[U-Boot] [PATCH 3/4] usb: ums: fix bug in partition capacity computation.

[Marek Vasut]

Dear Przemyslaw Marczak,

> Before this change ums disk capacity was miscalculated because
> of integer overflow.
> 
> Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
> Cc: Marek Vasut <marex at denx.de>
> ---
>  board/samsung/common/ums.c |   16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/board/samsung/common/ums.c b/board/samsung/common/ums.c
> index 1f28590..6c4e6c4 100644
> --- a/board/samsung/common/ums.c
> +++ b/board/samsung/common/ums.c
> @@ -37,11 +37,19 @@ static int ums_write_sector(struct ums *ums_dev,
> 
>  static void ums_get_capacity(struct ums *ums_dev, long long int *capacity)
>  {
> -	long long int tmp_capacity;
> +	int64_t mmc_capacity = (int64_t)ums_dev->mmc->capacity;

Why are these casts here?

> +	int64_t ums_capacity = (int64_t)ums_dev->part_size * SECTOR_SIZE;
> +	int64_t ums_offset = (int64_t)ums_dev->offset * SECTOR_SIZE;

And here all around? And why are these values signed, can there ever be negative 
value in them?

> -	tmp_capacity = (long long int)((ums_dev->offset + ums_dev->part_size)
> -				       * SECTOR_SIZE);
> -	*capacity = ums_dev->mmc->capacity - tmp_capacity;
> +	if (ums_capacity && ((ums_capacity + ums_offset) < mmc_capacity))
> +		*capacity = ums_capacity;
> +	else
> +		*capacity = mmc_capacity - ums_offset;

Urgh, what exactly does this code achieve again?

> +	printf("UMS: partition capacity: %#llx blocks\n"
> +	       "UMS: partition start block: %#x\n",
> +	       *capacity / SECTOR_SIZE,
> +	       ums_dev->offset);
>  }
> 
>  static struct ums ums_dev = {

Best regards,
Marek Vasut