Re: [PATCH] dmaengine: hsu: use kzalloc_flex

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Thu, Mar 26, 2026 at 07:59:43PM -0700, Rosen Penev wrote:
> Simplifies allocations by using a flexible array member in this struct.
> 
> Remove hsu_dma_alloc_desc. It now offers no readability advantages in
> this single usage.
> 
> Add __counted_by to get extra runtime analysis.
> 
> Apply the exact same treatment to struct hsu_dma and devm_kzalloc.

We refer to the functions in the comments and commit messages as func().
Please, update this patch accordingly.

...

>  static void hsu_dma_desc_free(struct virt_dma_desc *vdesc)
>  {
>  	struct hsu_dma_desc *desc = to_hsu_dma_desc(vdesc);
>  
> -	kfree(desc->sg);
>  	kfree(desc);

It can be collapsed to a single line, but for the sake of clarity the above is
okay.

>  }

...

> -	desc = hsu_dma_alloc_desc(sg_len);
> +	desc = kzalloc_flex(*desc, sg, sg_len, GFP_NOWAIT);
>  	if (!desc)
>  		return NULL;
>  
> +	desc->nents = sg_len;
> +

> -	desc->nents = sg_len;
>  	desc->direction = direction;
>  	/* desc->active = 0 by kzalloc */
>  	desc->status = DMA_IN_PROGRESS;

This nents move makes disruption is the field assignment block.
Please, move them all up.

...

>  	void __iomem *addr = chip->regs + chip->offset;
>  	unsigned short i;
>  	int ret;
> +	unsigned short nr_channels;

Preserve reversed xmas tree order.

...

> -	hsu = devm_kzalloc(chip->dev, sizeof(*hsu), GFP_KERNEL);
> +	/* Calculate nr_channels from the IO space length */
> +	nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
> +	hsu = devm_kzalloc(chip->dev, struct_size(hsu, chan, nr_channels), GFP_KERNEL);
>  	if (!hsu)
>  		return -ENOMEM;
>  
> +	hsu->nr_channels = nr_channels;

+ blank line.

>  	chip->hsu = hsu;

-- 
With Best Regards,
Andy Shevchenko