Re: [PATCH v5 1/5] counter: Internalize sysfs interface code

[William Breathitt Gray]

On Wed, Oct 14, 2020 at 08:38:40PM -0500, David Lechner wrote:
> On 9/26/20 9:18 PM, William Breathitt Gray wrote:
> > +static ssize_t counter_comp_u8_store(struct device *dev,
> > +				     struct device_attribute *attr,
> > +				     const char *buf, size_t len)
> > +{
> > +	const struct counter_attribute *const a = to_counter_attribute(attr);
> > +	struct counter_device *const counter = dev_get_drvdata(dev);
> > +	struct counter_count *const count = a->parent;
> > +	struct counter_synapse *const synapse = a->comp.priv;
> > +	const struct counter_available *const avail = a->comp.priv;
> > +	int err;
> > +	bool bool_data;
> > +	u8 data;
> > +
> > +	switch (a->comp.type) {
> > +	case COUNTER_COMP_BOOL:
> > +		err = kstrtobool(buf, &bool_data);
> > +		data = bool_data;
> > +		break;
> > +	case COUNTER_COMP_FUNCTION:
> > +		err = find_in_string_array(&data, count->functions_list,
> > +					   count->num_functions, buf,
> > +					   counter_function_str);
> > +		break;
> > +	case COUNTER_COMP_SYNAPSE_ACTION:
> > +		err = find_in_string_array(&data, synapse->actions_list,
> > +					   synapse->num_actions, buf,
> > +					   counter_synapse_action_str);
> > +		break;
> > +	case COUNTER_COMP_ENUM:
> > +		err = __sysfs_match_string(avail->strs, avail->num_items, buf);
> > +		data = err;
> > +		break;
> > +	case COUNTER_COMP_COUNT_MODE:
> > +		err = find_in_string_array(&data, avail->enums,
> > +					   avail->num_items, buf,
> > +					   counter_count_mode_str);
> > +		break;
> > +	default:
> > +		err = kstrtou8(buf, 0, &data);
> > +		break;
> > +	}
> 
> In this function, return values are not always errors. So it would make
> sense to call the err variable ret instead and check for ret < 0 below.
> 
> Setting enums to a value with index > 0 fails currently because of this.

Thank you for pointing this out, I'll fix this.

William Breathitt Gray

> > +	if (err)
> > +		return err;
> > +
> > +	switch (a->scope) {
> > +	case COUNTER_SCOPE_DEVICE:
> > +		err = a->comp.device_u8_write(counter, data);
> > +		break;
> > +	case COUNTER_SCOPE_SIGNAL:
> > +		err = a->comp.signal_u8_write(counter, a->parent, data);
> > +		break;
> > +	case COUNTER_SCOPE_COUNT:
> > +		if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
> > +			err = a->comp.action_write(counter, count, synapse,
> > +						   data);
> > +		else
> > +			err = a->comp.count_u8_write(counter, count, data);
> > +		break;
> > +	}
> > +	if (err)
> > +		return err;
> > +
> > +	return len;
> > +}
>

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