Re: [PATCH v3 05/34] dmaengine: ep93xx: hook callbacks via dmaengine BH

[Frank Li]

On Mon, Aug 10, 2026 at 11:09:06AM -0700, Allen Pais wrote:
> Replace the per-channel tasklet with the shared dmaengine BH helper.
> The handler continues to run in softirq context while dmaengine owns
> the common scheduling and teardown mechanism.
>
> Signed-off-by: Allen Pais <allen.lkml@xxxxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

>  drivers/dma/ep93xx_dma.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
> index 311e55a97ba9..d79e278fb7ba 100644
> --- a/drivers/dma/ep93xx_dma.c
> +++ b/drivers/dma/ep93xx_dma.c
> @@ -167,7 +167,6 @@ struct ep93xx_dma_chan_cfg {
>   * @dma_cfg: channel number, direction
>   * @irq: interrupt number of the channel
>   * @clk: clock used by this channel
> - * @tasklet: channel specific tasklet used for callbacks
>   * @lock: lock protecting the fields following
>   * @flags: flags for the channel
>   * @buffer: which buffer to use next (0/1)
> @@ -196,7 +195,6 @@ struct ep93xx_dma_chan {
>  	struct ep93xx_dma_chan_cfg	dma_cfg;
>  	int				irq;
>  	struct clk			*clk;
> -	struct tasklet_struct		tasklet;
>  	/* protects the fields following */
>  	spinlock_t			lock;
>  	unsigned long			flags;
> @@ -801,9 +799,9 @@ static void ep93xx_dma_advance_work(struct ep93xx_dma_chan *edmac)
>  	spin_unlock_irqrestore(&edmac->lock, flags);
>  }
>
> -static void ep93xx_dma_tasklet(struct tasklet_struct *t)
> +static void ep93xx_dma_tasklet(struct dma_chan *chan)
>  {
> -	struct ep93xx_dma_chan *edmac = from_tasklet(edmac, t, tasklet);
> +	struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
>  	struct ep93xx_dma_desc *desc, *d;
>  	struct dmaengine_desc_callback cb;
>  	LIST_HEAD(list);
> @@ -858,12 +856,12 @@ static irqreturn_t ep93xx_dma_interrupt(int irq, void *dev_id)
>  	switch (edmac->edma->hw_interrupt(edmac)) {
>  	case INTERRUPT_DONE:
>  		desc->complete = true;
> -		tasklet_schedule(&edmac->tasklet);
> +		dmaengine_schedule_bh(&edmac->chan);
>  		break;
>
>  	case INTERRUPT_NEXT_BUFFER:
>  		if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags))
> -			tasklet_schedule(&edmac->tasklet);
> +			dmaengine_schedule_bh(&edmac->chan);
>  		break;
>
>  	default:
> @@ -1420,7 +1418,7 @@ static struct ep93xx_dma_engine *ep93xx_dma_of_probe(struct platform_device *pde
>  		INIT_LIST_HEAD(&edmac->active);
>  		INIT_LIST_HEAD(&edmac->queue);
>  		INIT_LIST_HEAD(&edmac->free_list);
> -		tasklet_setup(&edmac->tasklet, ep93xx_dma_tasklet);
> +		dmaengine_init_bh(&edmac->chan, ep93xx_dma_tasklet);
>
>  		list_add_tail(&edmac->chan.device_node,
>  			      &dma_dev->channels);
> --
> 2.43.0
>