Re: [PATCH v2 2/2] alloc_tag: keep codetag iterator active between read() calls

Tim Chen
2025-05-09T18:33:55Z

On Sat, 2025-05-10 at 01:39 +0800, David Wang wrote:
>
>
> Signed-off-by: David Wang <00107082@163.com>
> ---
> lib/alloc_tag.c | 29 ++++++++++-------------------
> 1 file changed, 10 insertions(+), 19 deletions(-)
>
> diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
> index 25ecc1334b67..fdd5887769a6 100644
> --- a/lib/alloc_tag.c
> +++ b/lib/alloc_tag.c
> @@ -45,21 +45,16 @@ struct allocinfo_private {
> static void *allocinfo_start(struct seq_file *m, loff_t *pos)
> {
> struct allocinfo_private *priv;
> - struct codetag *ct;
> loff_t node = *pos;
>
> - priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> - m->private = priv;
> - if (!priv)
> - return NULL;
> -
> - priv->print_header = (node == 0);
> + priv = (struct allocinfo_private *)m->private;
> codetag_lock_module_list(alloc_tag_cttype, true);
> - priv->iter = codetag_get_ct_iter(alloc_tag_cttype);
> - while ((ct = codetag_next_ct(&priv->iter)) != NULL && node)
> - node--;
> -
> - return ct ? priv : NULL;
> + if (node == 0) {
> + priv->print_header = true;
> + priv->iter = codetag_get_ct_iter(alloc_tag_cttype);
> + codetag_next_ct(&priv->iter);
> + }

Do you need to skip print header when *pos != 0? i.e add

} else {
priv->print_header = false;
}

Tim

> + return priv->iter.ct ? priv : NULL;
> }
>