Re: [dpdk-dev] [PATCH v25 1/6] dmadev: introduce DMA device library

[Thomas Monjalon <thomas@monjalon.net>]

13/10/2021 02:21, fengchengwen:
> On 2021/10/13 3:09, Thomas Monjalon wrote:
> > 11/10/2021 09:33, Chengwen Feng:
> >> +static void
> >> +dma_release(struct rte_dma_dev *dev)
> >> +{
> >> +	rte_free(dev->dev_private);
> >> +	memset(dev, 0, sizeof(struct rte_dma_dev));
> >> +}
[...]
> >> +int
> >> +rte_dma_pmd_release(const char *name)
> >> +{
> >> +	struct rte_dma_dev *dev;
> >> +
> >> +	if (dma_check_name(name) != 0)
> >> +		return -EINVAL;
> >> +
> >> +	dev = dma_find_by_name(name);
> >> +	if (dev == NULL)
> >> +		return -EINVAL;
> >> +
> >> +	dma_release(dev);
> >> +	return 0;
> >> +}
> > 
> > Trying to understand the logic of creation/destroy.
> > skeldma_probe
> > \-> skeldma_create
> >     \-> rte_dma_pmd_allocate
> >         \-> dma_allocate
> >             \-> dma_data_prepare
> >                 \-> dma_dev_data_prepare
> > skeldma_remove
> > \-> skeldma_destroy
> >     \-> rte_dma_pmd_release
> >         \-> dma_release
> 
> This patch only provide device allocate function, the 2st patch provide extra logic:
> 
> 	diff --git a/lib/dmadev/rte_dmadev.c b/lib/dmadev/rte_dmadev.c
> 	index 42a4693bd9..a6a5680d2b 100644
> 	--- a/lib/dmadev/rte_dmadev.c
> 	+++ b/lib/dmadev/rte_dmadev.c
> 	@@ -201,6 +201,9 @@ rte_dma_pmd_release(const char *name)
> 	        if (dev == NULL)
>         	        return -EINVAL;
> 
> 	+       if (dev->state == RTE_DMA_DEV_READY)
> 	+               return rte_dma_close(dev->dev_id);
> 	+
>         	dma_release(dev);
> 	        return 0;
> 	 }
> 
> So the skeldma remove will be:
> 
>  skeldma_remove
>  \-> skeldma_destroy
>      \-> rte_dma_pmd_release
>          \-> rte_dma_close
>              \-> dma_release

OK, in this case, no need to dma_release from rte_dma_pmd_release,
because it is already called from rte_dma_close.