Re: [PATCH] soc: mediatek: mtk-dvfsrc: use flex array

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

On 3/5/26 08:20, Rosen Penev wrote:
> Simplifies allocation from kzalloc + kcaloc to one allocation.
> 
> Allows extra runtime analysis with __counted_by.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>   drivers/soc/mediatek/mtk-dvfsrc.c | 18 ++++++------------
>   1 file changed, 6 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/soc/mediatek/mtk-dvfsrc.c b/drivers/soc/mediatek/mtk-dvfsrc.c
> index 548a28f50242..48b1fcf3e101 100644
> --- a/drivers/soc/mediatek/mtk-dvfsrc.c
> +++ b/drivers/soc/mediatek/mtk-dvfsrc.c
> @@ -71,8 +71,8 @@ struct dvfsrc_opp {
>   };
>   
>   struct dvfsrc_opp_desc {
> -	const struct dvfsrc_opp *opps;
>   	u32 num_opp;
> +	struct dvfsrc_opp opps[] __counted_by(num_opp);
>   };
>   
>   struct dvfsrc_soc_data;
> @@ -489,7 +489,6 @@ static u32 dvfsrc_get_opp_gear(struct mtk_dvfsrc *dvfsrc, u8 level)
>   
>   static int dvfsrc_get_hw_opps_v4(struct mtk_dvfsrc *dvfsrc)
>   {
> -	struct dvfsrc_opp *dvfsrc_opps;
>   	struct dvfsrc_opp_desc *desc;
>   	u32 num_opps, gear_info;
>   	u8 num_vcore, num_dram;
> @@ -520,24 +519,19 @@ static int dvfsrc_get_hw_opps_v4(struct mtk_dvfsrc *dvfsrc)
>   		 num_opps, num_vcore, num_dram, num_emi);
>   
>   	/* Allocate everything now as anything else after that cannot fail */
> -	desc = devm_kzalloc(dvfsrc->dev, sizeof(*desc), GFP_KERNEL);
> +	desc = devm_kzalloc(dvfsrc->dev, struct_size(desc, opps, num_ops + 1), GFP_KERNEL);

Mmhh... You should really consider building your code before submitting any patches.

-Gustavo

>   	if (!desc)
>   		return -ENOMEM;
>   
> -	dvfsrc_opps = devm_kcalloc(dvfsrc->dev, num_opps + 1,
> -				   sizeof(*dvfsrc_opps), GFP_KERNEL);
> -	if (!dvfsrc_opps)
> -		return -ENOMEM;
> +	desc->num_opp = num_opps + 1;
>   
>   	/* Read the OPP table gear indices */
>   	for (i = 0; i <= num_opps; i++) {
>   		gear_info = dvfsrc_get_opp_gear(dvfsrc, num_opps - i);
> -		dvfsrc_opps[i].vcore_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_VCORE, gear_info);
> -		dvfsrc_opps[i].dram_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_DRAM, gear_info);
> -		dvfsrc_opps[i].emi_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_EMI, gear_info);
> +		desc->opps[i].vcore_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_VCORE, gear_info);
> +		desc->opps[i].dram_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_DRAM, gear_info);
> +		desc->opps[i].emi_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_EMI, gear_info);
>   	};
> -	desc->num_opp = num_opps + 1;
> -	desc->opps = dvfsrc_opps;
>   
>   	/* Assign to main structure now that everything is done! */
>   	dvfsrc->curr_opps = desc;