On Mon, Aug 01, 2022 at 01:50:39PM -0700, Hao Luo wrote:
SNIP
> +static int do_seq_show(struct seq_file *seq, void *p, size_t offs)
> +{
> + int err;
> +
> + WARN_ON(IS_ERR_OR_NULL(p));
> +
> + err = seq->op->show(seq, p);
> + if (err > 0) {
> + /* object is skipped, decrease seq_num, so next
> + * valid object can reuse the same seq_num.
> + */
> + bpf_iter_dec_seq_num(seq);
> + seq->count = offs;
> + return err;
> + }
> +
> + if (err < 0 || seq_has_overflowed(seq)) {
> + seq->count = offs;
> + return err ? err : -E2BIG;
> + }
> +
> + /* err == 0 and no overflow */
> + return 0;
> +}
> +
> +/* do_seq_stop, stops at the given object 'p'. 'p' could be an ERR or NULL. If
> + * 'p' is an ERR or there was an overflow, reset seq->count to 'offs' and
> + * returns error. Returns 0 otherwise.
> + */
> +static int do_seq_stop(struct seq_file *seq, void *p, size_t offs)
> +{
> + if (IS_ERR(p)) {
> + seq->op->stop(seq, NULL);
> + seq->count = offs;
should we set seq->count to 0 in case of error?
jirka
> + return PTR_ERR(p);
> + }
> +
> + seq->op->stop(seq, p);
> + if (!p) {
> + if (!seq_has_overflowed(seq)) {
> + bpf_iter_done_stop(seq);
> + } else {
> + seq->count = offs;
> + if (offs == 0)
> + return -E2BIG;
> + }
> + }
> + return 0;
> +}
> +
> /* maximum visited objects before bailing out */
> #define MAX_ITER_OBJECTS 1000000
>
SNIP
