On Mon, Oct 05, 2026 at 12:26:21PM -0700, Rosen Penev wrote:
> Change desc_blocks to a flexible array member so the descriptor and
> its block array are allocated together, removing one allocation and
> its error handling.
>
> Add __counted_by for extra runtime analysis, and set dblk_num right
> after allocation which is already done by kzalloc_flex() for GCC >= 15.
>
> Assisted-by: LLM
> Signed-off-by: Rosen Penev <[email protected]>
> ---

Reviewed-by: Frank Li <[email protected]>

>  drivers/dma/xilinx/xdma.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c
> index 8d4a5d14e8db..16d202722245 100644
> --- a/drivers/dma/xilinx/xdma.c
> +++ b/drivers/dma/xilinx/xdma.c
> @@ -81,7 +81,6 @@ struct xdma_chan {
>   * @vdesc: Virtual DMA descriptor
>   * @chan: DMA channel pointer
>   * @dir: Transferring direction of the request
> - * @desc_blocks: Hardware descriptor blocks
>   * @dblk_num: Number of hardware descriptor blocks
>   * @desc_num: Number of hardware descriptors
>   * @completed_desc_num: Completed hardware descriptors
> @@ -91,12 +90,12 @@ struct xdma_chan {
>   * @period_size: Size of a period in bytes in cyclic transfers
>   * @frames_left: Number of frames left in interleaved DMA transfer
>   * @error: tx error flag
> + * @desc_blocks: Hardware descriptor blocks
>   */
>  struct xdma_desc {
>       struct virt_dma_desc            vdesc;
>       struct xdma_chan                *chan;
>       enum dma_transfer_direction     dir;
> -     struct xdma_desc_block          *desc_blocks;
>       u32                             dblk_num;
>       u32                             desc_num;
>       u32                             completed_desc_num;
> @@ -106,6 +105,7 @@ struct xdma_desc {
>       u32                             period_size;
>       u32                             frames_left;
>       bool                            error;
> +     struct xdma_desc_block          desc_blocks[] __counted_by(dblk_num);
>  };
>
>  #define XDMA_DEV_STATUS_REG_DMA              BIT(0)
> @@ -255,7 +255,6 @@ static void xdma_free_desc(struct virt_dma_desc *vdesc)
>                             sw_desc->desc_blocks[i].virt_addr,
>                             sw_desc->desc_blocks[i].dma_addr);
>       }
> -     kfree(sw_desc->desc_blocks);
>       kfree(sw_desc);
>  }
>
> @@ -276,26 +275,22 @@ xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num, 
> bool cyclic)
>       void *addr;
>       int i, j;
>
> -     sw_desc = kzalloc_obj(*sw_desc, GFP_NOWAIT);
> +     dblk_num = DIV_ROUND_UP(desc_num, XDMA_DESC_ADJACENT);
> +     sw_desc = kzalloc_flex(*sw_desc, desc_blocks, dblk_num, GFP_NOWAIT);
>       if (!sw_desc)
>               return NULL;
>
> +     sw_desc->dblk_num = dblk_num;
>       sw_desc->chan = chan;
>       sw_desc->desc_num = desc_num;
>       sw_desc->cyclic = cyclic;
>       sw_desc->error = false;
> -     dblk_num = DIV_ROUND_UP(desc_num, XDMA_DESC_ADJACENT);
> -     sw_desc->desc_blocks = kzalloc_objs(*sw_desc->desc_blocks, dblk_num,
> -                                         GFP_NOWAIT);
> -     if (!sw_desc->desc_blocks)
> -             goto failed;
>
>       if (cyclic)
>               control = XDMA_DESC_CONTROL_CYCLIC;
>       else
>               control = XDMA_DESC_CONTROL(1, 0);
>
> -     sw_desc->dblk_num = dblk_num;
>       for (i = 0; i < sw_desc->dblk_num; i++) {
>               addr = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &dma_addr);
>               if (!addr)
> --
> 2.56.0
>

Reply via email to