>>> +static void *seq_next(struct seq_file *m, void *p, loff_t *pos)
>>> +{
>>> + struct proc_fdinfo_extra *extra = m->private;
>>> + void *v = NULL;
>>> +
>>> + if (extra->driver) {
>>> + int ret = 0;
>>> +
>>> + if (*pos == 0) {
>>> + v = extra->driver->ops->start(m, pos);
>>> + if (v) {
>>> + ret = extra->driver->ops->show(m, v);
>>
>> Why is it necessary to call ->show here? The logic should be
>>
>> seq_start = (pos == 0 ? nop : extra->start)
>> seq_next = (pos == 0 ? extra->start : extra->next)
>> seq_stop = (pos == 0 ? nop : extra->stop)
>> seq_show = (pos == 0 ? proc_show : extra->show)
>>
>> Or I'm missing something?
>
> Well, I thought about it as two sequences -- first is procfs
> seq-file, which prints out a general header, and second
> is extra fdinfo provider.
>
> Everything starts with printing procfs header
>
> seq_start -> seq_show (prints "pos:\t%lli\nflags:\t0%o\n") ->
> seq_next -> (if have extra driver we do extra's start/show at first,
Why show? The generic seq_file.c will call ->next (which will result in
extra->start), then ->show (which _should_ result in extra->show) thus
providing correct output.
> then next and etc). In other words general header should be
> shown always even if extra's start() fails.
>
> Cyrill
> .
>
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