Re: [PATCH 2/2] net: macb: kill useless use of list_empty()

From: Nicolas Ferre
Date: Tue Dec 05 2017 - 16:28:54 EST


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@xxxxxxxxxxx>
> Signed-off-by: Julia Cartwright <julia@xxxxxx>
> ---
> This is an additional cleanup patch found when looking at this code.
>
> Julia

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

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