[PATCH] staging: greybus: power_supply: Use struct_size() helper

[PATCH] staging: greybus: power_supply: Use struct_size() helper

[Gustavo A. R. Silva]

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace code of the following form:

sizeof(*resp) + props_count * sizeof(struct gb_power_supply_props_desc)

with:

struct_size(resp, props, props_count)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/staging/greybus/power_supply.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/greybus/power_supply.c b/drivers/staging/greybus/power_supply.c
index 0529e5628c24..40cc2d462ba0 100644
--- a/drivers/staging/greybus/power_supply.c
+++ b/drivers/staging/greybus/power_supply.c
@@ -520,8 +520,8 @@ static int gb_power_supply_prop_descriptors_get(struct gb_power_supply *gbpsy)
 
 	op = gb_operation_create(connection,
 				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
-				 sizeof(req), sizeof(*resp) + props_count *
-				 sizeof(struct gb_power_supply_props_desc),
+				 sizeof(req),
+				 struct_size(resp, props, props_count),
 				 GFP_KERNEL);
 	if (!op)
 		return -ENOMEM;
-- 
2.21.0

Re: [PATCH] staging: greybus: power_supply: Use struct_size() helper

[Johan Hovold]

On Wed, Apr 03, 2019 at 03:58:01PM -0500, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
> 
> So, replace code of the following form:
> 
> sizeof(*resp) + props_count * sizeof(struct gb_power_supply_props_desc)
> 
> with:
> 
> struct_size(resp, props, props_count)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  drivers/staging/greybus/power_supply.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/greybus/power_supply.c b/drivers/staging/greybus/power_supply.c
> index 0529e5628c24..40cc2d462ba0 100644
> --- a/drivers/staging/greybus/power_supply.c
> +++ b/drivers/staging/greybus/power_supply.c
> @@ -520,8 +520,8 @@ static int gb_power_supply_prop_descriptors_get(struct gb_power_supply *gbpsy)
>  
>  	op = gb_operation_create(connection,
>  				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
> -				 sizeof(req), sizeof(*resp) + props_count *

This patch looks good, but I noticed a bug here in the current code,
which should be fixed before applying this clean up.

sizeof(req) should have been sizeof(*req) above.

> -				 sizeof(struct gb_power_supply_props_desc),
> +				 sizeof(req),
> +				 struct_size(resp, props, props_count),
>  				 GFP_KERNEL);
>  	if (!op)
>  		return -ENOMEM;

I've just submitted a fix (and CCed you as well). 

Would you mind respinning on top of that one?

Thanks,
Johan

Re: [PATCH] staging: greybus: power_supply: Use struct_size() helper

[Rui Miguel Silva]

Hi Gustavo,
Thanks a lot for the patch.

On Wed 03 Apr 2019 at 21:58, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded 
> version
> in order to avoid any potential type mistakes, in particular in 
> the
> context in which this code is being used.
>
> So, replace code of the following form:
>
> sizeof(*resp) + props_count * sizeof(struct 
> gb_power_supply_props_desc)
>
> with:
>
> struct_size(resp, props, props_count)
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

What are the odds of 2 people changing same code in greybus in
the same day :).

But it happened, so as Johan asked please rebase on top of his
patch. that would be great.

---
Cheers,
	Rui

> ---
>  drivers/staging/greybus/power_supply.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/greybus/power_supply.c 
> b/drivers/staging/greybus/power_supply.c
> index 0529e5628c24..40cc2d462ba0 100644
> --- a/drivers/staging/greybus/power_supply.c
> +++ b/drivers/staging/greybus/power_supply.c
> @@ -520,8 +520,8 @@ static int 
> gb_power_supply_prop_descriptors_get(struct gb_power_supply 
> *gbpsy)
>  
>  	op = gb_operation_create(connection,
>  				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
> -				 sizeof(req), sizeof(*resp) + 
> props_count *
> -				 sizeof(struct 
> gb_power_supply_props_desc),
> +				 sizeof(req),
> +				 struct_size(resp, props, 
> props_count),
>  				 GFP_KERNEL);
>  	if (!op)
>  		return -ENOMEM;

Re: [PATCH] staging: greybus: power_supply: Use struct_size() helper

[Johan Hovold]

On Thu, Apr 04, 2019 at 08:09:51AM +0100, Rui Miguel Silva wrote:
> Hi Gustavo,
> Thanks a lot for the patch.
> 
> On Wed 03 Apr 2019 at 21:58, Gustavo A. R. Silva wrote:
> > Make use of the struct_size() helper instead of an open-coded 
> > version
> > in order to avoid any potential type mistakes, in particular in 
> > the
> > context in which this code is being used.
> >
> > So, replace code of the following form:
> >
> > sizeof(*resp) + props_count * sizeof(struct 
> > gb_power_supply_props_desc)
> >
> > with:
> >
> > struct_size(resp, props, props_count)
> >
> > This code was detected with the help of Coccinelle.
> >
> > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> 
> What are the odds of 2 people changing same code in greybus in
> the same day :).

Well, I only noticed the bug in the current code, when reviewing
Gustavo's diff. ;)

Johan

Re: [PATCH] staging: greybus: power_supply: Use struct_size() helper

[Gustavo A. R. Silva]

Hi Johan,

On 4/4/19 1:57 AM, Johan Hovold wrote:
> 
> This patch looks good, but I noticed a bug here in the current code,
> which should be fixed before applying this clean up.
> 
> sizeof(req) should have been sizeof(*req) above.
> 

Good catch.

>> -				 sizeof(struct gb_power_supply_props_desc),
>> +				 sizeof(req),
>> +				 struct_size(resp, props, props_count),
>>  				 GFP_KERNEL);
>>  	if (!op)
>>  		return -ENOMEM;
> 
> I've just submitted a fix (and CCed you as well). 
> 
> Would you mind respinning on top of that one?
> 

Yep. I'll send v2 shortly.

Thanks
--
Gustavo

Re: [PATCH] staging: greybus: power_supply: Use struct_size() helper

[Gustavo A. R. Silva]

Johan,

On 4/4/19 2:24 AM, Johan Hovold wrote:
> On Thu, Apr 04, 2019 at 08:09:51AM +0100, Rui Miguel Silva wrote:
>> Hi Gustavo,
>> Thanks a lot for the patch.
>>
>> On Wed 03 Apr 2019 at 21:58, Gustavo A. R. Silva wrote:
>>> Make use of the struct_size() helper instead of an open-coded 
>>> version
>>> in order to avoid any potential type mistakes, in particular in 
>>> the
>>> context in which this code is being used.
>>>
>>> So, replace code of the following form:
>>>
>>> sizeof(*resp) + props_count * sizeof(struct 
>>> gb_power_supply_props_desc)
>>>
>>> with:
>>>
>>> struct_size(resp, props, props_count)
>>>
>>> This code was detected with the help of Coccinelle.
>>>
>>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>
>> What are the odds of 2 people changing same code in greybus in
>> the same day :).
> 
> Well, I only noticed the bug in the current code, when reviewing
> Gustavo's diff. ;)
> 

Apparently, your patch hasn't been applied to any tree yet.  So, I'll
wait for it to be applied before sending v2.

Thanks
--
Gustavo