Re: [PATCH RESEND] clk: tegra: bmp: remove kcalloc

[Jerome Brunet <jbrunet@baylibre.com>]

On mar. 29 sept. 2026 at 12:24, Rosen Penev <rosenp@gmail.com> wrote:

> Use a flexible array member to avoid allocating separately.
>
> Use __counted_by for extra runtime analysis.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  drivers/clk/tegra/clk-bpmp.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/clk/tegra/clk-bpmp.c b/drivers/clk/tegra/clk-bpmp.c
> index 067a8555c4e7..15b976162b59 100644
> --- a/drivers/clk/tegra/clk-bpmp.c
> +++ b/drivers/clk/tegra/clk-bpmp.c
> @@ -32,7 +32,7 @@ struct tegra_bpmp_clk {
>  	unsigned int id;
>  
>  	unsigned int num_parents;
> -	unsigned int *parents;
> +	unsigned int parents[] __counted_by(num_parents);
>  };
>  
>  static inline struct tegra_bpmp_clk *to_tegra_bpmp_clk(struct clk_hw *hw)
> @@ -518,20 +518,14 @@ tegra_bpmp_clk_register(struct tegra_bpmp *bpmp,
>  	unsigned int i;
>  	int err;
>  
> -	clk = devm_kzalloc(bpmp->dev, sizeof(*clk), GFP_KERNEL);
> +	clk = devm_kzalloc(bpmp->dev, struct_size(clk, parents, info->num_parents), GFP_KERNEL);
>  	if (!clk)
>  		return ERR_PTR(-ENOMEM);
>  
> +	clk->num_parents = info->num_parents;
>  	clk->id = info->id;
>  	clk->bpmp = bpmp;
>  
> -	clk->parents = devm_kcalloc(bpmp->dev, info->num_parents,
> -				    sizeof(*clk->parents), GFP_KERNEL);
> -	if (!clk->parents)
> -		return ERR_PTR(-ENOMEM);
> -
> -	clk->num_parents = info->num_parents;
> -

What is the benefit of doing this ? It looks like you are just trading
one alloc for another here ?

>  	/* hardware clock initialization */
>  	memset(&init, 0, sizeof(init));
>  	init.name = info->name;
> -- 
> 2.55.0
>

-- 
Jerome