[2/2] mmc: cast unsigned int to typeof(sector_t) to avoid unexpected error

Commit Message

Kuninori Morimoto April 14, 2015, 4:07 a.m. UTC

From: Kuninori Morimoto <[e-mail]>

card->csd.capacity is defined as "unsigned int",
and, sector_t is defined as "u64" or "unsigned long" (depends on CONFIG_LBDAF)
sector_t data might have strange data if first bit of unsigned int
was 1. this patch cast it to typeof(sector_t)

ex) if sector_t was u64

        unsigned int data;
        sector_t sector;

        data = 0x800000;
        sector = (data << 8); // 0xffffffff80000000
        sector = (((typeof(sector_t))data) << 8); // 0x80000000

or

        data = 0x80000000;
        sector = (data << 8); // 0x0
        sector = (((typeof(sector_t))data) << 8); // 0x8000000000

Reported-by: coverity <http://www.coverity.com>
Signed-off-by: Kuninori Morimoto <[e-mail]>
---
 drivers/mmc/card/block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index c69afb5..4d09b0c 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2205,7 +2205,7 @@  static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
 		 * The CSD capacity field is in units of read_blkbits.
 		 * set_capacity takes units of 512 bytes.
 		 */
-		size = card->csd.capacity << (card->csd.read_blkbits - 9);
+		size = (typeof(sector_t))card->csd.capacity << (card->csd.read_blkbits - 9);
 	}
 
 	return mmc_blk_alloc_req(card, &card->dev, size, false, NULL,