diff mbox

[v3,4/8] DMA: Freescale: add fsl_dma_free_descriptor() to reduce code duplication

Message ID 1397113805-24171-5-git-send-email-hongbo.zhang@freescale.com (mailing list archive)
State Superseded
Delegated to: Vinod Koul
Headers show

Commit Message

hongbo.zhang@freescale.com April 10, 2014, 7:10 a.m. UTC 
From: Hongbo Zhang <hongbo.zhang@freescale.com>

There are several places where descriptors are freed using identical code.
This patch puts this code into a function to reduce code duplication.

Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
Signed-off-by: Qiang Liu <qiang.liu@freescale.com>
---
 drivers/dma/fsldma.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

Comments

Andy Shevchenko April 10, 2014, 11:29 a.m. UTC | #1 
On Thu, 2014-04-10 at 15:10 +0800, hongbo.zhang@freescale.com wrote:
> From: Hongbo Zhang <hongbo.zhang@freescale.com>
> 
> There are several places where descriptors are freed using identical code.
> This patch puts this code into a function to reduce code duplication.
> 
> Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
> Signed-off-by: Qiang Liu <qiang.liu@freescale.com>
> ---
>  drivers/dma/fsldma.c |   30 ++++++++++++++++++------------
>  1 file changed, 18 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index b71cc04..b5a0ffa 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -418,6 +418,19 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
>  }
>  
>  /**
> + * fsl_dma_free_descriptor - Free descriptor from channel's DMA pool.
> + * @chan : Freescale DMA channel
> + * @desc: descriptor to be freed
> + */
> +static void fsl_dma_free_descriptor(struct fsldma_chan *chan,
> +		struct fsl_desc_sw *desc)
> +{
> +	list_del(&desc->node);
> +	chan_dbg(chan, "LD %p free\n", desc);
> +	dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
> +}
> +
> +/**
>   * fsl_dma_alloc_descriptor - Allocate descriptor from channel's DMA pool.
>   * @chan : Freescale DMA channel
>   *
> @@ -489,11 +502,8 @@ static void fsldma_free_desc_list(struct fsldma_chan *chan,
>  {
>  	struct fsl_desc_sw *desc, *_desc;
>  
> -	list_for_each_entry_safe(desc, _desc, list, node) {
> -		list_del(&desc->node);
> -		chan_dbg(chan, "LD %p free\n", desc);
> -		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
> -	}
> +	list_for_each_entry_safe(desc, _desc, list, node)
> +		fsl_dma_free_descriptor(chan, desc);
>  }
>  
>  static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
> @@ -501,11 +511,8 @@ static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
>  {
>  	struct fsl_desc_sw *desc, *_desc;
>  
> -	list_for_each_entry_safe_reverse(desc, _desc, list, node) {
> -		list_del(&desc->node);
> -		chan_dbg(chan, "LD %p free\n", desc);
> -		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
> -	}
> +	list_for_each_entry_safe_reverse(desc, _desc, list, node)
> +		fsl_dma_free_descriptor(chan, desc);
>  }
>  
>  /**
> @@ -819,8 +826,7 @@ static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
>  	dma_run_dependencies(txd);
>  
>  	dma_descriptor_unmap(txd);
> -	chan_dbg(chan, "LD %p free\n", desc);
> -	dma_pool_free(chan->desc_pool, desc, txd->phys);
> +	fsl_dma_free_descriptor(chan, desc);

Here is no list_del() call since it's been called in dma_do_tasklet().
What will be the result of double list_del() against the same node?

>  }
>  
>  /**
hongbo.zhang@freescale.com April 11, 2014, 8:14 a.m. UTC | #2 
On 04/10/2014 07:29 PM, Andy Shevchenko wrote:
> On Thu, 2014-04-10 at 15:10 +0800, hongbo.zhang@freescale.com wrote:
>> From: Hongbo Zhang <hongbo.zhang@freescale.com>
>>
>> There are several places where descriptors are freed using identical code.
>> This patch puts this code into a function to reduce code duplication.
>>
>> Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
>> Signed-off-by: Qiang Liu <qiang.liu@freescale.com>
>> ---
>>   drivers/dma/fsldma.c |   30 ++++++++++++++++++------------
>>   1 file changed, 18 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
>> index b71cc04..b5a0ffa 100644
>> --- a/drivers/dma/fsldma.c
>> +++ b/drivers/dma/fsldma.c
>> @@ -418,6 +418,19 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
>>   }
>>   
>>   /**
>> + * fsl_dma_free_descriptor - Free descriptor from channel's DMA pool.
>> + * @chan : Freescale DMA channel
>> + * @desc: descriptor to be freed
>> + */
>> +static void fsl_dma_free_descriptor(struct fsldma_chan *chan,
>> +		struct fsl_desc_sw *desc)
>> +{
>> +	list_del(&desc->node);
>> +	chan_dbg(chan, "LD %p free\n", desc);
>> +	dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
>> +}
>> +
>> +/**
>>    * fsl_dma_alloc_descriptor - Allocate descriptor from channel's DMA pool.
>>    * @chan : Freescale DMA channel
>>    *
>> @@ -489,11 +502,8 @@ static void fsldma_free_desc_list(struct fsldma_chan *chan,
>>   {
>>   	struct fsl_desc_sw *desc, *_desc;
>>   
>> -	list_for_each_entry_safe(desc, _desc, list, node) {
>> -		list_del(&desc->node);
>> -		chan_dbg(chan, "LD %p free\n", desc);
>> -		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
>> -	}
>> +	list_for_each_entry_safe(desc, _desc, list, node)
>> +		fsl_dma_free_descriptor(chan, desc);
>>   }
>>   
>>   static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
>> @@ -501,11 +511,8 @@ static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
>>   {
>>   	struct fsl_desc_sw *desc, *_desc;
>>   
>> -	list_for_each_entry_safe_reverse(desc, _desc, list, node) {
>> -		list_del(&desc->node);
>> -		chan_dbg(chan, "LD %p free\n", desc);
>> -		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
>> -	}
>> +	list_for_each_entry_safe_reverse(desc, _desc, list, node)
>> +		fsl_dma_free_descriptor(chan, desc);
>>   }
>>   
>>   /**
>> @@ -819,8 +826,7 @@ static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
>>   	dma_run_dependencies(txd);
>>   
>>   	dma_descriptor_unmap(txd);
>> -	chan_dbg(chan, "LD %p free\n", desc);
>> -	dma_pool_free(chan->desc_pool, desc, txd->phys);
>> +	fsl_dma_free_descriptor(chan, desc);
> Here is no list_del() call since it's been called in dma_do_tasklet().
> What will be the result of double list_del() against the same node?

Not clear with your point.
This patch is only introducing a common fsl_dma_free_descriptor() to 
reduce code duplication. And later in the patch 6/8 the 
fsldma_cleanup_descriptor() is replaced by fsldma_cleanup_descriptorS().

>>   }
>>   
>>   /**
>



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Andy Shevchenko April 14, 2014, 1:40 p.m. UTC | #3 
On Fri, 2014-04-11 at 16:14 +0800, Hongbo Zhang wrote:
> On 04/10/2014 07:29 PM, Andy Shevchenko wrote:
> > On Thu, 2014-04-10 at 15:10 +0800, hongbo.zhang@freescale.com wrote:

[]

> >> @@ -819,8 +826,7 @@ static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
> >>   	dma_run_dependencies(txd);
> >>   
> >>   	dma_descriptor_unmap(txd);
> >> -	chan_dbg(chan, "LD %p free\n", desc);
> >> -	dma_pool_free(chan->desc_pool, desc, txd->phys);
> >> +	fsl_dma_free_descriptor(chan, desc);
> > Here is no list_del() call since it's been called in dma_do_tasklet().
> > What will be the result of double list_del() against the same node?
> 
> Not clear with your point.
> This patch is only introducing a common fsl_dma_free_descriptor() to 
> reduce code duplication. And later in the patch 6/8 the 
> fsldma_cleanup_descriptor() is replaced by fsldma_cleanup_descriptorS().

In the last case you could have a broken kernel which will fails on
double list_del(). I think it's better to leave this one untouched and
you may remove it later.

Or move this patch after you have removed that lines.
hongbo.zhang@freescale.com April 18, 2014, 4:09 a.m. UTC | #4 
On 04/14/2014 09:40 PM, Andy Shevchenko wrote:
> On Fri, 2014-04-11 at 16:14 +0800, Hongbo Zhang wrote:
>> On 04/10/2014 07:29 PM, Andy Shevchenko wrote:
>>> On Thu, 2014-04-10 at 15:10 +0800, hongbo.zhang@freescale.com wrote:
> []
>
>>>> @@ -819,8 +826,7 @@ static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
>>>>    	dma_run_dependencies(txd);
>>>>    
>>>>    	dma_descriptor_unmap(txd);
>>>> -	chan_dbg(chan, "LD %p free\n", desc);
>>>> -	dma_pool_free(chan->desc_pool, desc, txd->phys);
>>>> +	fsl_dma_free_descriptor(chan, desc);
>>> Here is no list_del() call since it's been called in dma_do_tasklet().
>>> What will be the result of double list_del() against the same node?
>> Not clear with your point.
>> This patch is only introducing a common fsl_dma_free_descriptor() to
>> reduce code duplication. And later in the patch 6/8 the
>> fsldma_cleanup_descriptor() is replaced by fsldma_cleanup_descriptorS().
> In the last case you could have a broken kernel which will fails on
> double list_del(). I think it's better to leave this one untouched and
> you may remove it later.
>
> Or move this patch after you have removed that lines.
>

Good catch, thank you Andy.
Yes I prefer to leave this untouched and handle it later.




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diff mbox

Patch

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index b71cc04..b5a0ffa 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -418,6 +418,19 @@  static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 }
 
 /**
+ * fsl_dma_free_descriptor - Free descriptor from channel's DMA pool.
+ * @chan : Freescale DMA channel
+ * @desc: descriptor to be freed
+ */
+static void fsl_dma_free_descriptor(struct fsldma_chan *chan,
+		struct fsl_desc_sw *desc)
+{
+	list_del(&desc->node);
+	chan_dbg(chan, "LD %p free\n", desc);
+	dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
+}
+
+/**
  * fsl_dma_alloc_descriptor - Allocate descriptor from channel's DMA pool.
  * @chan : Freescale DMA channel
  *
@@ -489,11 +502,8 @@  static void fsldma_free_desc_list(struct fsldma_chan *chan,
 {
 	struct fsl_desc_sw *desc, *_desc;
 
-	list_for_each_entry_safe(desc, _desc, list, node) {
-		list_del(&desc->node);
-		chan_dbg(chan, "LD %p free\n", desc);
-		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
-	}
+	list_for_each_entry_safe(desc, _desc, list, node)
+		fsl_dma_free_descriptor(chan, desc);
 }
 
 static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
@@ -501,11 +511,8 @@  static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
 {
 	struct fsl_desc_sw *desc, *_desc;
 
-	list_for_each_entry_safe_reverse(desc, _desc, list, node) {
-		list_del(&desc->node);
-		chan_dbg(chan, "LD %p free\n", desc);
-		dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
-	}
+	list_for_each_entry_safe_reverse(desc, _desc, list, node)
+		fsl_dma_free_descriptor(chan, desc);
 }
 
 /**
@@ -819,8 +826,7 @@  static void fsldma_cleanup_descriptor(struct fsldma_chan *chan,
 	dma_run_dependencies(txd);
 
 	dma_descriptor_unmap(txd);
-	chan_dbg(chan, "LD %p free\n", desc);
-	dma_pool_free(chan->desc_pool, desc, txd->phys);
+	fsl_dma_free_descriptor(chan, desc);
 }
 
 /**