[dpdk-dev] [PATCH 19/20] app/testpmd: reset port status on close notification

[Ferruh Yigit]

On 9/23/2020 9:32 PM, Thomas Monjalon wrote:
> 23/09/2020 18:45, Ferruh Yigit:
>> On 9/13/2020 11:07 PM, Thomas Monjalon wrote:
>>> Since rte_eth_dev_release_port() is called on all port close operations,
>>> the event RTE_ETH_EVENT_DESTROY can be reliably used for resetting
>>> the port status on the application side.
>>>
>>> The intermediate state RTE_PORT_HANDLING is removed in close_port()
>>> because a port can also be closed by a PMD in a device remove operation.
>>>
>>> In case multiple ports are closed, calling remove_invalid_ports()
>>> only once is enough.
>>>
>>> Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
>>
>> <...>
>>
>>> @@ -3118,6 +3093,13 @@ eth_event_callback(portid_t port_id, enum rte_eth_event_type type, void *param,
>>>    				rmv_port_callback, (void *)(intptr_t)port_id))
>>>    			fprintf(stderr, "Could not set up deferred device removal\n");
>>>    		break;
>>> +	case RTE_ETH_EVENT_DESTROY:
>>> +		if (rte_atomic16_cmpset(&(ports[port_id].port_status),
>>> +					RTE_PORT_STOPPED,
>>> +					RTE_PORT_CLOSED) == 0)
>>> +			printf("Port %d cannot be set to closed\n", port_id);
>>> +		printf("Port %u is closed\n", port_id);
>>> +		break;
>>
>> This is failing if a port closed without application port stop command,
>> PMD may be doing port stop within the close function but since
>> application didn't give the stop command, the port status is not
>> 'RTE_PORT_STOPPED', hence 'port_status' is not updated correctly.
> 
> Do you think we should give up with the atomic state transition,
> and just assign the state as closed?
> 

It can be better, if the DESTROY event received it should be in closed 
state.

Right now device can be hot removed while running, or it may be closed 
before it has been stopped, both cases state transition assumption from 
stopped->closed will be wrong, and final state will be wrong.