Re: [dpdk-dev] [PATCH v2 01/11] ethdev: change eth dev stop function to return int

[Andrew Rybchenko <Andrew.Rybchenko@oktetlabs.ru>]

On 10/16/20 2:20 PM, Kinsella, Ray wrote:
>
> On 15/10/2020 14:30, Andrew Rybchenko wrote:
>> From: Ivan Ilchenko <ivan.ilchenko@oktetlabs.ru>
>>
>> Change rte_eth_dev_stop() return value from void to int
>> and return negative errno values in case of error conditions.
>> Also update the usage of the function in ethdev according to
>> the new return type.
>>
>> Signed-off-by: Ivan Ilchenko <ivan.ilchenko@oktetlabs.ru>
>> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> Acked-by: Thomas Monjalon <thomas@monjalon.net>
>> ---
>>   doc/guides/rel_notes/deprecation.rst   |  1 -
>>   doc/guides/rel_notes/release_20_11.rst |  3 +++
>>   lib/librte_ethdev/rte_ethdev.c         | 27 +++++++++++++++++++-------
>>   lib/librte_ethdev/rte_ethdev.h         |  5 ++++-
>>   4 files changed, 27 insertions(+), 9 deletions(-)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
>> index d1f5ed39db..2e04e24374 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -127,7 +127,6 @@ Deprecation Notices
>>     negative errno values to indicate various error conditions (e.g.
>>     invalid port ID, unsupported operation, failed operation):
>>   
>> -  - ``rte_eth_dev_stop``
>>     - ``rte_eth_dev_close``
>>   
>>   * ethdev: New offload flags ``DEV_RX_OFFLOAD_FLOW_MARK`` will be added in 19.11.
>> diff --git a/doc/guides/rel_notes/release_20_11.rst b/doc/guides/rel_notes/release_20_11.rst
>> index f8686a50db..c8c30937fa 100644
>> --- a/doc/guides/rel_notes/release_20_11.rst
>> +++ b/doc/guides/rel_notes/release_20_11.rst
>> @@ -355,6 +355,9 @@ API Changes
>>   * vhost: Add a new function ``rte_vhost_crypto_driver_start`` to be called
>>     instead of ``rte_vhost_driver_start`` by crypto applications.
>>   
>> +* ethdev: changed ``rte_eth_dev_stop`` return value from ``void`` to
>> +  ``int`` to provide a way to report various error conditions.
>> +
>>   
>>   ABI Changes
>>   -----------
>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>> index d9b82df073..b8cf04ef4d 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -1661,7 +1661,7 @@ rte_eth_dev_start(uint16_t port_id)
>>   	struct rte_eth_dev *dev;
>>   	struct rte_eth_dev_info dev_info;
>>   	int diag;
>> -	int ret;
>> +	int ret, ret_stop;
>>   
>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
>>   
>> @@ -1695,7 +1695,13 @@ rte_eth_dev_start(uint16_t port_id)
>>   		RTE_ETHDEV_LOG(ERR,
>>   			"Error during restoring configuration for device (port %u): %s\n",
>>   			port_id, rte_strerror(-ret));
>> -		rte_eth_dev_stop(port_id);
>> +		ret_stop = rte_eth_dev_stop(port_id);
>> +		if (ret_stop != 0) {
>> +			RTE_ETHDEV_LOG(ERR,
>> +				"Failed to stop device (port %u): %s\n",
>> +				port_id, rte_strerror(-ret_stop));
>> +		}
>> +
>>   		return ret;
>>   	}
>>   
>> @@ -1708,26 +1714,28 @@ rte_eth_dev_start(uint16_t port_id)
>>   	return 0;
>>   }
>>   
>> -void
>> +int
>>   rte_eth_dev_stop(uint16_t port_id)
>>   {
>>   	struct rte_eth_dev *dev;
>>   
>> -	RTE_ETH_VALID_PORTID_OR_RET(port_id);
>> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>>   	dev = &rte_eth_devices[port_id];
>>   
>> -	RTE_FUNC_PTR_OR_RET(*dev->dev_ops->dev_stop);
>> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_stop, -ENOTSUP);
>>   
>>   	if (dev->data->dev_started == 0) {
>>   		RTE_ETHDEV_LOG(INFO,
>>   			"Device with port_id=%"PRIu16" already stopped\n",
>>   			port_id);
>> -		return;
>> +		return 0;
>>   	}
>>   
>>   	dev->data->dev_started = 0;
>>   	(*dev->dev_ops->dev_stop)(dev);
>>   	rte_ethdev_trace_stop(port_id);
>> +
>> +	return 0;
>>   }
>>   
>>   int
>> @@ -1783,7 +1791,12 @@ rte_eth_dev_reset(uint16_t port_id)
>>   
>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_reset, -ENOTSUP);
>>   
>> -	rte_eth_dev_stop(port_id);
>> +	ret = rte_eth_dev_stop(port_id);
>> +	if (ret != 0) {
>> +		RTE_ETHDEV_LOG(ERR,
>> +			"Failed to stop device (port %u) before reset: %s - ignore\n",
>> +			port_id, rte_strerror(-ret));
> ABI change is 100%,
> Just question the logic of continuing here to do a reset, if you failed to stop the device.

In the case of reset I'm sure that we should ignore stop failure here.
Typically reset is required to recover from bad state etc and stop
failure in such condition could definitely happen.