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

["Kinsella, Ray" <mdr@ashroe.eu>]

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.


> +	}
>  	ret = dev->dev_ops->dev_reset(dev);
>  
>  	return eth_err(port_id, ret);
> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> index a61ca115a0..b85861cf2b 100644
> --- a/lib/librte_ethdev/rte_ethdev.h
> +++ b/lib/librte_ethdev/rte_ethdev.h
> @@ -2277,8 +2277,11 @@ int rte_eth_dev_start(uint16_t port_id);
>   *
>   * @param port_id
>   *   The port identifier of the Ethernet device.
> + * @return
> + *   - 0: Success, Ethernet device stopped.
> + *   - <0: Error code of the driver device stop function.
>   */
> -void rte_eth_dev_stop(uint16_t port_id);
> +int rte_eth_dev_stop(uint16_t port_id);
>  
>  /**
>   * Link up an Ethernet device.
>