Re: [PATCH 03/17] dmaengine: dw-edma: Terminate STOP requests without callbacks

[Frank Li]

On Tue, Jun 16, 2026 at 12:40:57AM +0900, Koichiro Den wrote:
> The STOP request path handles device_terminate_all(). The DMA Engine
> client documentation says in the "Terminate APIs" section of
> Documentation/driver-api/dmaengine/client.rst:
>
>   "No callback functions will be called for any incomplete transfers."
>
> dw-edma used vchan_cookie_complete() for a stopped descriptor. This
> queues the descriptor on the completed list and schedules its callback.
> A late callback after dmaengine_terminate_sync() can dereference
> callback state, such as a request object, that the client has already
> freed.
>
> Move stopped descriptors to the terminated list. Complete the cookie
> before doing so, so cookie polling observes that the transfer is no
> longer in flight, but do not schedule the completion callback. Add a
> synchronize callback so virt-dma can release terminated descriptors.
>
> Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
> Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
> ---
>  drivers/dma/dw-edma/dw-edma-core.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index d99b6256660a..bedaee6d30ab 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -106,6 +106,13 @@ static int dw_edma_start_transfer(struct dw_edma_chan *chan)
>  	return 1;
>  }
>
> +static void dw_edma_terminate_vdesc(struct virt_dma_desc *vd)
> +{
> +	list_del(&vd->node);
> +	dma_cookie_complete(&vd->tx);
> +	vchan_terminate_vdesc(vd);

Is it vchan_terminate_vdesc() missing call dma_cookie_complete()?

> +}
> +
>  static void dw_edma_device_caps(struct dma_chan *dchan,
>  				struct dma_slave_caps *caps)
>  {
> @@ -537,8 +544,7 @@ static void dw_edma_done_interrupt(struct dw_edma_chan *chan)
>  			break;
>
>  		case EDMA_REQ_STOP:
> -			list_del(&vd->node);
> -			vchan_cookie_complete(vd);
> +			dw_edma_terminate_vdesc(vd);
>  			chan->request = EDMA_REQ_NONE;
>  			chan->status = EDMA_ST_IDLE;
>  			break;
> @@ -610,6 +616,13 @@ static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
>  	return 0;
>  }
>
> +static void dw_edma_device_synchronize(struct dma_chan *dchan)
> +{
> +	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> +
> +	vchan_synchronize(&chan->vc);
> +}
> +
>  static void dw_edma_free_chan_resources(struct dma_chan *dchan)
>  {
>  	unsigned long timeout = jiffies + msecs_to_jiffies(5000);
> @@ -723,6 +736,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
>  	dma->device_pause = dw_edma_device_pause;
>  	dma->device_resume = dw_edma_device_resume;
>  	dma->device_terminate_all = dw_edma_device_terminate_all;
> +	dma->device_synchronize = dw_edma_device_synchronize;

Can we provide generally call back like, vchan_synchroniz_dmachan(), or
change existing vchan_synchronize() to by using struct dma_chan *dchan.

avoid duplicate it every dmaegine drivers.

Frank

>  	dma->device_issue_pending = dw_edma_device_issue_pending;
>  	dma->device_tx_status = dw_edma_device_tx_status;
>  	dma->device_prep_slave_sg_config = dw_edma_device_prep_slave_sg_config;
> --
> 2.51.0
>