2022-12-27 18:48:30

by Deepak R Varma

Subject: [PATCH] drm/amd/display: No need for Null pointer check before kfree

kfree() & vfree() internally performs NULL check on the pointer handed
to it and take no action if it indeed is NULL. Hence there is no need
for a pre-check of the memory pointer before handing it to
kfree()/vfree().

Issue reported by ifnullfree.cocci Coccinelle semantic patch script.

Signed-off-by: Deepak R Varma <[email protected]>
---
drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c | 3 +--
drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
index 3ce0ee0d012f..694a9d3d92ae 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
@@ -577,8 +577,7 @@ void dcn3_clk_mgr_construct(

void dcn3_clk_mgr_destroy(struct clk_mgr_internal *clk_mgr)
{
- if (clk_mgr->base.bw_params)
- kfree(clk_mgr->base.bw_params);
+ kfree(clk_mgr->base.bw_params);

if (clk_mgr->wm_range_table)
dm_helpers_free_gpu_mem(clk_mgr->base.ctx, DC_MEM_ALLOC_TYPE_GART,
diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
index 200fcec19186..ba9814f88f48 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
@@ -783,8 +783,7 @@ void dcn32_clk_mgr_construct(

void dcn32_clk_mgr_destroy(struct clk_mgr_internal *clk_mgr)
{
- if (clk_mgr->base.bw_params)
- kfree(clk_mgr->base.bw_params);
+ kfree(clk_mgr->base.bw_params);

if (clk_mgr->wm_range_table)
dm_helpers_free_gpu_mem(clk_mgr->base.ctx, DC_MEM_ALLOC_TYPE_GART,
--
2.34.1

2023-01-07 20:55:07

by Deepak R Varma

Subject: Re: [PATCH] drm/amd/display: No need for Null pointer check before kfree

On Wed, Dec 28, 2022 at 12:09:51AM +0530, Deepak R Varma wrote:
> kfree() & vfree() internally performs NULL check on the pointer handed
> to it and take no action if it indeed is NULL. Hence there is no need
> for a pre-check of the memory pointer before handing it to
> kfree()/vfree().
>
> Issue reported by ifnullfree.cocci Coccinelle semantic patch script.
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---

Hello,
Requesting a review and feedback on this patch proposal.

Thank you,
./drv

2023-01-10 16:19:07

by Rodrigo Siqueira Jordao

Subject: Re: [PATCH] drm/amd/display: No need for Null pointer check before kfree

On 12/27/22 13:39, Deepak R Varma wrote:
> kfree() & vfree() internally performs NULL check on the pointer handed
> to it and take no action if it indeed is NULL. Hence there is no need
> for a pre-check of the memory pointer before handing it to
> kfree()/vfree().
>
> Issue reported by ifnullfree.cocci Coccinelle semantic patch script.
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c | 3 +--
> drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c | 3 +--
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
> index 3ce0ee0d012f..694a9d3d92ae 100644
> --- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
> +++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_clk_mgr.c
> @@ -577,8 +577,7 @@ void dcn3_clk_mgr_construct(
>
> void dcn3_clk_mgr_destroy(struct clk_mgr_internal *clk_mgr)
> {
> - if (clk_mgr->base.bw_params)
> - kfree(clk_mgr->base.bw_params);
> + kfree(clk_mgr->base.bw_params);
>
> if (clk_mgr->wm_range_table)
> dm_helpers_free_gpu_mem(clk_mgr->base.ctx, DC_MEM_ALLOC_TYPE_GART,
> diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
> index 200fcec19186..ba9814f88f48 100644
> --- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
> +++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c
> @@ -783,8 +783,7 @@ void dcn32_clk_mgr_construct(
>
> void dcn32_clk_mgr_destroy(struct clk_mgr_internal *clk_mgr)
> {
> - if (clk_mgr->base.bw_params)
> - kfree(clk_mgr->base.bw_params);
> + kfree(clk_mgr->base.bw_params);
>
> if (clk_mgr->wm_range_table)
> dm_helpers_free_gpu_mem(clk_mgr->base.ctx, DC_MEM_ALLOC_TYPE_GART,
> --
> 2.34.1
>
>
>

Hi,

Reviewed-by: Rodrigo Siqueira <[email protected]>

And applied to amd-staging-drm-next.

Thanks
Siqueira