[PATCH V2 3/6] ethdev: fix push new event

[lihuisong (C)]

在 2022/9/27 18:49, Thomas Monjalon 写道:
> 15/09/2022 14:45, Huisong Li:
>> The 'state' in struct rte_eth_dev may be used to update some information
>> when app receive these events. For example, when app receives a new event,
>> app may get the socket id of this port by calling rte_eth_dev_socket_id to
>> setup the attached port. The 'state' is used in rte_eth_dev_socket_id.
>>
>> If the state isn't modified to RTE_ETH_DEV_ATTACHED before pushing the new
>> event, app will get the socket id failed. So this patch moves pushing event
>> operation after the state updated.
>>
>> Fixes: 99a2dd955fba ("lib: remove librte_ prefix from directory names")
>> Cc: stable at dpdk.org
>>
>> Signed-off-by: Huisong Li <lihuisong at huawei.com>
>> ---
>>   lib/ethdev/ethdev_driver.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/lib/ethdev/ethdev_driver.c b/lib/ethdev/ethdev_driver.c
>> index a285f213f0..a6616f072b 100644
>> --- a/lib/ethdev/ethdev_driver.c
>> +++ b/lib/ethdev/ethdev_driver.c
>> @@ -206,9 +206,9 @@ rte_eth_dev_probing_finish(struct rte_eth_dev *dev)
>>   	if (rte_eal_process_type() == RTE_PROC_SECONDARY)
>>   		eth_dev_fp_ops_setup(rte_eth_fp_ops + dev->data->port_id, dev);
>>   
>> -	rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_NEW, NULL);
>>   
>>   	dev->state = RTE_ETH_DEV_ATTACHED;
>> +	rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_NEW, NULL);
>>   }
> As explained in the first patch, I don't think it is a good solution.
> We should not allow the port to be used until the end of probing.
> When RTE_ETH_EVENT_NEW is sent, the device is allocated but
> not ready for use. If an entity like failsafe decides to take ownership
> of the port, then the application should not consider it at all.
> For these reasons, we should limit which operations can be done
> during RTE_ETH_EVENT_NEW processing.
> That's why I've proposed creating a new state RTE_ETH_DEV_ALLOCATED,
> not sure why you didn't follow this advice.
I want to put this problem to this case this patchset mentions, so as to
have a better discussion. From the first patch, I know what you mean.
But I still have some confusion:
When a device taken by failsafe PMD push new event, all event callback
will be called under this device. As you suggested, the device is a valid
port if its state is ALLOCATED or ATTACHED. Now, the macro 
RTE_ETH_FOREACH_DEV
uses the condition that device is valid(state is ALLOCATED or ATTACHED)
and NOT owned.

Even if we add the new ALLOCATED state, this device taken by failsafe is
also a valid port in new event callback in application, and is in 'NO 
OWNER'.
if event callback of application is called before one of failsafe PMD.
As a result, application still can operate this device directly.
Can we make sure that event callback of failsafe PMD is before one of 
application?
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