[PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Gustavo A. R. Silva]

Fix boolean expression by using logical AND operator '&&'
instead of bitwise operator '&'.

This issue was detected with the help of Coccinelle.

Fixes: 6d04ee9dc101 ("drm/amd/display: Restructuring and cleaning up DML")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
index c2037daa8e66..d341b69fdc1a 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
@@ -881,7 +881,7 @@ static void get_surf_rq_param(
 	/* the dpte_group_bytes is reduced for the specific case of vertical
 	 * access of a tile surface that has dpte request of 8x1 ptes.
 	 */
-	if (!surf_linear & (log2_dpte_req_height_ptes == 0) & surf_vert) /*reduced, in this case, will have page fault within a group */
+	if (!surf_linear && (log2_dpte_req_height_ptes == 0) && surf_vert) /*reduced, in this case, will have page fault within a group */
 		rq_sizing_param->dpte_group_bytes = 512;
 	else
 		/*full size */
-- 
2.20.1

Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Wentland, Harry]

On 2019-01-03 2:48 p.m., Gustavo A. R. Silva wrote:
> Fix boolean expression by using logical AND operator '&&'
> instead of bitwise operator '&'.
> 
> This issue was detected with the help of Coccinelle.
> 
> Fixes: 6d04ee9dc101 ("drm/amd/display: Restructuring and cleaning up DML")
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Reviewed-by: Harry Wentland <harry.wentland@amd.com>

and applied.

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> index c2037daa8e66..d341b69fdc1a 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> +++ b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> @@ -881,7 +881,7 @@ static void get_surf_rq_param(
>  	/* the dpte_group_bytes is reduced for the specific case of vertical
>  	 * access of a tile surface that has dpte request of 8x1 ptes.
>  	 */
> -	if (!surf_linear & (log2_dpte_req_height_ptes == 0) & surf_vert) /*reduced, in this case, will have page fault within a group */
> +	if (!surf_linear && (log2_dpte_req_height_ptes == 0) && surf_vert) /*reduced, in this case, will have page fault within a group */
>  		rq_sizing_param->dpte_group_bytes = 512;
>  	else
>  		/*full size */
> 
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Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Wentland, Harry]

On 2019-01-03 2:48 p.m., Gustavo A. R. Silva wrote:
> Fix boolean expression by using logical AND operator '&&'
> instead of bitwise operator '&'.
> 
> This issue was detected with the help of Coccinelle.
> 
> Fixes: 6d04ee9dc101 ("drm/amd/display: Restructuring and cleaning up DML")
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Reviewed-by: Harry Wentland <harry.wentland@amd.com>

and applied.

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> index c2037daa8e66..d341b69fdc1a 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> +++ b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
> @@ -881,7 +881,7 @@ static void get_surf_rq_param(
>  	/* the dpte_group_bytes is reduced for the specific case of vertical
>  	 * access of a tile surface that has dpte request of 8x1 ptes.
>  	 */
> -	if (!surf_linear & (log2_dpte_req_height_ptes == 0) & surf_vert) /*reduced, in this case, will have page fault within a group */
> +	if (!surf_linear && (log2_dpte_req_height_ptes == 0) && surf_vert) /*reduced, in this case, will have page fault within a group */
>  		rq_sizing_param->dpte_group_bytes = 512;
>  	else
>  		/*full size */
> 

Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Gustavo A. R. Silva]

On 1/3/19 3:11 PM, Wentland, Harry wrote:
> On 2019-01-03 2:48 p.m., Gustavo A. R. Silva wrote:
>> Fix boolean expression by using logical AND operator '&&'
>> instead of bitwise operator '&'.
>>
>> This issue was detected with the help of Coccinelle.
>>
>> Fixes: 6d04ee9dc101 ("drm/amd/display: Restructuring and cleaning up DML")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> 
> Reviewed-by: Harry Wentland <harry.wentland@amd.com>
> 
> and applied.
> 

Thanks, Harry.

--
Gustavo

Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Gustavo A. R. Silva]

Hi Harry,

I noticed this patch is already in mainline, but the stable tag
was removed.  What is the reason for that if this bug is present
in stable?

Thanks
--
Gustavo

On 1/3/19 3:11 PM, Wentland, Harry wrote:
> On 2019-01-03 2:48 p.m., Gustavo A. R. Silva wrote:
>> Fix boolean expression by using logical AND operator '&&'
>> instead of bitwise operator '&'.
>>
>> This issue was detected with the help of Coccinelle.
>>
>> Fixes: 6d04ee9dc101 ("drm/amd/display: Restructuring and cleaning up DML")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> 
> Reviewed-by: Harry Wentland <harry.wentland@amd.com>
> 
> and applied.
> 
> Harry
> 
>> ---
>>  drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
>> index c2037daa8e66..d341b69fdc1a 100644
>> --- a/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
>> +++ b/drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.c
>> @@ -881,7 +881,7 @@ static void get_surf_rq_param(
>>  	/* the dpte_group_bytes is reduced for the specific case of vertical
>>  	 * access of a tile surface that has dpte request of 8x1 ptes.
>>  	 */
>> -	if (!surf_linear & (log2_dpte_req_height_ptes == 0) & surf_vert) /*reduced, in this case, will have page fault within a group */
>> +	if (!surf_linear && (log2_dpte_req_height_ptes == 0) && surf_vert) /*reduced, in this case, will have page fault within a group */
>>  		rq_sizing_param->dpte_group_bytes = 512;
>>  	else
>>  		/*full size */
>>

Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Joe Perches]

On Thu, 2019-03-21 at 22:10 -0500, Gustavo A. R. Silva wrote:
> Hi Harry,
> 
> I noticed this patch is already in mainline, but the stable tag
> was removed.  What is the reason for that if this bug is present
> in stable?

It's not a bug, it's just a style issue and
the && use in some compilers it may be slower.

bool when set is 1.

Re: [PATCH] drm/amd/display: Fix boolean expression in get_surf_rq_param

[Gustavo A. R. Silva]

On 3/21/19 10:14 PM, Joe Perches wrote:
> On Thu, 2019-03-21 at 22:10 -0500, Gustavo A. R. Silva wrote:
>> Hi Harry,
>>
>> I noticed this patch is already in mainline, but the stable tag
>> was removed.  What is the reason for that if this bug is present
>> in stable?
> 
> It's not a bug, it's just a style issue and
> the && use in some compilers it may be slower.
> 

You're right. What might be a bug in some cases
is the other way around.

Thanks, Joe.

--
Gustavo