[PATCH v2 06/64] dmaengine: fsldma: migrate tasklet to dma_chan BH

[PATCH v2 06/64] dmaengine: fsldma: migrate tasklet to dma_chan BH

[Allen Pais]

Replace the per-channel tasklet with the shared dma_chan 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@gmail.com>
---
 drivers/dma/fsldma.c | 10 +++++-----
 drivers/dma/fsldma.h |  1 -
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 22d62d958abd..1cb6ce327078 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -968,18 +968,18 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
 		chan_err(chan, "irq: unhandled sr 0x%08x\n", stat);
 
 	/*
-	 * Schedule the tasklet to handle all cleanup of the current
+	 * Queue the BH worker to handle all cleanup of the current
 	 * transaction. It will start a new transaction if there is
 	 * one pending.
 	 */
-	tasklet_schedule(&chan->tasklet);
+	dma_chan_schedule_bh(&chan->common);
 	chan_dbg(chan, "irq: Exit\n");
 	return IRQ_HANDLED;
 }
 
-static void dma_do_tasklet(struct tasklet_struct *t)
+static void dma_do_tasklet(struct dma_chan *c)
 {
-	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);
+	struct fsldma_chan *chan = to_fsl_chan(c);
 
 	chan_dbg(chan, "tasklet entry\n");
 
@@ -1152,7 +1152,7 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
 	}
 
 	fdev->chan[chan->id] = chan;
-	tasklet_setup(&chan->tasklet, dma_do_tasklet);
+	dma_chan_init_bh(&chan->common, dma_do_tasklet);
 	snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);
 
 	/* Initialize the channel */
diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
index d7b7a3138b85..cab33d010d51 100644
--- a/drivers/dma/fsldma.h
+++ b/drivers/dma/fsldma.h
@@ -173,7 +173,6 @@ struct fsldma_chan {
 	struct device *dev;		/* Channel device */
 	int irq;			/* Channel IRQ */
 	int id;				/* Raw id of this channel */
-	struct tasklet_struct tasklet;
 	u32 feature;
 	bool idle;			/* DMA controller is idle */
 #ifdef CONFIG_PM
-- 
2.43.0

[PATCH v3 06/34] dmaengine: fsldma: migrate tasklet to dmaengine BH

[Allen Pais]

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@gmail.com>
---
 drivers/dma/fsldma.c | 10 +++++-----
 drivers/dma/fsldma.h |  1 -
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 22d62d958abd..f52547611db9 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -968,18 +968,18 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
 		chan_err(chan, "irq: unhandled sr 0x%08x\n", stat);
 
 	/*
-	 * Schedule the tasklet to handle all cleanup of the current
+	 * Queue the BH worker to handle all cleanup of the current
 	 * transaction. It will start a new transaction if there is
 	 * one pending.
 	 */
-	tasklet_schedule(&chan->tasklet);
+	dmaengine_schedule_bh(&chan->common);
 	chan_dbg(chan, "irq: Exit\n");
 	return IRQ_HANDLED;
 }
 
-static void dma_do_tasklet(struct tasklet_struct *t)
+static void dma_do_tasklet(struct dma_chan *c)
 {
-	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);
+	struct fsldma_chan *chan = to_fsl_chan(c);
 
 	chan_dbg(chan, "tasklet entry\n");
 
@@ -1152,7 +1152,7 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
 	}
 
 	fdev->chan[chan->id] = chan;
-	tasklet_setup(&chan->tasklet, dma_do_tasklet);
+	dmaengine_init_bh(&chan->common, dma_do_tasklet);
 	snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);
 
 	/* Initialize the channel */
diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
index d7b7a3138b85..cab33d010d51 100644
--- a/drivers/dma/fsldma.h
+++ b/drivers/dma/fsldma.h
@@ -173,7 +173,6 @@ struct fsldma_chan {
 	struct device *dev;		/* Channel device */
 	int irq;			/* Channel IRQ */
 	int id;				/* Raw id of this channel */
-	struct tasklet_struct tasklet;
 	u32 feature;
 	bool idle;			/* DMA controller is idle */
 #ifdef CONFIG_PM
-- 
2.43.0

Re: [PATCH v3 06/34] dmaengine: fsldma: migrate tasklet to dmaengine BH

[Frank Li]

On Mon, Aug 10, 2026 at 11:09:07AM -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@gmail.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/dma/fsldma.c | 10 +++++-----
>  drivers/dma/fsldma.h |  1 -
>  2 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index 22d62d958abd..f52547611db9 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -968,18 +968,18 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
>  		chan_err(chan, "irq: unhandled sr 0x%08x\n", stat);
>
>  	/*
> -	 * Schedule the tasklet to handle all cleanup of the current
> +	 * Queue the BH worker to handle all cleanup of the current
>  	 * transaction. It will start a new transaction if there is
>  	 * one pending.
>  	 */
> -	tasklet_schedule(&chan->tasklet);
> +	dmaengine_schedule_bh(&chan->common);
>  	chan_dbg(chan, "irq: Exit\n");
>  	return IRQ_HANDLED;
>  }
>
> -static void dma_do_tasklet(struct tasklet_struct *t)
> +static void dma_do_tasklet(struct dma_chan *c)
>  {
> -	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);
> +	struct fsldma_chan *chan = to_fsl_chan(c);
>
>  	chan_dbg(chan, "tasklet entry\n");
>
> @@ -1152,7 +1152,7 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
>  	}
>
>  	fdev->chan[chan->id] = chan;
> -	tasklet_setup(&chan->tasklet, dma_do_tasklet);
> +	dmaengine_init_bh(&chan->common, dma_do_tasklet);
>  	snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);
>
>  	/* Initialize the channel */
> diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
> index d7b7a3138b85..cab33d010d51 100644
> --- a/drivers/dma/fsldma.h
> +++ b/drivers/dma/fsldma.h
> @@ -173,7 +173,6 @@ struct fsldma_chan {
>  	struct device *dev;		/* Channel device */
>  	int irq;			/* Channel IRQ */
>  	int id;				/* Raw id of this channel */
> -	struct tasklet_struct tasklet;
>  	u32 feature;
>  	bool idle;			/* DMA controller is idle */
>  #ifdef CONFIG_PM
> --
> 2.43.0
>