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Date: Tue, 26 Jun 2012 16:37:38 +0300
From: Shmulik Ladkani <shmulik.ladkani@gmail.com>
To: Brian Norris <computersforpeace@gmail.com>
Subject: Re: [PATCH 7/8] mtd: nand_bbt: use string library
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Cc: David Woodhouse <dwmw2@infradead.org>, linux-mtd@lists.infradead.org,
 Akinobu Mita <akinobu.mita@gmail.com>, Artem Bityutskiy <dedekind1@gmail.com>
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Hi Brian,

On Fri, 22 Jun 2012 16:35:44 -0700 Brian Norris <computersforpeace@gmail.com> wrote:
>  static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
>  {
> -	int i, end = 0;
> +	int end = 0;
>  	uint8_t *p = buf;
>  
>  	if (td->options & NAND_BBT_NO_OOB)
>  		return check_pattern_no_oob(buf, td);
>  
>  	end = paglen + td->offs;
> -	if (td->options & NAND_BBT_SCANEMPTY) {
> -		for (i = 0; i < end; i++) {
> -			if (p[i] != 0xff)
> -				return -1;
> -		}
> -	}
> +	if (td->options & NAND_BBT_SCANEMPTY)
> +		if (memchr_inv(p, 0xff, end))
> +			return -1;
>  	p += end;
>  

A question regarding the original code:
Why the region validated for 0xff is [0 , paglen+td->of) ?
I assume this buffer region contains the inband data. Why verify inband
data is all 0xff?
Shouldn't the region validated be [paglen , paglen+td->of) ?

Regards,
Shmulik