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

Przemyslaw Marczak
2013-10-16T13:21:13Z

Before this change ums disk capacity was miscalculated because
of integer overflow.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Marek Vasut <marex@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;
+ int64_t ums_capacity = (int64_t)ums_dev->part_size * SECTOR_SIZE;
+ int64_t ums_offset = (int64_t)ums_dev->offset * SECTOR_SIZE;

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

static struct ums ums_dev = {
--
1.7.9.5