linux-kernel - Re: [PATCH 2/2] net: macb: kill useless use of list

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Message-ID: <40553101-3ebf-0559-363e-f982d8494968@microchip.com>
Date:   Tue, 5 Dec 2017 22:28:40 +0100
From:   Nicolas Ferre <nicolas.ferre@...rochip.com>
To:     Julia Cartwright <julia@...com>,
        Julia Lawall <julia.lawall@...6.fr>
CC:     Rafal Ozieblo <rafalo@...ence.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <kbuild-all@...org>
Subject: Re: [PATCH 2/2] net: macb: kill useless use of list_empty()

On 05/12/2017 at 21:18, Julia Cartwright wrote:
> The list_for_each_entry() macro already handles the case where the list
> is empty (by not executing the loop body).  It's not necessary to handle
> this case specially, so stop doing so.
> 
> Cc: Rafal Ozieblo <rafalo@...ence.com>
> Signed-off-by: Julia Cartwright <julia@...com>
> ---
> This is an additional cleanup patch found when looking at this code.
> 
>    Julia

Acked-by: Nicolas Ferre <nicolas.ferre@...rochip.com>

Thanks

> 
>  drivers/net/ethernet/cadence/macb_main.c | 34 ++++++++++++--------------------
>  1 file changed, 13 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index e7ef104a077d..3643c6ad2322 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2815,25 +2815,22 @@ static int gem_add_flow_filter(struct net_device *netdev,
>  	spin_lock_irqsave(&bp->rx_fs_lock, flags);
>  
>  	/* find correct place to add in list */
> -	if (list_empty(&bp->rx_fs_list.list))
> -		list_add(&newfs->list, &bp->rx_fs_list.list);
> -	else {
> -		list_for_each_entry(item, &bp->rx_fs_list.list, list) {
> -			if (item->fs.location > newfs->fs.location) {
> -				list_add_tail(&newfs->list, &item->list);
> -				added = true;
> -				break;
> -			} else if (item->fs.location == fs->location) {
> -				netdev_err(netdev, "Rule not added: location %d not free!\n",
> -						fs->location);
> -				ret = -EBUSY;
> -				goto err;
> -			}
> +	list_for_each_entry(item, &bp->rx_fs_list.list, list) {
> +		if (item->fs.location > newfs->fs.location) {
> +			list_add_tail(&newfs->list, &item->list);
> +			added = true;
> +			break;
> +		} else if (item->fs.location == fs->location) {
> +			netdev_err(netdev, "Rule not added: location %d not free!\n",
> +					fs->location);
> +			ret = -EBUSY;
> +			goto err;
>  		}
> -		if (!added)
> -			list_add_tail(&newfs->list, &bp->rx_fs_list.list);
>  	}
>  
> +	if (!added)
> +		list_add_tail(&newfs->list, &bp->rx_fs_list.list);
> +
>  	gem_prog_cmp_regs(bp, fs);
>  	bp->rx_fs_list.count++;
>  	/* enable filtering if NTUPLE on */
> @@ -2859,11 +2856,6 @@ static int gem_del_flow_filter(struct net_device *netdev,
>  
>  	spin_lock_irqsave(&bp->rx_fs_lock, flags);
>  
> -	if (list_empty(&bp->rx_fs_list.list)) {
> -		spin_unlock_irqrestore(&bp->rx_fs_lock, flags);
> -		return -EINVAL;
> -	}
> -
>  	list_for_each_entry(item, &bp->rx_fs_list.list, list) {
>  		if (item->fs.location == cmd->fs.location) {
>  			/* disable screener regs for the flow entry */
> 


-- 
Nicolas Ferre