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SubjectRe: [PATCH] mtd: cast to u64 to avoid unexpected error
Hi Huijin,

Subject prefix should be "mtd: spi-nor: ...", and please replace
"unexpected error" by "unsigned int overflows".

On Thu, 23 Aug 2018 03:28:02 -0400
Huijin Park <huijin.park@samsung.com> wrote:

> From: "huijin.park" <huijin.park@samsung.com>
>
> the params->size is defined as "u64"
> and, "info->sector_size" and "info->n_sectors" is defined as unsgined and u16

^ are ^ unsigned

> thus, u64 data might have strange data(loss data) if data is overflow.

^ if the result
overflows an unsigned int.

> this patch cast it to u64.

^casts info->sector_size to an u64.

>
> Signed-off-by: huijin.park <huijin.park@samsung.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index d9c368c..527f281 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -2459,7 +2459,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
> memset(params, 0, sizeof(*params));
>
> /* Set SPI NOR sizes. */
> - params->size = info->sector_size * info->n_sectors;
> + params->size = (u64)info->sector_size * (u64)info->n_sectors;

^ this cast is not needed.

BTW, I doubt we'll ever have to deal with NORs that are more than 4GB,
but making static code analysis tools happy and enforcing code
correctness is important too.

> params->page_size = info->page_size;
>
> /* (Fast) Read settings. */

Regards,

Boris

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