Re: [PATCH net-next 02/15] net: dsa: sja1105: Remove usage of iterator for list_add() after loop

Jakub Kicinski
2022-04-08T03:56:43Z

On Thu, 7 Apr 2022 12:28:47 +0200 Jakob Koschel wrote:
> diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c
> index b7e95d60a6e4..cfcae4d19eef 100644
> --- a/drivers/net/dsa/sja1105/sja1105_vl.c
> +++ b/drivers/net/dsa/sja1105/sja1105_vl.c
> @@ -27,20 +27,24 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg,
> if (list_empty(&gating_cfg->entries)) {
> list_add(&e->list, &gating_cfg->entries);
> } else {
> - struct sja1105_gate_entry *p;
> + struct sja1105_gate_entry *p = NULL, *iter;
>
> - list_for_each_entry(p, &gating_cfg->entries, list) {
> - if (p->interval == e->interval) {
> + list_for_each_entry(iter, &gating_cfg->entries, list) {
> + if (iter->interval == e->interval) {
> NL_SET_ERR_MSG_MOD(extack,
> "Gate conflict");
> rc = -EBUSY;
> goto err;
> }
>
> - if (e->interval < p->interval)
> + if (e->interval < iter->interval) {
> + p = iter;
> + list_add(&e->list, iter->list.prev);
> break;
> + }
> }
> - list_add(&e->list, p->list.prev);
> + if (!p)
> + list_add(&e->list, gating_cfg->entries.prev);

This turns a pretty slick piece of code into something ugly :(
I'd rather you open coded the iteration here than make it more
complex to satisfy "safe coding guidelines".

Also the list_add() could be converted to list_add_tail().