[PATCH] Fix corner case in bad block table handling.

[Richard Weinberger]

On Wed, Jul 15, 2020 at 4:54 PM Doyle, Patrick <pdoyle at irobot.com> wrote:
>
>
>
> In the unlikely event that both blocks 10 and 11 are marked as bad (on a
> 32 bit machine), then the process of marking block 10 as bad stomps on
> cached entry for block 11.  There are (of course) other examples.
>
> Signed-off-by: Patrick Doyle <pdoyle at irobot.com>
> ---
>  drivers/mtd/nand/bbt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/bbt.c b/drivers/mtd/nand/bbt.c
> index 7e0ad3190c..eb1184aadb 100644
> --- a/drivers/mtd/nand/bbt.c
> +++ b/drivers/mtd/nand/bbt.c
> @@ -124,7 +124,7 @@ int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
>                 unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
>
>                 pos[1] &= ~GENMASK(rbits - 1, 0);
> -               pos[1] |= val >> rbits;
> +               pos[1] |= val >> (bits_per_block - rbits);

Looks good to me.

Fixes: 9c3736a3de21 ("mtd: nand: Add core infrastructure to deal with
NAND devices")
Reviewed-by: Richard Weinberger <richard at nod.at>

--
Thanks,
//richard