kernel/dma: export dma_alloc_from_contiguous to modules
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Message ID 20190711053343.28873-1-miles.chen@mediatek.com
State New
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  • kernel/dma: export dma_alloc_from_contiguous to modules
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Commit Message

Miles Chen July 11, 2019, 5:33 a.m. UTC
From: Miles Chen <miles.chen@mediatek.com>

This change exports dma_alloc_from_contiguous and
dma_release_from_contiguous to modules.

Currently, we can add a reserve a memory node in dts files, make
it a CMA memory by setting compatible = "shared-dma-pool",
and setup the dev->cma_area by using of_reserved_mem_device_init_by_idx().

Export dma_alloc_from_contiguous and dma_release_from_contiguous, so we
can allocate/free from/to dev->cma_area in kernel modules.

Signed-off-by: Miles Chen <miles.chen@mediatek.com>
---
 kernel/dma/contiguous.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Robin Murphy July 11, 2019, 8:50 a.m. UTC | #1
On 11/07/2019 06:33, miles.chen@mediatek.com wrote:
> From: Miles Chen <miles.chen@mediatek.com>
> 
> This change exports dma_alloc_from_contiguous and
> dma_release_from_contiguous to modules.
> 
> Currently, we can add a reserve a memory node in dts files, make
> it a CMA memory by setting compatible = "shared-dma-pool",
> and setup the dev->cma_area by using of_reserved_mem_device_init_by_idx().
> 
> Export dma_alloc_from_contiguous and dma_release_from_contiguous, so we
> can allocate/free from/to dev->cma_area in kernel modules.

As far as I understand, this was never intended for drivers to call 
directly. If a device has its own private CMA area, then regular 
dma_alloc_attrs() should allocate from that automatically; if that's not 
happening already, then there's a bug somewhere.

Robin.

> Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> ---
>   kernel/dma/contiguous.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index b2a87905846d..d5920bdedc77 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -197,6 +197,7 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
>   
>   	return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
>   }
> +EXPORT_SYMBOL_GPL(dma_alloc_from_contiguous);
>   
>   /**
>    * dma_release_from_contiguous() - release allocated pages
> @@ -213,6 +214,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   {
>   	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> +EXPORT_SYMBOL_GPL(dma_release_from_contiguous);
>   
>   /*
>    * Support for reserved memory regions defined in device tree
>
Christoph Hellwig July 11, 2019, 10:03 a.m. UTC | #2
On Thu, Jul 11, 2019 at 09:50:58AM +0100, Robin Murphy wrote:
> On 11/07/2019 06:33, miles.chen@mediatek.com wrote:
>> From: Miles Chen <miles.chen@mediatek.com>
>>
>> This change exports dma_alloc_from_contiguous and
>> dma_release_from_contiguous to modules.
>>
>> Currently, we can add a reserve a memory node in dts files, make
>> it a CMA memory by setting compatible = "shared-dma-pool",
>> and setup the dev->cma_area by using of_reserved_mem_device_init_by_idx().
>>
>> Export dma_alloc_from_contiguous and dma_release_from_contiguous, so we
>> can allocate/free from/to dev->cma_area in kernel modules.
>
> As far as I understand, this was never intended for drivers to call 
> directly. If a device has its own private CMA area, then regular 
> dma_alloc_attrs() should allocate from that automatically; if that's not 
> happening already, then there's a bug somewhere.

Agreed.
Miles Chen July 11, 2019, 10:44 a.m. UTC | #3
On Thu, 2019-07-11 at 09:50 +0100, Robin Murphy wrote:
> On 11/07/2019 06:33, miles.chen@mediatek.com wrote:
> > From: Miles Chen <miles.chen@mediatek.com>
> > 
> > This change exports dma_alloc_from_contiguous and
> > dma_release_from_contiguous to modules.
> > 
> > Currently, we can add a reserve a memory node in dts files, make
> > it a CMA memory by setting compatible = "shared-dma-pool",
> > and setup the dev->cma_area by using of_reserved_mem_device_init_by_idx().
> > 
> > Export dma_alloc_from_contiguous and dma_release_from_contiguous, so we
> > can allocate/free from/to dev->cma_area in kernel modules.
> 
> As far as I understand, this was never intended for drivers to call 
> directly. If a device has its own private CMA area, then regular 
> dma_alloc_attrs() should allocate from that automatically; if that's not 
> happening already, then there's a bug somewhere.
> 
> Robin.

Thanks for your comment. 
After using dma_direct_ops, dma_alloc_attrs() works fine now.

Miles

> 
> > Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> > ---
> >   kernel/dma/contiguous.c | 2 ++
> >   1 file changed, 2 insertions(+)
> > 
> > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> > index b2a87905846d..d5920bdedc77 100644
> > --- a/kernel/dma/contiguous.c
> > +++ b/kernel/dma/contiguous.c
> > @@ -197,6 +197,7 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
> >   
> >   	return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
> >   }
> > +EXPORT_SYMBOL_GPL(dma_alloc_from_contiguous);
> >   
> >   /**
> >    * dma_release_from_contiguous() - release allocated pages
> > @@ -213,6 +214,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
> >   {
> >   	return cma_release(dev_get_cma_area(dev), pages, count);
> >   }
> > +EXPORT_SYMBOL_GPL(dma_release_from_contiguous);
> >   
> >   /*
> >    * Support for reserved memory regions defined in device tree
> >

Patch
diff mbox series

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index b2a87905846d..d5920bdedc77 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -197,6 +197,7 @@  struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
 
 	return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
 }
+EXPORT_SYMBOL_GPL(dma_alloc_from_contiguous);
 
 /**
  * dma_release_from_contiguous() - release allocated pages
@@ -213,6 +214,7 @@  bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 {
 	return cma_release(dev_get_cma_area(dev), pages, count);
 }
+EXPORT_SYMBOL_GPL(dma_release_from_contiguous);
 
 /*
  * Support for reserved memory regions defined in device tree