Linux Ethernet Bridging - Nov 2018 - [Bridge] [PATCH net-next v2 1/3] net: bridge: add support for user-controlled bool options

> +int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool
on,
> +		      struct netlink_ext_ack *extack)
> +{
> +	switch (opt) {
> +	default:
> +		/* shouldn't be called with unsupported options */
> +		WARN_ON(1);
> +		break;
So you return 0 here, meaning the br_debug() lower down will not
happen. Maybe return -EOPNOTSUPP?
> +	}
> +
> +	return 0;
> +}
> +
> +int br_boolopt_multi_toggle(struct net_bridge *br,
> +			    struct br_boolopt_multi *bm,
> +			    struct netlink_ext_ack *extack)
> +{
> +	unsigned long bitmap = bm->optmask;
> +	int err = 0;
> +	int opt_id;
> +
> +	for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
> +		bool on = !!(bm->optval & BIT(opt_id));
> +
> +		err = br_boolopt_toggle(br, opt_id, on, extack);
> +		if (err) {
> +			br_debug(br, "boolopt multi-toggle error: option: %d current: %d
new: %d error: %d\n",
> +				 opt_id, br_boolopt_get(br, opt_id), on, err);
> +			break;
> +		}
> +	}
Does the semantics of extack allow you to return something even when
there is no error? If there are bits > BR_BOOLOPT_MAX you could return
0, but also add a warning in extack that some bits where not supported
by this kernel.
> +void br_boolopt_multi_get(const struct net_bridge *br,
> +			  struct br_boolopt_multi *bm)
> +{
> +	u32 optval = 0;
> +	int opt_id;
> +
> +	for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
> +		optval |= (br_boolopt_get(br, opt_id) << opt_id);
> +
> +	bm->optval = optval;
> +	bm->optmask = 0;
You liked the idea of setting optmask to indicate which bits this
kernel supports. Did you change your mind?

       Andrew

On 24 November 2018 18:10:41 EET, Andrew Lunn <andrew at lunn.ch>
wrote:
>> +int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt,
>bool on,
>> +		      struct netlink_ext_ack *extack)
>> +{
>> +	switch (opt) {
>> +	default:
>> +		/* shouldn't be called with unsupported options */
>> +		WARN_ON(1);
>> +		break;
>
>So you return 0 here, meaning the br_debug() lower down will not
>happen. Maybe return -EOPNOTSUPP?
>
No, the idea here is that some option in the future might return an error. 
This function cannot be called with unsupported option thus the warn. 
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>
>> +int br_boolopt_multi_toggle(struct net_bridge *br,
>> +			    struct br_boolopt_multi *bm,
>> +			    struct netlink_ext_ack *extack)
>> +{
>> +	unsigned long bitmap = bm->optmask;
>> +	int err = 0;
>> +	int opt_id;
>> +
>> +	for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
>> +		bool on = !!(bm->optval & BIT(opt_id));
>> +
>> +		err = br_boolopt_toggle(br, opt_id, on, extack);
>> +		if (err) {
>> +			br_debug(br, "boolopt multi-toggle error: option: %d current:
%d
>new: %d error: %d\n",
>> +				 opt_id, br_boolopt_get(br, opt_id), on, err);
>> +			break;
>> +		}
>> +	}
>
>Does the semantics of extack allow you to return something even when
>there is no error? If there are bits > BR_BOOLOPT_MAX you could return
>0, but also add a warning in extack that some bits where not supported
>by this kernel.
If we return 0 there's no reason to check extack. 
>> +void br_boolopt_multi_get(const struct net_bridge *br,
>> +			  struct br_boolopt_multi *bm)
>> +{
>> +	u32 optval = 0;
>> +	int opt_id;
>> +
>> +	for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
>> +		optval |= (br_boolopt_get(br, opt_id) << opt_id);
>> +
>> +	bm->optval = optval;
>> +	bm->optmask = 0;
>
>You liked the idea of setting optmask to indicate which bits this
>kernel supports. Did you change your mind?
>
Please see patch 03.
>       Andrew

-- 
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