Messages in this thread | | | Date | Wed, 31 Oct 2018 14:55:05 +0100 | From | Boris Brezillon <> | Subject | Re: [PATCH] mtd: cast to u64 to avoid unexpected error |
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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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