On 24 October 2012 09:40, Vinod Koul <vkoul@xxxxxxxxxxxxx> wrote:
> On Fri, 2012-10-05 at 15:47 +0530, Inderpal Singh 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
> For probe, again you have cleaner code by using devm_kzalloc.
>
> On 1, if we use the devm_kzalloc then we don't need to allocate in
> chunks right?
>
Yes, if we use devm_kzalloc we wont have to allocate in chunks.
I will update this patch to use devm_kzalloc and send it again.
>>
>> Signed-off-by: Inderpal Singh <inderpal.singh@xxxxxxxxxx>
>> ---
>> drivers/dma/pl330.c | 35 +++++++++++++++++++++++++----------
>> 1 file changed, 25 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
>> index 10c6b6a..bf71ff7 100644
>> --- a/drivers/dma/pl330.c
>> +++ b/drivers/dma/pl330.c
>> @@ -2541,20 +2541,20 @@ 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;
>> + for (i = 0; i < count; i++) {
>> + desc = kmalloc(sizeof(*desc), flg);
>> + if (!desc)
>> + break;
>> + _init_desc(desc);
>>
>> - spin_lock_irqsave(&pdmac->pool_lock, flags);
>> + 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);
>> - }
>> + list_add_tail(&desc->node, &pdmac->desc_pool);
>>
>> - spin_unlock_irqrestore(&pdmac->pool_lock, flags);
>> + spin_unlock_irqrestore(&pdmac->pool_lock, flags);
>> + }
>>
>> - return count;
>> + return i;
>> }
>>
>> static struct dma_pl330_desc *
>> @@ -2857,6 +2857,7 @@ 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 +2979,12 @@ 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 +3001,7 @@ 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 +3023,13 @@ 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);
>
>
> --
> Vinod Koul
> Intel Corp.
>
Regards,
Inder
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