[PATCH] app/testpmd: fix link check condition on port start

[Ferruh Yigit <ferruh.yigit@amd.com>]

In testpmd port start function, 'need_check_link_status' variable is
used to detect if a link check is required after port is started.

Intention is if at least one port is started, link check should be
called, and initially 'need_check_link_status' used as following:
```
start_port
	need_check_link_status <- 0
	for each p in port
		ret <- config & start p
		if ret is failure
			break
		need_check_link_status <- 1
	if need_check_link_status
		check link
	else
		log failure message
```

Later above logic is modified [1] because when there is no port at all,
'need_check_link_status' remains zero and it causes and error message
although this is a valid use case.

For this code updated as following:

```
start_port
	need_check_link_status <- -1
	for each p in port
		need_check_link_status <- 0
		ret <- config & start p
		if ret is failure
			break
		need_check_link_status <- 1
	if need_check_link_status == 1
		check link
	else if need_check_link_status == 0
		log failure message
```

This modification works fine if 'start_port()' called for a single port,
but function support both single port and all ports with 'RTE_PORT_ALL'
parameter to the function.

When it is called for all ports, above logic is wrong because
'need_check_link_status' value reset on each iteration of the loop.

For multi port case, if last port fails to start,
'need_check_link_status' will be zero and no link check will be done and
it will log a wrong error message.

Overall there are three cases to cover:
* No port exist at all
* All ports are already started
* At least on port started successfully

To cover all three cases, one option is to use 'need_check_link_status'
have multiple values to reflect above cases.
But meaning of values are not obvious which can lead more issues in the
future.

Instead converting 'need_check_link_status' to multiple boolean
variables whose names are self explanatory.

This fixes issue and link check called if at least one port started
successfully as intended.
Also log message only printed when at least one port exists and all
ports are already in started state.

[1]
Fixes: 92d2703e2c43 ("app/testpmd: fix log with no bound device")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@amd.com>
---

Cc: michael.qiu@intel.com
---
 app/test-pmd/testpmd.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 134d79a55547..2a1125c9fe81 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2880,7 +2880,7 @@ update_bonding_port_dev_conf(portid_t bond_pid)
 int
 start_port(portid_t pid)
 {
-	int diag, need_check_link_status = -1;
+	int diag;
 	portid_t pi;
 	portid_t p_pi = RTE_MAX_ETHPORTS;
 	portid_t pl[RTE_MAX_ETHPORTS];
@@ -2891,6 +2891,9 @@ start_port(portid_t pid)
 	queueid_t qi;
 	struct rte_port *port;
 	struct rte_eth_hairpin_cap cap;
+	bool at_least_one_port_exist = false;
+	bool all_ports_already_started = true;
+	bool at_least_one_port_successfully_started = false;
 
 	if (port_id_is_invalid(pid, ENABLED_WARN))
 		return 0;
@@ -2906,11 +2909,13 @@ start_port(portid_t pid)
 			continue;
 		}
 
-		need_check_link_status = 0;
+		at_least_one_port_exist = true;
+
 		port = &ports[pi];
-		if (port->port_status == RTE_PORT_STOPPED)
+		if (port->port_status == RTE_PORT_STOPPED) {
 			port->port_status = RTE_PORT_HANDLING;
-		else {
+			all_ports_already_started = false;
+		} else {
 			fprintf(stderr, "Port %d is now not stopped\n", pi);
 			continue;
 		}
@@ -3130,15 +3135,14 @@ start_port(portid_t pid)
 			printf("Port %d: " RTE_ETHER_ADDR_PRT_FMT "\n", pi,
 					RTE_ETHER_ADDR_BYTES(&port->eth_addr));
 
-		/* at least one port started, need checking link status */
-		need_check_link_status = 1;
+		at_least_one_port_successfully_started = true;
 
 		pl[cfg_pi++] = pi;
 	}
 
-	if (need_check_link_status == 1 && !no_link_check)
+	if (at_least_one_port_successfully_started && !no_link_check)
 		check_all_ports_link_status(RTE_PORT_ALL);
-	else if (need_check_link_status == 0)
+	else if (at_least_one_port_exist & all_ports_already_started)
 		fprintf(stderr, "Please stop the ports first\n");
 
 	if (hairpin_mode & 0xf) {
-- 
2.25.1