Re: [dpdk-dev] [PATCH] net/i40evf: fix casting between structs

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 11/27/2016 9:35 AM, Jingjing Wu wrote:
> Casting from structs which lay out data in typed members
> to structs which have flat memory buffers, will cause
> problems if the alignment of the former isn't as expected.
> This patch removes the casting between structs.
> 
> Fixes: ae19955e7c86 ("i40evf: support reporting PF reset")
> Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
> ---
>  drivers/net/i40e/i40e_ethdev_vf.c | 27 +++++++++++++++------------
>  1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
> index aa306d6..53d7c87 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -1336,8 +1336,9 @@ i40evf_handle_aq_msg(struct rte_eth_dev *dev)
>  	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>  	struct i40e_vf *vf = I40EVF_DEV_PRIVATE_TO_VF(dev->data->dev_private);
>  	struct i40e_arq_event_info info;
> -	struct i40e_virtchnl_msg *v_msg;
> -	uint16_t pending, opcode;
> +	uint16_t pending, aq_opc;
> +	enum i40e_virtchnl_ops msg_opc;
> +	enum i40e_status_code msg_ret;
>  	int ret;
>  
>  	info.buf_len = I40E_AQ_BUF_SZ;
> @@ -1346,7 +1347,6 @@ i40evf_handle_aq_msg(struct rte_eth_dev *dev)
>  		return;
>  	}
>  	info.msg_buf = vf->aq_resp;
> -	v_msg = (struct i40e_virtchnl_msg *)&info.desc;
>  
>  	pending = 1;
>  	while (pending) {
> @@ -1357,32 +1357,35 @@ i40evf_handle_aq_msg(struct rte_eth_dev *dev)
>  				    "ret: %d", ret);
>  			break;
>  		}
> -		opcode = rte_le_to_cpu_16(info.desc.opcode);
> -
> -		switch (opcode) {
> +		aq_opc = rte_le_to_cpu_16(info.desc.opcode);
> +		msg_opc = (enum i40e_virtchnl_ops)rte_le_to_cpu_32(
> +						  info.desc.cookie_high);
> +		msg_ret = (enum i40e_status_code)rte_le_to_cpu_32(
> +						  info.desc.cookie_low);

What do you think commenting cookie_high is opcode and cookie_low is
return_value?

> +		switch (aq_opc) {
>  		case i40e_aqc_opc_send_msg_to_vf:
> -			if (v_msg->v_opcode == I40E_VIRTCHNL_OP_EVENT)
> +			if (msg_opc == I40E_VIRTCHNL_OP_EVENT)
>  				/* process event*/
>  				i40evf_handle_pf_event(dev, info.msg_buf,
>  						       info.msg_len);
>  			else {
>  				/* read message and it's expected one */
> -				if (v_msg->v_opcode == vf->pend_cmd) {
> -					vf->cmd_retval = v_msg->v_retval;
> +				if (msg_opc == vf->pend_cmd) {
> +					vf->cmd_retval = msg_ret;
>  					/* prevent compiler reordering */
>  					rte_compiler_barrier();
>  					_clear_cmd(vf);
>  				} else
>  					PMD_DRV_LOG(ERR, "command mismatch,"
>  						"expect %u, get %u",
> -						vf->pend_cmd, v_msg->v_opcode);
> +						vf->pend_cmd, msg_ret);

s/msg_ret/msg_opc/ ?

>  				PMD_DRV_LOG(DEBUG, "adminq response is received,"
> -					     " opcode = %d\n", v_msg->v_opcode);
> +					     " opcode = %d\n", msg_ret);

s/msg_ret/msg_opc/ ?

>  			}
>  			break;
>  		default:
>  			PMD_DRV_LOG(ERR, "Request %u is not supported yet",
> -				    opcode);
> +				    aq_opc);
>  			break;
>  		}
>  	}
>