Re: [RFC PATCH -next 07/16] mm/damon/sysfs: implement addr_unit file under context dir

[Quanmin Yan <yanquanmin1@huawei.com>]

Hi SJ,

在 2025/8/19 14:24, SeongJae Park 写道:
> Hi Quanmin,
>
> As I suggested on another reply[1], please squash attaching patch to this one
> when you post next version of this series.
>
> [1] https://lore.kernel.org/20250813170224.6128-1-sj@kernel.org
>
> [...]
>
>
> Thanks,
> SJ
>
> ==== Attachment 0 (0001-mm-damon-sysfs-return-EINVAL-for-zero-addr_unit.patch) ====
>  From e0a5aa5e571ecd0f58b0914f8fc8562a60014ae8 Mon Sep 17 00:00:00 2001
> From: SeongJae Park <sj@kernel.org>
> Date: Wed, 13 Aug 2025 21:17:03 -0700
> Subject: [PATCH] mm/damon/sysfs: return -EINVAL for zero addr_unit
>
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
>   mm/damon/sysfs.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index bea782b0a711..eb4269383bae 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -1422,6 +1422,8 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
>   	err = damon_select_ops(ctx, sys_ctx->ops_id);
>   	if (err)
>   		return err;
> +	if (!sys_ctx->addr_unit)
> +		return -EINVAL;
>   	ctx->addr_unit = sys_ctx->addr_unit;
>   	err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
>   	if (err)

Aha, returning -EINVAL when sys_ctx->addr_unit is 0 makes sense, but I wonder if it
might be better to prevent users from inputting 0 at the source instead? I've attempted
to modify patch 7 by adding a check in addr_unit_store. I'll send out the v2 version
of patch 7 later (PS: I am performing a comprehensive validation of the v2 patch series),
and we can discuss it then.

Thanks,
Quanmin Yan