Re: [PATCH] mtd: rawnand: meson: fix bit map use in meson_nfc_ecc_correct()

[Liang Yang <liang.yang@xxxxxxxxxxx>]

Hi Dan,

Thanks.

On 2022/7/28 15:12, Dan Carpenter wrote:
> [ EXTERNAL EMAIL ]
>
> The meson_nfc_ecc_correct() function accidentally does a right shift
> instead of a left shift so it only works for BIT(0).  Also use
> BIT_ULL() because "correct_bitmap" is a u64 and we want to avoid
> shift wrapping bugs.
>
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> > From review.  Untested.
>
>   drivers/mtd/nand/raw/meson_nand.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> index 829b76b303aa..ad2ffd0ca800 100644
> --- a/drivers/mtd/nand/raw/meson_nand.c
> +++ b/drivers/mtd/nand/raw/meson_nand.c
> @@ -454,7 +454,7 @@ static int meson_nfc_ecc_correct(struct nand_chip *nand, u32 *bitflips,
>   		if (ECC_ERR_CNT(*info) != ECC_UNCORRECTABLE) {
>   			mtd->ecc_stats.corrected += ECC_ERR_CNT(*info);
>   			*bitflips = max_t(u32, *bitflips, ECC_ERR_CNT(*info));
> -			*correct_bitmap |= 1 >> i;
> +			*correct_bitmap |= BIT_ULL(i);
>   			continue;
>   		}
>   		if ((nand->options & NAND_NEED_SCRAMBLING) &&
> @@ -800,7 +800,7 @@ static int meson_nfc_read_page_hwecc(struct nand_chip *nand, u8 *buf,
>   			u8 *data = buf + i * ecc->size;
>   			u8 *oob = nand->oob_poi + i * (ecc->bytes + 2);
>   
> -			if (correct_bitmap & (1 << i))
> +			if (correct_bitmap & BIT_ULL(i))
>   				continue;
>   			ret = nand_check_erased_ecc_chunk(data,	ecc->size,
>   							  oob, ecc->bytes + 2,

Acked-by: Liang Yang <liang.yang@xxxxxxxxxxx>

Thanks,
Liang