[PATCH] mtd: change len type from signed to unsigned type

[PATCH] mtd: change len type from signed to unsigned type

[Huijin Park]

From: "huijin.park" <huijin.park@samsung.com>

assign of a signed value which has type 'int' to a variable of
a bigger unsigned integer type 'uint64_t'.
this is ok most of the time, but can lead to unexpectedly large
resulting value if the original signed value is negative.
in addtion, the callers of the erase_write() pass the len parameter
as unsigned type.

Signed-off-by: huijin.park <huijin.park@samsung.com>
---
 drivers/mtd/mtdblock.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index a5b1933..b2d5ed1 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -56,7 +56,7 @@ struct mtdblk_dev {
  */
 
 static int erase_write (struct mtd_info *mtd, unsigned long pos,
-			int len, const char *buf)
+			unsigned int len, const char *buf)
 {
 	struct erase_info erase;
 	size_t retlen;
-- 
1.7.9.5

Re: [PATCH] mtd: change len type from signed to unsigned type

[Boris Brezillon]

Hi Huijin,

On Thu, 23 Aug 2018 04:43:39 -0400
Huijin Park <huijin.park@samsung.com> wrote:

> From: "huijin.park" <huijin.park@samsung.com>
> 
> assign of a signed value which has type 'int' to a variable of
> a bigger unsigned integer type 'uint64_t'.

Why are you mentioning u64? AFAICT, the len passed to erase_write() is
always an unsigned int.

> this is ok most of the time, but can lead to unexpectedly large
> resulting value if the original signed value is negative.
> in addtion, the callers of the erase_write() pass the len parameter

  ^In addition,

> as unsigned type.
> 
> Signed-off-by: huijin.park <huijin.park@samsung.com>
> ---
>  drivers/mtd/mtdblock.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
> index a5b1933..b2d5ed1 100644
> --- a/drivers/mtd/mtdblock.c
> +++ b/drivers/mtd/mtdblock.c
> @@ -56,7 +56,7 @@ struct mtdblk_dev {
>   */
>  
>  static int erase_write (struct mtd_info *mtd, unsigned long pos,
> -			int len, const char *buf)
> +			unsigned int len, const char *buf)

The diff looks good, but the commit message is not clear at all. Can
you reword it?

Thanks,

Boris

>  {
>  	struct erase_info erase;
>  	size_t retlen;

Re: [PATCH] mtd: change len type from signed to unsigned type

[Huijin Park]

Hi Boris,

On Wed, Oct 31, 2018 at 11:02 PM Boris Brezillon
<boris.brezillon@bootlin.com> wrote:
>
> Hi Huijin,
>
> On Thu, 23 Aug 2018 04:43:39 -0400
> Huijin Park <huijin.park@samsung.com> wrote:
>
> > From: "huijin.park" <huijin.park@samsung.com>
> >
> > assign of a signed value which has type 'int' to a variable of
> > a bigger unsigned integer type 'uint64_t'.
>
> Why are you mentioning u64? AFAICT, the len passed to erase_write() is
> always an unsigned int.

It's my mistake.
Messages about u64 are not related to this patch.

>
> > this is ok most of the time, but can lead to unexpectedly large
> > resulting value if the original signed value is negative.
> > in addtion, the callers of the erase_write() pass the len parameter
>
>   ^In addition,
>
> > as unsigned type.
> >
> > Signed-off-by: huijin.park <huijin.park@samsung.com>
> > ---
> >  drivers/mtd/mtdblock.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
> > index a5b1933..b2d5ed1 100644
> > --- a/drivers/mtd/mtdblock.c
> > +++ b/drivers/mtd/mtdblock.c
> > @@ -56,7 +56,7 @@ struct mtdblk_dev {
> >   */
> >
> >  static int erase_write (struct mtd_info *mtd, unsigned long pos,
> > -                     int len, const char *buf)
> > +                     unsigned int len, const char *buf)
>
> The diff looks good, but the commit message is not clear at all. Can
> you reword it?
>
> Thanks,
>
> Boris
>
> >  {
> >       struct erase_info erase;
> >       size_t retlen;
>

I will send again patch after reword the commit message.

Thanks & best regards,

Huijin

[PATCH] mtd: change len type from signed to unsigned type

[Huijin Park]

From: "huijin.park" <huijin.park@samsung.com>

This patch casts the "len" parameter to an unsigned int.
The callers of erase_write() pass the "len" parameter as unsigned int.

Signed-off-by: huijin.park <huijin.park@samsung.com>
---
 drivers/mtd/mtdblock.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index a5b1933..b2d5ed1 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -56,7 +56,7 @@ struct mtdblk_dev {
  */
 
 static int erase_write (struct mtd_info *mtd, unsigned long pos,
-			int len, const char *buf)
+			unsigned int len, const char *buf)
 {
 	struct erase_info erase;
 	size_t retlen;
-- 
1.7.9.5