Re: [PATCHv2 1/3] clk: samsung: use kzalloc_flex

[Brian Masney <bmasney@redhat.com>]

Hi Rosen,

On Wed, May 06, 2026 at 04:38:31PM -0700, Rosen Penev wrote:
> Simplify allocation by using kzalloc_flex with a flexible array member
> to combine allocations. samsung_clk_alloc_reg_dump is no longer needed
> for this struct but is needed elsewhere.
> 
> Add __counted_by for extra runtime analysis. Move counting variable
> assignment after kzalloc_flex which does the same with GCC 15 and above.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  drivers/clk/samsung/clk.c | 11 ++++++-----
>  drivers/clk/samsung/clk.h |  2 +-
>  2 files changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clk/samsung/clk.c b/drivers/clk/samsung/clk.c
> index 91e5cdbc79d7..2895c77534ae 100644
> --- a/drivers/clk/samsung/clk.c
> +++ b/drivers/clk/samsung/clk.c
> @@ -430,21 +430,22 @@ void samsung_clk_extended_sleep_init(void __iomem *reg_base,
>  			unsigned long nr_rsuspend)
>  {
>  	struct samsung_clock_reg_cache *reg_cache;
> +	int i;
>  
> -	reg_cache = kzalloc_obj(struct samsung_clock_reg_cache);
> +	reg_cache = kzalloc_flex(*reg_cache, rdump, nr_rdump);
>  	if (!reg_cache)
>  		panic("could not allocate register reg_cache.\n");
> -	reg_cache->rdump = samsung_clk_alloc_reg_dump(rdump, nr_rdump);

samsung_clk_alloc_reg_dump() is used in three other places. Is it
possible to convert those 3 places in a similar fashion so that this
function can be dropped?

>  
> -	if (!reg_cache->rdump)
> -		panic("could not allocate register dump storage.\n");
> +	reg_cache->rd_num = nr_rdump;
> +
> +	for (i = 0; i < nr_rdump; ++i)
> +		reg_cache->rdump[i].offset = rdump[i];
>  
>  	if (list_empty(&clock_reg_cache_list))
>  		register_syscore(&samsung_clk_syscore);
>  
>  	reg_cache->reg_base = reg_base;
>  	reg_cache->sysreg = sysreg;
> -	reg_cache->rd_num = nr_rdump;
>  	reg_cache->rsuspend = rsuspend;
>  	reg_cache->rsuspend_num = nr_rsuspend;
>  	list_add_tail(&reg_cache->node, &clock_reg_cache_list);
> diff --git a/drivers/clk/samsung/clk.h b/drivers/clk/samsung/clk.h
> index b1192ca03db5..098f27a6290d 100644
> --- a/drivers/clk/samsung/clk.h
> +++ b/drivers/clk/samsung/clk.h
> @@ -324,10 +324,10 @@ struct samsung_clock_reg_cache {
>  	struct list_head node;
>  	void __iomem *reg_base;
>  	struct regmap *sysreg;
> -	struct samsung_clk_reg_dump *rdump;
>  	unsigned int rd_num;
>  	const struct samsung_clk_reg_dump *rsuspend;
>  	unsigned int rsuspend_num;
> +	struct samsung_clk_reg_dump rdump[] __counted_by(rd_num);

Personally I think the rd_num should be above rdump so that they are
together.

Brian