diff mbox

[2/3] DMA: PL330: Change allocation method to properly free DMA descriptors

Message ID 1348563456-30569-3-git-send-email-inderpal.singh@linaro.org
State New
Headers show

Commit Message

Inderpal Singh Sept. 25, 2012, 8:57 a.m. UTC
In probe, memory for multiple DMA descriptors were being allocated at once
and then it was being split and added into DMA pool one by one. The address
of this memory allocation is not being saved anywhere. To free this memory,
the address is required. Initially the first node of the pool will be
pointed by this address but as we use this pool the descs will shuffle and
hence we will lose the track of the address.

This patch does following:

1. Allocates DMA descs one by one and then adds them to pool so that all
   descs can be fetched and memory freed one by one. This way runtime
   added descs can also be freed.
2. Free DMA descs in case of error in probe and in module's remove function

Signed-off-by: Inderpal Singh <inderpal.singh@linaro.org>
---
 drivers/dma/pl330.c |   28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

Comments

Jassi Brar Sept. 25, 2012, 1:09 p.m. UTC | #1
On Tue, Sep 25, 2012 at 2:27 PM, Inderpal Singh
<inderpal.singh@linaro.org> wrote:
> In probe, memory for multiple DMA descriptors were being allocated at once
> and then it was being split and added into DMA pool one by one. The address
> of this memory allocation is not being saved anywhere. To free this memory,
> the address is required. Initially the first node of the pool will be
> pointed by this address but as we use this pool the descs will shuffle and
> hence we will lose the track of the address.
>
> This patch does following:
>
> 1. Allocates DMA descs one by one and then adds them to pool so that all
>    descs can be fetched and memory freed one by one. This way runtime
>    added descs can also be freed.
> 2. Free DMA descs in case of error in probe and in module's remove function
>
> Signed-off-by: Inderpal Singh <inderpal.singh@linaro.org>
> ---
>  drivers/dma/pl330.c |   28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index 10c6b6a..04d83e6 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -2541,20 +2541,19 @@ static int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count)
>         if (!pdmac)
>                 return 0;
>
> -       desc = kmalloc(count * sizeof(*desc), flg);
> -       if (!desc)
> -               return 0;
> -
>         spin_lock_irqsave(&pdmac->pool_lock, flags);
>
>         for (i = 0; i < count; i++) {
> -               _init_desc(&desc[i]);
> -               list_add_tail(&desc[i].node, &pdmac->desc_pool);
> +               desc = kmalloc(sizeof(*desc), flg);
> +               if (!desc)
> +                       break;
> +               _init_desc(desc);
> +               list_add_tail(&desc->node, &pdmac->desc_pool);
>         }
>
>         spin_unlock_irqrestore(&pdmac->pool_lock, flags);
>
> -       return count;
> +       return i;
>  }
>
OK, but the kmalloc shouldn't be done with irqs disabled. Please
protect only the list_add_tail()

thanks.

>  static struct dma_pl330_desc *
> @@ -2857,6 +2856,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>         struct dma_pl330_platdata *pdat;
>         struct dma_pl330_dmac *pdmac;
>         struct dma_pl330_chan *pch;
> +       struct dma_pl330_desc *desc;
>         struct pl330_info *pi;
>         struct dma_device *pd;
>         struct resource *res;
> @@ -2978,6 +2978,12 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>  probe_err5:
>         kfree(pdmac->peripherals);
>  probe_err4:
> +       while (!list_empty(&pdmac->desc_pool)) {
> +               desc = list_entry(pdmac->desc_pool.next,
> +                               struct dma_pl330_desc, node);
> +               list_del(&desc->node);
> +               kfree(desc);
> +       }
>         pl330_del(pi);
>  probe_err3:
>         free_irq(irq, pi);
> @@ -2994,6 +3000,7 @@ static int __devexit pl330_remove(struct amba_device *adev)
>  {
>         struct dma_pl330_dmac *pdmac = amba_get_drvdata(adev);
>         struct dma_pl330_chan *pch, *_p;
> +       struct dma_pl330_desc *desc;
>         struct pl330_info *pi;
>         struct resource *res;
>         int irq;
> @@ -3015,6 +3022,13 @@ static int __devexit pl330_remove(struct amba_device *adev)
>                 pl330_free_chan_resources(&pch->chan);
>         }
>
> +       while (!list_empty(&pdmac->desc_pool)) {
> +               desc = list_entry(pdmac->desc_pool.next,
> +                               struct dma_pl330_desc, node);
> +               list_del(&desc->node);
> +               kfree(desc);
> +       }
> +
>         pi = &pdmac->pif;
>
>         pl330_del(pi);
> --
> 1.7.9.5
>
Inderpal Singh Sept. 25, 2012, 3:26 p.m. UTC | #2
On 25 September 2012 18:39, Jassi Brar <jassisinghbrar@gmail.com> wrote:
> On Tue, Sep 25, 2012 at 2:27 PM, Inderpal Singh
> <inderpal.singh@linaro.org> wrote:
>> In probe, memory for multiple DMA descriptors were being allocated at once
>> and then it was being split and added into DMA pool one by one. The address
>> of this memory allocation is not being saved anywhere. To free this memory,
>> the address is required. Initially the first node of the pool will be
>> pointed by this address but as we use this pool the descs will shuffle and
>> hence we will lose the track of the address.
>>
>> This patch does following:
>>
>> 1. Allocates DMA descs one by one and then adds them to pool so that all
>>    descs can be fetched and memory freed one by one. This way runtime
>>    added descs can also be freed.
>> 2. Free DMA descs in case of error in probe and in module's remove function
>>
>> Signed-off-by: Inderpal Singh <inderpal.singh@linaro.org>
>> ---
>>  drivers/dma/pl330.c |   28 +++++++++++++++++++++-------
>>  1 file changed, 21 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
>> index 10c6b6a..04d83e6 100644
>> --- a/drivers/dma/pl330.c
>> +++ b/drivers/dma/pl330.c
>> @@ -2541,20 +2541,19 @@ static int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count)
>>         if (!pdmac)
>>                 return 0;
>>
>> -       desc = kmalloc(count * sizeof(*desc), flg);
>> -       if (!desc)
>> -               return 0;
>> -
>>         spin_lock_irqsave(&pdmac->pool_lock, flags);
>>
>>         for (i = 0; i < count; i++) {
>> -               _init_desc(&desc[i]);
>> -               list_add_tail(&desc[i].node, &pdmac->desc_pool);
>> +               desc = kmalloc(sizeof(*desc), flg);
>> +               if (!desc)
>> +                       break;
>> +               _init_desc(desc);
>> +               list_add_tail(&desc->node, &pdmac->desc_pool);
>>         }
>>
>>         spin_unlock_irqrestore(&pdmac->pool_lock, flags);
>>
>> -       return count;
>> +       return i;
>>  }
>>
> OK, but the kmalloc shouldn't be done with irqs disabled. Please
> protect only the list_add_tail()
>
Yes, I missed it. I will update and send it again.

Thanks,
Inder

> thanks.
>
>>  static struct dma_pl330_desc *
>> @@ -2857,6 +2856,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>>         struct dma_pl330_platdata *pdat;
>>         struct dma_pl330_dmac *pdmac;
>>         struct dma_pl330_chan *pch;
>> +       struct dma_pl330_desc *desc;
>>         struct pl330_info *pi;
>>         struct dma_device *pd;
>>         struct resource *res;
>> @@ -2978,6 +2978,12 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>>  probe_err5:
>>         kfree(pdmac->peripherals);
>>  probe_err4:
>> +       while (!list_empty(&pdmac->desc_pool)) {
>> +               desc = list_entry(pdmac->desc_pool.next,
>> +                               struct dma_pl330_desc, node);
>> +               list_del(&desc->node);
>> +               kfree(desc);
>> +       }
>>         pl330_del(pi);
>>  probe_err3:
>>         free_irq(irq, pi);
>> @@ -2994,6 +3000,7 @@ static int __devexit pl330_remove(struct amba_device *adev)
>>  {
>>         struct dma_pl330_dmac *pdmac = amba_get_drvdata(adev);
>>         struct dma_pl330_chan *pch, *_p;
>> +       struct dma_pl330_desc *desc;
>>         struct pl330_info *pi;
>>         struct resource *res;
>>         int irq;
>> @@ -3015,6 +3022,13 @@ static int __devexit pl330_remove(struct amba_device *adev)
>>                 pl330_free_chan_resources(&pch->chan);
>>         }
>>
>> +       while (!list_empty(&pdmac->desc_pool)) {
>> +               desc = list_entry(pdmac->desc_pool.next,
>> +                               struct dma_pl330_desc, node);
>> +               list_del(&desc->node);
>> +               kfree(desc);
>> +       }
>> +
>>         pi = &pdmac->pif;
>>
>>         pl330_del(pi);
>> --
>> 1.7.9.5
>>
diff mbox

Patch

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 10c6b6a..04d83e6 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2541,20 +2541,19 @@  static int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count)
 	if (!pdmac)
 		return 0;
 
-	desc = kmalloc(count * sizeof(*desc), flg);
-	if (!desc)
-		return 0;
-
 	spin_lock_irqsave(&pdmac->pool_lock, flags);
 
 	for (i = 0; i < count; i++) {
-		_init_desc(&desc[i]);
-		list_add_tail(&desc[i].node, &pdmac->desc_pool);
+		desc = kmalloc(sizeof(*desc), flg);
+		if (!desc)
+			break;
+		_init_desc(desc);
+		list_add_tail(&desc->node, &pdmac->desc_pool);
 	}
 
 	spin_unlock_irqrestore(&pdmac->pool_lock, flags);
 
-	return count;
+	return i;
 }
 
 static struct dma_pl330_desc *
@@ -2857,6 +2856,7 @@  pl330_probe(struct amba_device *adev, const struct amba_id *id)
 	struct dma_pl330_platdata *pdat;
 	struct dma_pl330_dmac *pdmac;
 	struct dma_pl330_chan *pch;
+	struct dma_pl330_desc *desc;
 	struct pl330_info *pi;
 	struct dma_device *pd;
 	struct resource *res;
@@ -2978,6 +2978,12 @@  pl330_probe(struct amba_device *adev, const struct amba_id *id)
 probe_err5:
 	kfree(pdmac->peripherals);
 probe_err4:
+	while (!list_empty(&pdmac->desc_pool)) {
+		desc = list_entry(pdmac->desc_pool.next,
+				struct dma_pl330_desc, node);
+		list_del(&desc->node);
+		kfree(desc);
+	}
 	pl330_del(pi);
 probe_err3:
 	free_irq(irq, pi);
@@ -2994,6 +3000,7 @@  static int __devexit pl330_remove(struct amba_device *adev)
 {
 	struct dma_pl330_dmac *pdmac = amba_get_drvdata(adev);
 	struct dma_pl330_chan *pch, *_p;
+	struct dma_pl330_desc *desc;
 	struct pl330_info *pi;
 	struct resource *res;
 	int irq;
@@ -3015,6 +3022,13 @@  static int __devexit pl330_remove(struct amba_device *adev)
 		pl330_free_chan_resources(&pch->chan);
 	}
 
+	while (!list_empty(&pdmac->desc_pool)) {
+		desc = list_entry(pdmac->desc_pool.next,
+				struct dma_pl330_desc, node);
+		list_del(&desc->node);
+		kfree(desc);
+	}
+
 	pi = &pdmac->pif;
 
 	pl330_del(pi);