[PATCH v2 0/2] dmaengine: Add cleanup to simple code

[PATCH v2 0/2] dmaengine: Add cleanup to simple code

[Frank Li]

start_dma()
{
        struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
        ...
        cookie = dmaengine_submit(rx_cmd_desc);
        if (dma_submit_error(cookie))
                return dma_submit_error(cookie);
        ...
        retain_and_null_ptr(rx_cmd_desc);

        return 0;
}

To: Vinod Koul <vkoul@kernel.org>
To: Dong Aisheng <aisheng.dong@nxp.com>
To: Andi Shyti <andi.shyti@kernel.org>
To: Shawn Guo <shawnguo@kernel.org>
To: Sascha Hauer <s.hauer@pengutronix.de>
To: Pengutronix Kernel Team <kernel@pengutronix.de>
To: Fabio Estevam <festevam@gmail.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-i2c@vger.kernel.org
Cc: imx@lists.linux.dev
Cc: linux-arm-kernel@lists.infradead.org
Cc: carlos.song@nxp.com

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Changes in v2:
- fix reduntant empty line remove
- fix goto branch in i2c
- Link to v1: https://lore.kernel.org/r/20251002-dma_chan_free-v1-0-4dbf116c2b19@nxp.com

---
Frank Li (2):
      dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor
      i2c: lpi2c: Use cleanup helper for dma_async_tx_descriptor error handling

 drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
 include/linux/dmaengine.h          |  3 +++
 2 files changed, 6 insertions(+), 8 deletions(-)
---
base-commit: 019ffdd87705bcef1ca5cf9bfdd2b358ce190ab5
change-id: 20251001-dma_chan_free-0392f4004d9e

Best regards,
--
Frank Li <Frank.Li@nxp.com>

[PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Frank Li]

Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
cleanup and simplify error handling.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Check patch report exceed 100 chars, but it's still better put into one
line to keep consistent with other DEFINE_FREE and better readablity

change in v2
- remove surpoiouse remove empty line
---
 include/linux/dmaengine.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -5,6 +5,7 @@
 #ifndef LINUX_DMAENGINE_H
 #define LINUX_DMAENGINE_H
 
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/uio.h>
@@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
 	return desc->desc_free(desc);
 }
 
+DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))
+
 /* --- DMA device --- */
 
 int dma_async_device_register(struct dma_device *device);

-- 
2.34.1

Re: [PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Frank Li]

On Fri, Oct 03, 2025 at 12:26:49PM -0400, Frank Li wrote:
> Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
> cleanup and simplify error handling.
>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---

Vinod Koul:

	Do you have chance to check this one, 3 month passed. Is it missed
at your review queue?

Frank

> Check patch report exceed 100 chars, but it's still better put into one
> line to keep consistent with other DEFINE_FREE and better readablity
>
> change in v2
> - remove surpoiouse remove empty line
> ---
>  include/linux/dmaengine.h | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -5,6 +5,7 @@
>  #ifndef LINUX_DMAENGINE_H
>  #define LINUX_DMAENGINE_H
>
> +#include <linux/cleanup.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/uio.h>
> @@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
>  	return desc->desc_free(desc);
>  }
>
> +DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))
> +
>  /* --- DMA device --- */
>
>  int dma_async_device_register(struct dma_device *device);
>
> --
> 2.34.1
>

Re: [PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Dave Jiang]

On 10/3/25 9:26 AM, Frank Li wrote:
> Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
> cleanup and simplify error handling.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> Check patch report exceed 100 chars, but it's still better put into one
> line to keep consistent with other DEFINE_FREE and better readablity
> 
> change in v2
> - remove surpoiouse remove empty line
> ---
>  include/linux/dmaengine.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -5,6 +5,7 @@
>  #ifndef LINUX_DMAENGINE_H
>  #define LINUX_DMAENGINE_H
>  
> +#include <linux/cleanup.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/uio.h>
> @@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
>  	return desc->desc_free(desc);
>  }
>  
> +DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))

maybe free_dma_async_tx may be clearer as the name vs dma_async_tx_descriptor.

DJ

> +
>  /* --- DMA device --- */
>  
>  int dma_async_device_register(struct dma_device *device);
> 

Re: [PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Frank Li]

On Wed, Dec 03, 2025 at 03:48:41PM -0700, Dave Jiang wrote:
>
>
> On 10/3/25 9:26 AM, Frank Li wrote:
> > Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
> > cleanup and simplify error handling.
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > Check patch report exceed 100 chars, but it's still better put into one
> > line to keep consistent with other DEFINE_FREE and better readablity
> >
> > change in v2
> > - remove surpoiouse remove empty line
> > ---
> >  include/linux/dmaengine.h | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> > index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
> > --- a/include/linux/dmaengine.h
> > +++ b/include/linux/dmaengine.h
> > @@ -5,6 +5,7 @@
> >  #ifndef LINUX_DMAENGINE_H
> >  #define LINUX_DMAENGINE_H
> >
> > +#include <linux/cleanup.h>
> >  #include <linux/device.h>
> >  #include <linux/err.h>
> >  #include <linux/uio.h>
> > @@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
> >  	return desc->desc_free(desc);
> >  }
> >
> > +DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))
>
> maybe free_dma_async_tx may be clearer as the name vs dma_async_tx_descriptor.

If that, 'dmaengine_desc_free' is better because avoid create new name for
it.

Frank
>
> DJ
>
> > +
> >  /* --- DMA device --- */
> >
> >  int dma_async_device_register(struct dma_device *device);
> >
>

Re: [PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Dave Jiang]

On 12/3/25 6:30 PM, Frank Li wrote:
> On Wed, Dec 03, 2025 at 03:48:41PM -0700, Dave Jiang wrote:
>>
>>
>> On 10/3/25 9:26 AM, Frank Li wrote:
>>> Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
>>> cleanup and simplify error handling.
>>>
>>> Signed-off-by: Frank Li <Frank.Li@nxp.com>
>>> ---
>>> Check patch report exceed 100 chars, but it's still better put into one
>>> line to keep consistent with other DEFINE_FREE and better readablity
>>>
>>> change in v2
>>> - remove surpoiouse remove empty line
>>> ---
>>>  include/linux/dmaengine.h | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
>>> index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
>>> --- a/include/linux/dmaengine.h
>>> +++ b/include/linux/dmaengine.h
>>> @@ -5,6 +5,7 @@
>>>  #ifndef LINUX_DMAENGINE_H
>>>  #define LINUX_DMAENGINE_H
>>>
>>> +#include <linux/cleanup.h>
>>>  #include <linux/device.h>
>>>  #include <linux/err.h>
>>>  #include <linux/uio.h>
>>> @@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
>>>  	return desc->desc_free(desc);
>>>  }
>>>
>>> +DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))
>>
>> maybe free_dma_async_tx may be clearer as the name vs dma_async_tx_descriptor.
> 
> If that, 'dmaengine_desc_free' is better because avoid create new name for
> it.

That works too.

> 
> Frank
>>
>> DJ
>>
>>> +
>>>  /* --- DMA device --- */
>>>
>>>  int dma_async_device_register(struct dma_device *device);
>>>
>>
> 

Re: [PATCH v2 1/2] dmaengine: Add cleanup FREE defines for dma_async_tx_descriptor

[Vinod Koul]

On 04-12-25, 08:07, Dave Jiang wrote:
> 
> 
> On 12/3/25 6:30 PM, Frank Li wrote:
> > On Wed, Dec 03, 2025 at 03:48:41PM -0700, Dave Jiang wrote:
> >>
> >>
> >> On 10/3/25 9:26 AM, Frank Li wrote:
> >>> Add cleanup FREE defines for dma_async_tx_descriptor to support automatic
> >>> cleanup and simplify error handling.
> >>>
> >>> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> >>> ---
> >>> Check patch report exceed 100 chars, but it's still better put into one
> >>> line to keep consistent with other DEFINE_FREE and better readablity
> >>>
> >>> change in v2
> >>> - remove surpoiouse remove empty line
> >>> ---
> >>>  include/linux/dmaengine.h | 3 +++
> >>>  1 file changed, 3 insertions(+)
> >>>
> >>> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> >>> index 99efe2b9b4ea9844ca6161208362ef18ef111d96..27fa1646a807c49c781e1bce9e3e7d9a3c66f41d 100644
> >>> --- a/include/linux/dmaengine.h
> >>> +++ b/include/linux/dmaengine.h
> >>> @@ -5,6 +5,7 @@
> >>>  #ifndef LINUX_DMAENGINE_H
> >>>  #define LINUX_DMAENGINE_H
> >>>
> >>> +#include <linux/cleanup.h>
> >>>  #include <linux/device.h>
> >>>  #include <linux/err.h>
> >>>  #include <linux/uio.h>
> >>> @@ -1612,6 +1613,8 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
> >>>  	return desc->desc_free(desc);
> >>>  }
> >>>
> >>> +DEFINE_FREE(dma_async_tx_descriptor, struct dma_async_tx_descriptor *, if (_T) dmaengine_desc_free(_T))
> >>
> >> maybe free_dma_async_tx may be clearer as the name vs dma_async_tx_descriptor.
> > 
> > If that, 'dmaengine_desc_free' is better because avoid create new name for
> > it.
> 
> That works too.

Agree, it is better name

-- 
~Vinod

[PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for dma_async_tx_descriptor error handling

[Frank Li]

Use the cleanup helper to simplify dma_async_tx_descriptor error handling.

No functional change.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
change v2
 need goto unmap buffer.

desc_prepare_err_exit:
        dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
                         dma->rx_cmd_buf_len, DMA_TO_DEVICE);
        return -EINVAL;

submit_err_exit:
        dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
                         dma->rx_cmd_buf_len, DMA_TO_DEVICE);
        dmaengine_desc_free(rx_cmd_desc)

auto cleanup by __free, so whole error path submit_err_exit can be removed
and use desc_prepare_err_exit label.
---
 drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 03b5a7e8c361abe1d75fb4d31f9614bbc6387d93..e31c2d81f59f18a09d34f79896a7fa4bb83c0a12 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -722,7 +722,7 @@ static void lpi2c_dma_callback(void *data)
 
 static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	struct dma_async_tx_descriptor *rx_cmd_desc;
+	struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
 	struct lpi2c_imx_dma *dma = lpi2c_imx->dma;
 	struct dma_chan *txchan = dma->chan_tx;
 	dma_cookie_t cookie;
@@ -746,10 +746,11 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 	cookie = dmaengine_submit(rx_cmd_desc);
 	if (dma_submit_error(cookie)) {
 		dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n");
-		goto submit_err_exit;
+		goto desc_prepare_err_exit;
 	}
 
 	dma_async_issue_pending(txchan);
+	retain_and_null_ptr(rx_cmd_desc);
 
 	return 0;
 
@@ -757,12 +758,6 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
 			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
 	return -EINVAL;
-
-submit_err_exit:
-	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
-			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
-	dmaengine_desc_free(rx_cmd_desc);
-	return -EINVAL;
 }
 
 static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)

-- 
2.34.1

Re: [PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for dma_async_tx_descriptor error handling

[Dave Jiang]

On 10/3/25 9:26 AM, Frank Li wrote:
> Use the cleanup helper to simplify dma_async_tx_descriptor error handling.
> 
> No functional change.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> change v2
>  need goto unmap buffer.
> 
> desc_prepare_err_exit:
>         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>         return -EINVAL;
> 
> submit_err_exit:
>         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>         dmaengine_desc_free(rx_cmd_desc)
> 
> auto cleanup by __free, so whole error path submit_err_exit can be removed
> and use desc_prepare_err_exit label.
> ---
>  drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 03b5a7e8c361abe1d75fb4d31f9614bbc6387d93..e31c2d81f59f18a09d34f79896a7fa4bb83c0a12 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -722,7 +722,7 @@ static void lpi2c_dma_callback(void *data)
>  
>  static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  {
> -	struct dma_async_tx_descriptor *rx_cmd_desc;
> +	struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
>  	struct lpi2c_imx_dma *dma = lpi2c_imx->dma;
>  	struct dma_chan *txchan = dma->chan_tx;
>  	dma_cookie_t cookie;
> @@ -746,10 +746,11 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  	cookie = dmaengine_submit(rx_cmd_desc);
>  	if (dma_submit_error(cookie)) {
>  		dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n");
> -		goto submit_err_exit;
> +		goto desc_prepare_err_exit;

Typically if you are introducing cleanup usage, you will want to remove all the goto usages. Otherwise it gets kinda messy having both styles. Although not sure how to do a cleanup macro with dma_unmap_*. Unless a local one where lpi2c_imx_dma also contains a ptr to the device. Then that may be doable. 

DJ>  	}
>  
>  	dma_async_issue_pending(txchan);
> +	retain_and_null_ptr(rx_cmd_desc);
>  
>  	return 0;
>  
> @@ -757,12 +758,6 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>  	return -EINVAL;
> -
> -submit_err_exit:
> -	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> -			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
> -	dmaengine_desc_free(rx_cmd_desc);
> -	return -EINVAL;
>  }
>  
>  static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)
> 

Re: [PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for dma_async_tx_descriptor error handling

[Frank Li]

On Wed, Dec 03, 2025 at 03:52:09PM -0700, Dave Jiang wrote:
>
>
> On 10/3/25 9:26 AM, Frank Li wrote:
> > Use the cleanup helper to simplify dma_async_tx_descriptor error handling.
> >
> > No functional change.
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > change v2
> >  need goto unmap buffer.
> >
> > desc_prepare_err_exit:
> >         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> >                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
> >         return -EINVAL;
> >
> > submit_err_exit:
> >         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> >                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
> >         dmaengine_desc_free(rx_cmd_desc)
> >
> > auto cleanup by __free, so whole error path submit_err_exit can be removed
> > and use desc_prepare_err_exit label.
> > ---
> >  drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
> >  1 file changed, 3 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
> > index 03b5a7e8c361abe1d75fb4d31f9614bbc6387d93..e31c2d81f59f18a09d34f79896a7fa4bb83c0a12 100644
> > --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> > +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> > @@ -722,7 +722,7 @@ static void lpi2c_dma_callback(void *data)
> >
> >  static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
> >  {
> > -	struct dma_async_tx_descriptor *rx_cmd_desc;
> > +	struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
> >  	struct lpi2c_imx_dma *dma = lpi2c_imx->dma;
> >  	struct dma_chan *txchan = dma->chan_tx;
> >  	dma_cookie_t cookie;
> > @@ -746,10 +746,11 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
> >  	cookie = dmaengine_submit(rx_cmd_desc);
> >  	if (dma_submit_error(cookie)) {
> >  		dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n");
> > -		goto submit_err_exit;
> > +		goto desc_prepare_err_exit;
>
> Typically if you are introducing cleanup usage, you will want to remove all the goto usages. Otherwise it gets kinda messy having both styles. Although not sure how to do a cleanup macro with dma_unmap_*. Unless a local one where lpi2c_imx_dma also contains a ptr to the device. Then that may be doable.

dma_unmap() patch at
https://lore.kernel.org/imx/aPZbuY5bLpkoO2J%2F@lizhi-Precision-Tower-5810/

The first patch need be pickup and dma umap firstly.  Then I can remove all
goto.

Frank

>
> DJ>  	}
> >
> >  	dma_async_issue_pending(txchan);
> > +	retain_and_null_ptr(rx_cmd_desc);
> >
> >  	return 0;
> >
> > @@ -757,12 +758,6 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
> >  	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> >  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
> >  	return -EINVAL;
> > -
> > -submit_err_exit:
> > -	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> > -			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
> > -	dmaengine_desc_free(rx_cmd_desc);
> > -	return -EINVAL;
> >  }
> >
> >  static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)
> >
>

Re: [PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for dma_async_tx_descriptor error handling

[Dave Jiang]

On 12/3/25 6:27 PM, Frank Li wrote:
> On Wed, Dec 03, 2025 at 03:52:09PM -0700, Dave Jiang wrote:
>>
>>
>> On 10/3/25 9:26 AM, Frank Li wrote:
>>> Use the cleanup helper to simplify dma_async_tx_descriptor error handling.
>>>
>>> No functional change.
>>>
>>> Signed-off-by: Frank Li <Frank.Li@nxp.com>
>>> ---
>>> change v2
>>>  need goto unmap buffer.
>>>
>>> desc_prepare_err_exit:
>>>         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>>>                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>>>         return -EINVAL;
>>>
>>> submit_err_exit:
>>>         dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>>>                          dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>>>         dmaengine_desc_free(rx_cmd_desc)
>>>
>>> auto cleanup by __free, so whole error path submit_err_exit can be removed
>>> and use desc_prepare_err_exit label.
>>> ---
>>>  drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
>>>  1 file changed, 3 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
>>> index 03b5a7e8c361abe1d75fb4d31f9614bbc6387d93..e31c2d81f59f18a09d34f79896a7fa4bb83c0a12 100644
>>> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
>>> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
>>> @@ -722,7 +722,7 @@ static void lpi2c_dma_callback(void *data)
>>>
>>>  static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>>>  {
>>> -	struct dma_async_tx_descriptor *rx_cmd_desc;
>>> +	struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
>>>  	struct lpi2c_imx_dma *dma = lpi2c_imx->dma;
>>>  	struct dma_chan *txchan = dma->chan_tx;
>>>  	dma_cookie_t cookie;
>>> @@ -746,10 +746,11 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>>>  	cookie = dmaengine_submit(rx_cmd_desc);
>>>  	if (dma_submit_error(cookie)) {
>>>  		dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n");
>>> -		goto submit_err_exit;
>>> +		goto desc_prepare_err_exit;
>>
>> Typically if you are introducing cleanup usage, you will want to remove all the goto usages. Otherwise it gets kinda messy having both styles. Although not sure how to do a cleanup macro with dma_unmap_*. Unless a local one where lpi2c_imx_dma also contains a ptr to the device. Then that may be doable.
> 
> dma_unmap() patch at
> https://lore.kernel.org/imx/aPZbuY5bLpkoO2J%2F@lizhi-Precision-Tower-5810/
> 
> The first patch need be pickup and dma umap firstly.  Then I can remove all
> goto.

perfect


> 
> Frank
> 
>>
>> DJ>  	}
>>>
>>>  	dma_async_issue_pending(txchan);
>>> +	retain_and_null_ptr(rx_cmd_desc);
>>>
>>>  	return 0;
>>>
>>> @@ -757,12 +758,6 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>>>  	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>>>  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>>>  	return -EINVAL;
>>> -
>>> -submit_err_exit:
>>> -	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
>>> -			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>>> -	dmaengine_desc_free(rx_cmd_desc);
>>> -	return -EINVAL;
>>>  }
>>>
>>>  static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)
>>>
>>
>