media: verisilicon: Remove unnecessary memset() after dma_alloc_coherent

[PATCH] media: verisilicon: Remove unnecessary memset() after dma_alloc_coherent

Posted by Luo Qiu 1 week, 1 day ago

dma_alloc_coherent() already returns zeroed memory, so the subsequent
memset(0) calls are redundant.

Signed-off-by: Luo Qiu <luoqiu@kylinsec.com.cn>
---
 drivers/media/platform/verisilicon/hantro_vp9.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/media/platform/verisilicon/hantro_vp9.c b/drivers/media/platform/verisilicon/hantro_vp9.c
index 566cd376c097..607d618e8f4a 100644
--- a/drivers/media/platform/verisilicon/hantro_vp9.c
+++ b/drivers/media/platform/verisilicon/hantro_vp9.c
@@ -187,7 +187,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
 		return -ENOMEM;
 
 	tile_edge->size = size;
-	memset(tile_edge->cpu, 0, size);
 
 	size = hantro_vp9_segment_map_size(max_width, max_height);
 	vp9_dec->segment_map_size = size;
@@ -198,7 +197,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
 		goto err_segment_map;
 
 	segment_map->size = size;
-	memset(segment_map->cpu, 0, size);
 
 	size = hantro_vp9_prob_tab_size();
 	vp9_dec->ctx_counters_offset = size;
@@ -211,7 +209,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
 		goto err_misc;
 
 	misc->size = size;
-	memset(misc->cpu, 0, size);
 
 	init_v4l2_vp9_count_tbl(ctx);
 
-- 
2.53.0

Re: [PATCH] media: verisilicon: Remove unnecessary memset() after dma_alloc_coherent

Posted by Nicolas Dufresne 1 week, 1 day ago

Le mercredi 25 mars 2026 à 13:00 +0800, Luo Qiu a écrit :
> dma_alloc_coherent() already returns zeroed memory, so the subsequent
> memset(0) calls are redundant.

I don't think this statement is actually true, or at least not for all
architectures, and not without an explicit GFP_ZERO flag.

Nicolas

> 
> Signed-off-by: Luo Qiu <luoqiu@kylinsec.com.cn>
> ---
>  drivers/media/platform/verisilicon/hantro_vp9.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/media/platform/verisilicon/hantro_vp9.c b/drivers/media/platform/verisilicon/hantro_vp9.c
> index 566cd376c097..607d618e8f4a 100644
> --- a/drivers/media/platform/verisilicon/hantro_vp9.c
> +++ b/drivers/media/platform/verisilicon/hantro_vp9.c
> @@ -187,7 +187,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
>  		return -ENOMEM;
>  
>  	tile_edge->size = size;
> -	memset(tile_edge->cpu, 0, size);
>  
>  	size = hantro_vp9_segment_map_size(max_width, max_height);
>  	vp9_dec->segment_map_size = size;
> @@ -198,7 +197,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
>  		goto err_segment_map;
>  
>  	segment_map->size = size;
> -	memset(segment_map->cpu, 0, size);
>  
>  	size = hantro_vp9_prob_tab_size();
>  	vp9_dec->ctx_counters_offset = size;
> @@ -211,7 +209,6 @@ int hantro_vp9_dec_init(struct hantro_ctx *ctx)
>  		goto err_misc;
>  
>  	misc->size = size;
> -	memset(misc->cpu, 0, size);
>  
>  	init_v4l2_vp9_count_tbl(ctx);
>