>>> +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 > . > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html