Re: [QUEUED v20180920 05/16] stm class: Add a helper for writing data packets

[Alexander Shishkin]

Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> writes:

>> +static ssize_t notrace stm_write(struct stm_data *data, unsigned int master,
>> +			  unsigned int channel, const char *buf, size_t count)
>> +{
>> +	ssize_t sz;
>> +
>> +	sz = stm_data_write(data, master, channel, true, buf, count);
>> +	if (sz > 0)
>> +		data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0,
>> +			     buf);
>
> The original code the payload of a flag packet was '0' while in this patch
> changes it to be anything.  Some external tooling could be very confused.

I think the original intention was so: the 'size' field of ->packet()
refers to how many bytes from the given 'payload' the callback should
use. IOW, with size 0, buf may point to anything (still a valid pointer
though). But that should have been documented better from the beginning,
so you're completely right. I'll make a note to myself to go over the
API bits and sort out stuff like that.

Thanks,
--
Alex