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Subject[PATCH 2/2 v2] mmc: cast unsigned int to typeof(sector_t) to avoid unexpected error
Date
From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

card->csd.capacity is defined as "unsigned int", and sector_t is defined as
"u64" or "unsigned long" (depends on CONFIG_LBDAF). Thus, sector_t data
might have strange data (see below). This patch cast it to typeof(sector_t)
Special thanks to coverity <http://www.coverity.com>

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

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
v1 -> v2

- tidyup log comment
- tidyup line over 80 characters

drivers/mmc/card/block.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 60f7141..029a872 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2217,7 +2217,8 @@ 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,
--
1.9.1


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