Re: [PATCH 1/1]drm/gma500: mdfld: Remove unncessary code

Re: [PATCH 1/1]drm/gma500: mdfld: Remove unncessary code

[Maninder Singh]

Hi,

>> -       if (!sender || !data_out || !len_out) {
>> -               DRM_ERROR("Invalid parameters\n");
>> -               return -EINVAL;
>> -       }
>> -
>
>I would prefer to have these kind of checks where it actually matters
>(ie. in __read_panel_data()). The saner thing would be to move the
>dereference until after the check and remove the duplicated check from
>mdfld_dsi_read_mcs(). That would prevent any further need for adding
>additional checks whenever calling __read_panel_data().

Ok agree, But i am thinking whether this initilaization has to be there?
struct drm_device *dev = sender->dev;

Because in function __read_panel_data I saw no usage of this dev struct,
So along with check from mdfld_dsi_read_mcs, can we remove this dev from
__read_panel_data also ? Or i missed something in code?
 
Thanks,
Maninder
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Re: [PATCH 1/1]drm/gma500: mdfld: Remove unncessary code

[Patrik Jakobsson]

On Wed, Jun 24, 2015 at 10:54 AM, Maninder Singh
<maninder1.s@samsung.com> wrote:
> Hi,
>
>>> -       if (!sender || !data_out || !len_out) {
>>> -               DRM_ERROR("Invalid parameters\n");
>>> -               return -EINVAL;
>>> -       }
>>> -
>>
>>I would prefer to have these kind of checks where it actually matters
>>(ie. in __read_panel_data()). The saner thing would be to move the
>>dereference until after the check and remove the duplicated check from
>>mdfld_dsi_read_mcs(). That would prevent any further need for adding
>>additional checks whenever calling __read_panel_data().
>
> Ok agree, But i am thinking whether this initilaization has to be there?
> struct drm_device *dev = sender->dev;
>
> Because in function __read_panel_data I saw no usage of this dev struct,
> So along with check from mdfld_dsi_read_mcs, can we remove this dev from
> __read_panel_data also ? Or i missed something in code?

REG_READ and REG_WRITE macros need the drm device (see psb_drv.h) so
it must stay.

> Thanks,
> Maninder
> ---------
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Re: [PATCH 1/1]drm/gma500: mdfld: Remove unncessary code

[Patrik Jakobsson]

On Wed, Jun 24, 2015 at 9:10 AM, Maninder Singh <maninder1.s@samsung.com> wrote:
> sender is dereferrenced before NULL check
> struct drm_device *dev = sender->dev;
>
> and due to this we get warning during static analysis:
> warn: variable dereferenced before check 'sender'
>
> __read_panel_data Function is called by mdfld_dsi_read_mcs
> and there is a same check, Thus removing the check from
> __read_panel_data.
>
> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
> Reviewed-by: Vaneet Narang <v.narang@samsung.com>
> ---
>  drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c |    5 -----
>  1 files changed, 0 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> index 6b43ae3..d29b881 100644
> --- a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> +++ b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> @@ -525,11 +525,6 @@ static int __read_panel_data(struct mdfld_dsi_pkg_sender *sender, u8 data_type,
>         u32 gen_data_reg;
>         int retry = MDFLD_DSI_READ_MAX_COUNT;
>
> -       if (!sender || !data_out || !len_out) {
> -               DRM_ERROR("Invalid parameters\n");
> -               return -EINVAL;
> -       }
> -

I would prefer to have these kind of checks where it actually matters
(ie. in __read_panel_data()). The saner thing would be to move the
dereference until after the check and remove the duplicated check from
mdfld_dsi_read_mcs(). That would prevent any further need for adding
additional checks whenever calling __read_panel_data().

Cheers
Patrik

>         /**
>          * do reading.
>          * 0) send out generic read request
> --
> 1.7.1
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[PATCH 1/1]drm/gma500: mdfld: Remove unncessary code

[Maninder Singh]

sender is dereferrenced before NULL check
struct drm_device *dev = sender->dev;

and due to this we get warning during static analysis:
warn: variable dereferenced before check 'sender'

__read_panel_data Function is called by mdfld_dsi_read_mcs
and there is a same check, Thus removing the check from
__read_panel_data.

Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Vaneet Narang <v.narang@samsung.com>
---
 drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
index 6b43ae3..d29b881 100644
--- a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
+++ b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
@@ -525,11 +525,6 @@ static int __read_panel_data(struct mdfld_dsi_pkg_sender *sender, u8 data_type,
 	u32 gen_data_reg;
 	int retry = MDFLD_DSI_READ_MAX_COUNT;
 
-	if (!sender || !data_out || !len_out) {
-		DRM_ERROR("Invalid parameters\n");
-		return -EINVAL;
-	}
-
 	/**
 	 * do reading.
 	 * 0) send out generic read request
-- 
1.7.1
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