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

["Singh, Aman Deep" <aman.deep.singh@intel.com>]

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On 1/28/2023 4:15 AM, Ferruh Yigit wrote:
> 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

Minor typo, on => one

> 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>

Acked-by: Aman Singh<aman.deep.singh@intel.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) {

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