net/smc: allow fallback after clc timeouts

If connection initialization fails for the LLC CONFIRM LINK or the
LLC ADD LINK step, fallback to TCP should be enabled. Thus
the negative return code -EAGAIN should switch to a positive timeout
reason code in these cases, and the internal CLC socket should
not have a set sk_err.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index d9b1a0e4446cd0a9418f71a478ad55c0cb25442f..66836cfbc587680864561e6c33a5631de54a93f3 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -336,7 +336,7 @@ static int smc_clnt_conf_first_link(struct smc_sock *smc)
 
                rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
                                      SMC_CLC_DECLINE);
-               return rc;
+               return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_CL : rc;
        }
 
        if (link->llc_confirm_rc)
@@ -364,7 +364,7 @@ static int smc_clnt_conf_first_link(struct smc_sock *smc)
 
                rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
                                      SMC_CLC_DECLINE);
-               return rc;
+               return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_AL : rc;
        }
 
        /* send add link reject message, only one link supported for now */
@@ -966,7 +966,7 @@ static int smc_serv_conf_first_link(struct smc_sock *smc)
 
                rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
                                      SMC_CLC_DECLINE);
-               return rc;
+               return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_CL : rc;
        }
 
        if (link->llc_confirm_resp_rc)
@@ -987,7 +987,7 @@ static int smc_serv_conf_first_link(struct smc_sock *smc)
 
                rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
                                      SMC_CLC_DECLINE);
-               return rc;
+               return rc == -EAGAIN ? SMC_CLC_DECL_TIMEOUT_AL : rc;
        }
 
        smc_llc_link_active(link, net->ipv4.sysctl_tcp_keepalive_time);

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 7278ec0cfa582c75e91a63d7c2d5d559878130dc..62043d69e3a3157df543ba4841391010ccaf03e2 100644 (file)
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -297,7 +297,11 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
        }
        if (clc_sk->sk_err) {
                reason_code = -clc_sk->sk_err;
-               smc->sk.sk_err = clc_sk->sk_err;
+               if (clc_sk->sk_err == EAGAIN &&
+                   expected_type == SMC_CLC_DECLINE)
+                       clc_sk->sk_err = 0; /* reset for fallback usage */
+               else
+                       smc->sk.sk_err = clc_sk->sk_err;
                goto out;
        }
        if (!len) { /* peer has performed orderly shutdown */
@@ -306,7 +310,8 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
                goto out;
        }
        if (len < 0) {
-               smc->sk.sk_err = -len;
+               if (len != -EAGAIN || expected_type != SMC_CLC_DECLINE)
+                       smc->sk.sk_err = -len;
                reason_code = len;
                goto out;
        }