linux-kernel - Re: [PATCH v2 1/1] mtd: ubi: skip programming unused bits in ubi headers

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Message-ID: <87qzu1f218.fsf@bootlin.com>
Date: Fri, 14 Nov 2025 09:31:47 +0100
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Cheng Ming Lin <linchengming884@...il.com>
Cc: richard@....at,  chengzhihao1@...wei.com,  vigneshr@...com,
  linux-mtd@...ts.infradead.org,  linux-kernel@...r.kernel.org,
  alvinzhou@...c.com.tw,  leoyu@...c.com.tw,  Cheng Ming Lin
 <chengminglin@...c.com.tw>
Subject: Re: [PATCH v2 1/1] mtd: ubi: skip programming unused bits in ubi
 headers

Hi Cheng Ming,

> @@ -1150,6 +1152,14 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
>  		return -EROFS;
>  	}
>  
> +	if (ubi->vid_hdr_shift) {
> +		memset((char *)p, 0xFF, ubi->vid_hdr_shift);
> +		memset((char *)p + ubi->vid_hdr_shift + UBI_VID_HDR_SIZE, 0xFF,
> +		       ubi->vid_hdr_alsize - (ubi->vid_hdr_shift + UBI_VID_HDR_SIZE));
> +	} else {
> +		memset((char *)p + UBI_VID_HDR_SIZE, 0xFF, ubi->vid_hdr_alsize - UBI_VID_HDR_SIZE);
> +	}
> +

Is it not possible to memset() the buffer before writing the VID header?
I haven't found quickly a good place to do that, so in any case,

Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>

Thanks,
Miquèl