Re: [PATCHv2] dmaengine: dw-axi-dmac: simplify allocation

Frank Li
2026-04-07T02:12:21Z

On Mon, Apr 06, 2026 at 12:44:24PM -0700, Rosen Penev wrote:

Subject need update to

"Use kzalloc_flex() to simplify allocation"

Frank

> Use a flexible array member with kzalloc_flex() to combine allocations.
>
> Add __counted_by for extra runtime analysis.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
> v2: use () for kzalloc_flex in description.
> drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 +-------
> drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 4 ++--
> 2 files changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index 4d53f077e9d2..d3ca202dc478 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -294,15 +294,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
> {
> struct axi_dma_desc *desc;
>
> - desc = kzalloc_obj(*desc, GFP_NOWAIT);
> + desc = kzalloc_flex(*desc, hw_desc, num, GFP_NOWAIT);
> if (!desc)
> return NULL;
>
> - desc->hw_desc = kzalloc_objs(*desc->hw_desc, num, GFP_NOWAIT);
> - if (!desc->hw_desc) {
> - kfree(desc);
> - return NULL;
> - }
> desc->nr_hw_descs = num;
>
> return desc;
> @@ -339,7 +334,6 @@ static void axi_desc_put(struct axi_dma_desc *desc)
> dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
> }
>
> - kfree(desc->hw_desc);
> kfree(desc);
> atomic_sub(descs_put, &chan->descs_allocated);
> dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> index 67cc199e24d1..a04a4e03eb3d 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> @@ -98,14 +98,14 @@ struct axi_dma_hw_desc {
> };
>
> struct axi_dma_desc {
> - struct axi_dma_hw_desc *hw_desc;
> -
> struct virt_dma_desc vd;
> struct axi_dma_chan *chan;
> u32 completed_blocks;
> u32 length;
> u32 period_len;
> u32 nr_hw_descs;
> +
> + struct axi_dma_hw_desc hw_desc[] __counted_by(nr_hw_descs);
> };
>
> struct axi_dma_chan_config {
> --
> 2.53.0
>