY);
        rc = kernel_listen(smc->clcsock, backlog);
-       if (rc)
+       if (rc) {
+               smc->clcsock->sk->sk_data_ready = smc->clcsk_data_ready;
                goto out;
+       }
        sk->sk_max_ack_backlog = backlog;
        sk->sk_ack_backlog = 0;
        sk->sk_state = SMC_LISTEN;