net/smc: return ETIMEDOUT when smc_connect_clc() timeout

When smc_connect_clc() times out, it will return -EAGAIN(tcp_recvmsg
retuns -EAGAIN while timeout), then this value will passed to the
application, which is quite confusing to the applications, makes
inconsistency with TCP.

From the manual of connect, ETIMEDOUT is more suitable, and this patch
try convert EAGAIN to ETIMEDOUT in that case.
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Karsten Graul <kgraul@linux.ibm.com>
Link: https://lore.kernel.org/r/1644913490-21594-1-git-send-email-alibuda@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/smc/af_smc.c

@@ -1372,8 +1372,14 @@ static int __smc_connect(struct smc_sock *smc)
 
 	/* perform CLC handshake */
 	rc = smc_connect_clc(smc, aclc2, ini);
-	if (rc)
+	if (rc) {
+		/* -EAGAIN on timeout, see tcp_recvmsg() */
+		if (rc == -EAGAIN) {
+			rc = -ETIMEDOUT;
+			smc->sk.sk_err = ETIMEDOUT;
+		}
 		goto vlan_cleanup;
+	}
 
 	/* check if smc modes and versions of CLC proposal and accept match */
 	rc = smc_connect_check_aclc(ini, aclc);