netdev - Re: [PATCH][next] net: hinic: fix comparison of a uint16

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Date:   Thu, 24 Aug 2017 11:48:32 +0300
From:   Aviad Krawczyk <aviad.krawczyk@...wei.com>
To:     Colin King <colin.king@...onical.com>, <netdev@...r.kernel.org>
CC:     <kernel-janitors@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with
 -1

On 8/23/2017 6:39 PM, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The comparison of hw_ioctxt.rx_buf_sz_idx == -1 is always false because
> rx_buf_sz_idx is a uint16_t. Fix this by explicitly casting -1 to uint16_t.
> 
> Detected by CoverityScan, CID#1454559 ("Operands don't affect result")
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> index 09dec6de8dd5..71e26070fb7f 100644
> --- a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> +++ b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> @@ -352,7 +352,7 @@ static int set_hw_ioctxt(struct hinic_hwdev *hwdev, unsigned int rq_depth,
>  		}
>  	}
>  
> -	if (hw_ioctxt.rx_buf_sz_idx == -1)
> +	if (hw_ioctxt.rx_buf_sz_idx == (uint16_t)-1)
>  		return -EINVAL;
>  
>  	hw_ioctxt.sq_depth  = ilog2(sq_depth);
> 

Many thanks, Colin.
I prefer to avoid casting when possible, what do you think about replacing the condition by:

if (rx_buf_sz_table[i].sz != HINIC_RX_BUF_SZ)
	return -EINVAL;