[U-Boot] [PATCH] Fix computation in nand_util.c:get_len_incl_bad

[U-Boot] [PATCH] Fix computation in nand_util.c:get_len_incl_bad

[Daniel Hobi]

Depending on offset, flash size and the number of bad blocks,
get_len_incl_bad may return a too small value which may lead to:

1) If there are no bad blocks, nand_{read,write}_skip_bad chooses the
bad block aware read/write code. This may hurt performance, but does
not have any adverse effects.

2) If there are bad blocks, the nand_{read,write}_skip_bad may choose
the bad block unaware read/write code (if len_incl_bad == *length)
which leads to corrupted data.

Signed-off-by: Daniel Hobi <daniel.hobi@schmid-telecom.ch>
---
@Scott: please review
@Wolfgang: please consider for 2009.11

diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c
index bec9277..7085d42 100644
--- a/drivers/mtd/nand/nand_util.c
+++ b/drivers/mtd/nand/nand_util.c
@@ -452,7 +452,7 @@ static size_t get_len_incl_bad (nand_info_t *nand, loff_t offset,
 		len_incl_bad += block_len;
 		offset       += block_len;
 
-		if ((offset + len_incl_bad) >= nand->size)
+		if (offset >= nand->size)
 			break;
 	}
 
-- 
1.5.6.5

[U-Boot] [PATCH] Fix computation in nand_util.c:get_len_incl_bad

[Scott Wood]

On Tue, Dec 01, 2009 at 02:05:55PM +0100, Daniel Hobi wrote:
> Depending on offset, flash size and the number of bad blocks,
> get_len_incl_bad may return a too small value which may lead to:
> 
> 1) If there are no bad blocks, nand_{read,write}_skip_bad chooses the
> bad block aware read/write code. This may hurt performance, but does
> not have any adverse effects.
> 
> 2) If there are bad blocks, the nand_{read,write}_skip_bad may choose
> the bad block unaware read/write code (if len_incl_bad == *length)
> which leads to corrupted data.

It could also lead to the rejection of accesses near the end of flash.

> Signed-off-by: Daniel Hobi <daniel.hobi@schmid-telecom.ch>
> ---
> @Scott: please review
> @Wolfgang: please consider for 2009.11

Applied to next.  I think it's too late for 2009.12, since it's supposed to
be released tomorrow according to http://www.denx.de/wiki/U-Boot/ReleaseCycle,
and it's not a regression from the previous version.

-Scott

[U-Boot] [PATCH] Fix computation in nand_util.c:get_len_incl_bad

[Wolfgang Denk]

Dear Scott Wood,

In message <20091201235510.GA19547@loki.buserror.net> you wrote:
>
> > @Scott: please review
> > @Wolfgang: please consider for 2009.11
> 
> Applied to next.  I think it's too late for 2009.12, since it's supposed to
> be released tomorrow according to http://www.denx.de/wiki/U-Boot/ReleaseCycle,
> and it's not a regression from the previous version.

Heh. We don't even have -rc2 yet.

Please feel free to send me a pull request if you consider it a fix.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
I had the rare misfortune of being one of the first people to try and
implement a PL/1 compiler.                             -- T. Cheatham

[U-Boot] [PATCH] Fix computation in nand_util.c:get_len_incl_bad

[Wolfgang Denk]

Dear Daniel Hobi,

In message <1259672755-929-1-git-send-email-daniel.hobi@schmid-telecom.ch> you wrote:
> Depending on offset, flash size and the number of bad blocks,
> get_len_incl_bad may return a too small value which may lead to:
> 
> 1) If there are no bad blocks, nand_{read,write}_skip_bad chooses the
> bad block aware read/write code. This may hurt performance, but does
> not have any adverse effects.
> 
> 2) If there are bad blocks, the nand_{read,write}_skip_bad may choose
> the bad block unaware read/write code (if len_incl_bad == *length)
> which leads to corrupted data.
> 
> Signed-off-by: Daniel Hobi <daniel.hobi@schmid-telecom.ch>
> ---
> @Scott: please review
> @Wolfgang: please consider for 2009.11
> 
> diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c

Applied, thanks.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Intelligence without character is a dangerous thing."   - G. Steinem