Hello Joe, Thanks for reviewing this code. Couple of replies.
18-09-2013 15:11, Joe Perches wrote:
> On Wed, 2013-09-18 at 15:02 -0400, Eduardo Valentin wrote:
>> This patch introduces a device tree bindings for
>> describing the hardware thermal behavior and limits.
>> Also a parser to read and interpret the data and feed
>> it in the thermal framework is presented.
>
> trivial notes:
No issues.
>
>> diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
> []
>> +static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
>> + enum thermal_trend *trend)
>> +{
>> + struct __thermal_zone *data = tz->devdata;
>> + long dev_trend;
>> + int r;
>> +
>> + if (!data->get_trend)
>> + return -EINVAL;
>> +
>> + r = data->get_trend(data->sensor_data, &dev_trend);
>> + if (r)
>> + return r;
>> +
>> + if (dev_trend > 0)
>> + *trend = THERMAL_TREND_RAISING;
>> + else if (dev_trend < 0)
>> + *trend = THERMAL_TREND_DROPPING;
>> + else
>> + *trend = THERMAL_TREND_STABLE;
>> +
>> + return 0;
>> +}
>
> If readings are within some non zero noise level,
> perhaps stable should be returned.
Yes, there should be some sort of threshold for temperature trend. But I
am not sure this is the right place to implement this. This type of
feature is in my TODO list, but I am planing to get it done within the
core code of the thermal framework.
>
>> +static struct __thermal_zone *
>> +thermal_of_build_thermal_zone(struct device_node *np)
>> +{
>> + struct device_node *child, *gchild;
>> + struct __thermal_zone *tz;
>> + int ret, i;
>> + u32 prop;
>> +
>> + if (!np) {
>> + pr_err("no thermal zone np\n");
>> + return ERR_PTR(-EINVAL);
>> + }
>> +
>> + tz = kzalloc(sizeof(*tz), GFP_KERNEL);
>> + if (!tz) {
>> + pr_err("not enough memory for thermal of zone\n");
>
> Unnecessary OOM message.
> All allocs without GFP_NOWARN get a dump_stack()
>
>> +int __init of_parse_thermal_zones(void)
>> +{
> []
>> + ops = kzalloc(sizeof(*ops), GFP_KERNEL);
>> + if (!ops) {
>> + pr_err("no memory available for thermal ops\n");
>> + return 0;
>> + }
>> + memcpy(ops, &of_thermal_ops, sizeof(*ops));
>> +
>> + tzp = kzalloc(sizeof(*tzp), GFP_KERNEL);
>> + if (!ops) {
>> + pr_err("no memory available for thermal zone params\n");
>> + return 0;
>> + }
>
> a couple more OOMs.
>
Hmmm.. I am pretty sure you have a good point. But to me seams to be
still a common practice to have drivers outputing error messages when
allocation fails. A simple git grep -A 4 kzalloc for instance, shows
that there are still quite a considerable amount of occurrences of such
practice.
>
>
>
--
You have got to be excited about what you are doing. (L. Lamport)
Eduardo Valentin
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