[PATCH] dmaengine: fsl-edma: make channel resource allocation transactional

[PATCH] dmaengine: fsl-edma: make channel resource allocation transactional

[Pengpeng Hou]

Channel allocation ignores a required clock failure and does not reject
a failed TCD DMA-pool allocation before requesting IRQ resources.

Check both prerequisites and unwind only the channel clock that was
enabled by this allocation attempt.

Fixes: 9d831528a656 ("dmaengine: fsl-edma: extract common fsl-edma code (no changes in behavior intended)")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
 drivers/dma/fsl-edma-common.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
index bb7531c456dfa..02b92d1464cca 100644
--- a/drivers/dma/fsl-edma-common.c
+++ b/drivers/dma/fsl-edma-common.c
@@ -844,13 +844,20 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
 	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
 	int ret = 0;
 
-	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
-		clk_prepare_enable(fsl_chan->clk);
+	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK) {
+		ret = clk_prepare_enable(fsl_chan->clk);
+		if (ret)
+			return ret;
+	}
 
 	fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device->dev,
 				fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_TCD64 ?
 				sizeof(struct fsl_edma_hw_tcd64) : sizeof(struct fsl_edma_hw_tcd),
 				32, 0);
+	if (!fsl_chan->tcd_pool) {
+		ret = -ENOMEM;
+		goto err_pool;
+	}
 
 	if (fsl_chan->txirq)
 		ret = request_irq(fsl_chan->txirq, fsl_chan->irq_handler, IRQF_SHARED,
@@ -873,7 +880,9 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
 		free_irq(fsl_chan->txirq, fsl_chan);
 err_txirq:
 	dma_pool_destroy(fsl_chan->tcd_pool);
-	clk_disable_unprepare(fsl_chan->clk);
+err_pool:
+	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
+		clk_disable_unprepare(fsl_chan->clk);
 
 	return ret;
 }

base-commit: 08dbfad3f5040f5bdb6c529da20d6d4e81fefd72
-- 
2.50.1

Re: [PATCH] dmaengine: fsl-edma: make channel resource allocation transactional

[Frank Li]

On Sun, Aug 30, 2026 at 10:09:25PM +0800, Pengpeng Hou wrote:
> Channel allocation ignores a required clock failure and does not reject
> a failed TCD DMA-pool allocation before requesting IRQ resources.
>
> Check both prerequisites and unwind only the channel clock that was
> enabled by this allocation attempt.
>
> Fixes: 9d831528a656 ("dmaengine: fsl-edma: extract common fsl-edma code (no changes in behavior intended)")
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
>  drivers/dma/fsl-edma-common.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
> index bb7531c456dfa..02b92d1464cca 100644
> --- a/drivers/dma/fsl-edma-common.c
> +++ b/drivers/dma/fsl-edma-common.c
> @@ -844,13 +844,20 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
>  	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
>  	int ret = 0;
>
> -	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
> -		clk_prepare_enable(fsl_chan->clk);
> +	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK) {


Actually check is unnecesary because it is no-ops when clock is NULL.

Joy have did some work
at https://patchwork.kernel.org/project/imx/list/?series=1119587

Joy:
	Can you take this patch into your serie to avoid merge conflicts?

Frnak

> +		ret = clk_prepare_enable(fsl_chan->clk);
> +		if (ret)
> +			return ret;
> +	}
>
>  	fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device->dev,
>  				fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_TCD64 ?
>  				sizeof(struct fsl_edma_hw_tcd64) : sizeof(struct fsl_edma_hw_tcd),
>  				32, 0);
> +	if (!fsl_chan->tcd_pool) {
> +		ret = -ENOMEM;
> +		goto err_pool;
> +	}
>
>  	if (fsl_chan->txirq)
>  		ret = request_irq(fsl_chan->txirq, fsl_chan->irq_handler, IRQF_SHARED,
> @@ -873,7 +880,9 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
>  		free_irq(fsl_chan->txirq, fsl_chan);
>  err_txirq:
>  	dma_pool_destroy(fsl_chan->tcd_pool);
> -	clk_disable_unprepare(fsl_chan->clk);
> +err_pool:
> +	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
> +		clk_disable_unprepare(fsl_chan->clk);
>
>  	return ret;
>  }
>
> base-commit: 08dbfad3f5040f5bdb6c529da20d6d4e81fefd72
> --
> 2.50.1
>
>