Re: [PATCH] mmc: wmt-sdmmc: release DMA descriptors after stopping the host

[Alexey Charkov]

On Mon, Oct 19, 2026 at 5:53 PM Guanxin Li <bruceli20040604@xxxxxxxxx> wrote:
>
> wmt_mci_remove() currently frees the DMA descriptor buffer before calling
> mmc_remove_host() and freeing the controller IRQs. The controller may still
> be using the descriptors, and an interrupt handler may still access them
> during this window.
>
> Stop the MMC host and free both IRQs before releasing the DMA buffer to
> prevent DMA or interrupt accesses to the freed memory during device removal.
>
> Signed-off-by: Guanxin Li <bruceli20040604@xxxxxxxxx>
> ---
>  drivers/mmc/host/wmt-sdmmc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/wmt-sdmmc.c b/drivers/mmc/host/wmt-sdmmc.c
> index 489daee4f4fc..c44befabc909 100644
> --- a/drivers/mmc/host/wmt-sdmmc.c
> +++ b/drivers/mmc/host/wmt-sdmmc.c
> @@ -896,14 +896,14 @@ static void wmt_mci_remove(struct platform_device *pdev)
>         writeb(0xFF, priv->sdmmc_base + SDMMC_STS1);
>
>         /* release the dma buffers */
> -       dma_free_coherent(&pdev->dev, priv->mmc->max_blk_count * 16,
> -                         priv->dma_desc_buffer, priv->dma_desc_device_addr);
> +

If you are moving the function call, please move the comment too (or
better yet delete it altogether, as it doesn't add much information).
And no double blank lines please.

>         mmc_remove_host(mmc);
>
>         free_irq(priv->irq_regular, priv);
>         free_irq(priv->irq_dma, priv);
> -
> +       dma_free_coherent(&pdev->dev, priv->mmc->max_blk_count * 16,
> +                         priv->dma_desc_buffer, priv->dma_desc_device_addr);
>         iounmap(priv->sdmmc_base);
>
>         clk_disable_unprepare(priv->clk_sdmmc);

Other than the above,

Reviewed-by: Alexey Charkov <alchark@xxxxxxxxx>

Best regards,
Alexey