linux-kernel - Re: [PATCH v2 3/3] dm-pcache: zero cache

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Message-ID: <CADSj-VoEF63HPCp5Uip2u94OVgkjbH+SZP6DP-JpCo7tRa6jvg@mail.gmail.com>
Date: Wed, 12 Nov 2025 16:24:14 +0800
From: Zheng Gu <cengku@...il.com>
To: Li Chen <me@...ux.beauty>
Cc: dm-devel@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	Dongsheng Yang <dongsheng.yang@...ux.dev>
Subject: Re: [PATCH v2 3/3] dm-pcache: zero cache_info before default init

On Tue, Nov 11, 2025 at 8:14 PM Li Chen <me@...ux.beauty> wrote:
>
> From: Li Chen <chenl311@...natelecom.cn>
>
> pcache_meta_find_latest() leaves whatever it last copied into the
> caller’s buffer even when it returns NULL. For cache_info_init(),
> that meant cache->cache_info could still contain CRC-bad garbage when
> no valid metadata exists, leading later initialization paths to read
> bogus flags.
>
> Explicitly memset cache->cache_info in cache_info_init_default()
> so new-cache paths start from a clean slate. The default sequence
> number assignment becomes redundant with this reset, so it drops out.
>
> Signed-off-by: Li Chen <chenl311@...natelecom.cn>
> ---
>  drivers/md/dm-pcache/cache.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
> index d516d4904227..698697a7a73c 100644
> --- a/drivers/md/dm-pcache/cache.c
> +++ b/drivers/md/dm-pcache/cache.c
> @@ -181,7 +181,7 @@ static void cache_info_init_default(struct pcache_cache *cache)
>  {
>         struct pcache_cache_info *cache_info = &cache->cache_info;
>
> -       cache_info->header.seq = 0;
> +       memset(cache_info, 0, sizeof(*cache_info));
>         cache_info->n_segs = cache->cache_dev->seg_num;
>         cache_info_set_gc_percent(cache_info, PCACHE_CACHE_GC_PERCENT_DEFAULT);
>  }
> --
> 2.51.0
>
It looks good to me.

Reviewed-by:  Zheng Gu <cengku@...il.com>