[3/3] videobuf2: replace a layering violation with dma_map_resource
diff mbox series

Message ID 20190111181731.11782-4-hch@lst.de
State New
Headers show
Series
  • [1/3] dma-mapping: remove the default map_resource implementation
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Commit Message

hch@lst.de Jan. 11, 2019, 6:17 p.m. UTC
vb2_dc_get_userptr pokes into arm direct mapping details to get the
resemblance of a dma address for a a physical address that does is
not backed by a page struct.  Not only is this not portable to other
architectures with dma direct mapping offsets, but also not to uses
of IOMMUs of any kind.  Switch to the proper dma_map_resource /
dma_unmap_resource interface instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 .../common/videobuf2/videobuf2-dma-contig.c   | 41 ++++---------------
 1 file changed, 9 insertions(+), 32 deletions(-)

Comments

Mauro Carvalho Chehab Jan. 11, 2019, 7:54 p.m. UTC | #1
Em Fri, 11 Jan 2019 19:17:31 +0100
Christoph Hellwig <hch@lst.de> escreveu:

> vb2_dc_get_userptr pokes into arm direct mapping details to get the
> resemblance of a dma address for a a physical address that does is
> not backed by a page struct.  Not only is this not portable to other
> architectures with dma direct mapping offsets, but also not to uses
> of IOMMUs of any kind.  Switch to the proper dma_map_resource /
> dma_unmap_resource interface instead.

Makes sense to me. I'm assuming that you'll be pushing it together
with other mm patches, so:

Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  .../common/videobuf2/videobuf2-dma-contig.c   | 41 ++++---------------
>  1 file changed, 9 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index aff0ab7bf83d..82389aead6ed 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -439,42 +439,14 @@ static void vb2_dc_put_userptr(void *buf_priv)
>  				set_page_dirty_lock(pages[i]);
>  		sg_free_table(sgt);
>  		kfree(sgt);
> +	} else {
> +		dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
> +				   buf->dma_dir, 0);
>  	}
>  	vb2_destroy_framevec(buf->vec);
>  	kfree(buf);
>  }
>  
> -/*
> - * For some kind of reserved memory there might be no struct page available,
> - * so all that can be done to support such 'pages' is to try to convert
> - * pfn to dma address or at the last resort just assume that
> - * dma address == physical address (like it has been assumed in earlier version
> - * of videobuf2-dma-contig
> - */
> -
> -#ifdef __arch_pfn_to_dma
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
> -}
> -#elif defined(__pfn_to_bus)
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__pfn_to_bus(pfn);
> -}
> -#elif defined(__pfn_to_phys)
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__pfn_to_phys(pfn);
> -}
> -#else
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	/* really, we cannot do anything better at this point */
> -	return (dma_addr_t)(pfn) << PAGE_SHIFT;
> -}
> -#endif
> -
>  static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
>  	unsigned long size, enum dma_data_direction dma_dir)
>  {
> @@ -528,7 +500,12 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
>  		for (i = 1; i < n_pages; i++)
>  			if (nums[i-1] + 1 != nums[i])
>  				goto fail_pfnvec;
> -		buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
> +		buf->dma_addr = dma_map_resource(buf->dev,
> +				__pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
> +		if (dma_mapping_error(buf->dev, buf->dma_addr)) {
> +			ret = -ENOMEM;
> +			goto fail_pfnvec;
> +		}
>  		goto out;
>  	}
>  



Thanks,
Mauro
hch@lst.de Jan. 14, 2019, 10:31 a.m. UTC | #2
On Fri, Jan 11, 2019 at 05:54:16PM -0200, Mauro Carvalho Chehab wrote:
> Em Fri, 11 Jan 2019 19:17:31 +0100
> Christoph Hellwig <hch@lst.de> escreveu:
> 
> > vb2_dc_get_userptr pokes into arm direct mapping details to get the
> > resemblance of a dma address for a a physical address that does is
> > not backed by a page struct.  Not only is this not portable to other
> > architectures with dma direct mapping offsets, but also not to uses
> > of IOMMUs of any kind.  Switch to the proper dma_map_resource /
> > dma_unmap_resource interface instead.
> 
> Makes sense to me. I'm assuming that you'll be pushing it together
> with other mm patches, so:

Not really mm, but rather DMA mapping, but yes, I'd love to take it
all together.

Thanks!
Mauro Carvalho Chehab Jan. 14, 2019, 11:04 a.m. UTC | #3
Em Mon, 14 Jan 2019 11:31:39 +0100
Christoph Hellwig <hch@lst.de> escreveu:

> On Fri, Jan 11, 2019 at 05:54:16PM -0200, Mauro Carvalho Chehab wrote:
> > Em Fri, 11 Jan 2019 19:17:31 +0100
> > Christoph Hellwig <hch@lst.de> escreveu:
> >   
> > > vb2_dc_get_userptr pokes into arm direct mapping details to get the
> > > resemblance of a dma address for a a physical address that does is
> > > not backed by a page struct.  Not only is this not portable to other
> > > architectures with dma direct mapping offsets, but also not to uses
> > > of IOMMUs of any kind.  Switch to the proper dma_map_resource /
> > > dma_unmap_resource interface instead.  
> > 
> > Makes sense to me. I'm assuming that you'll be pushing it together
> > with other mm patches, so:  
> 
> Not really mm, but rather DMA mapping, but yes, I'd love to take it
> all together.

Ah, OK! Anyway, feel free to place it altogether. 

It would be good if you could later send us a stable branch where
you merged, in order to allow us to run some tests with the new
DMA mapping patchset and be sure that it won't cause regressions
to videobuf2.

Thank you!

Mauro
hch@lst.de Jan. 14, 2019, 11:12 a.m. UTC | #4
On Mon, Jan 14, 2019 at 09:04:56AM -0200, Mauro Carvalho Chehab wrote:
> It would be good if you could later send us a stable branch where
> you merged, in order to allow us to run some tests with the new
> DMA mapping patchset and be sure that it won't cause regressions
> to videobuf2.

I can do that, but the series as sent should be testable, results
welcome!
Marek Szyprowski Jan. 14, 2019, 12:42 p.m. UTC | #5
Hi Christoph,

On 2019-01-11 19:17, Christoph Hellwig wrote:
> vb2_dc_get_userptr pokes into arm direct mapping details to get the
> resemblance of a dma address for a a physical address that does is
> not backed by a page struct.  Not only is this not portable to other
> architectures with dma direct mapping offsets, but also not to uses
> of IOMMUs of any kind.  Switch to the proper dma_map_resource /
> dma_unmap_resource interface instead.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

There are checks for IOMMU presence in other places in vb2-dma-contig,
so it was used only when no IOMMU is available, but I agree that the
hacky code should be replaced by a generic code if possible.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

V4L2 pipeline works fine on older Exynos-based boards with CMA and IOMMU
disabled.

> ---
>  .../common/videobuf2/videobuf2-dma-contig.c   | 41 ++++---------------
>  1 file changed, 9 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index aff0ab7bf83d..82389aead6ed 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -439,42 +439,14 @@ static void vb2_dc_put_userptr(void *buf_priv)
>  				set_page_dirty_lock(pages[i]);
>  		sg_free_table(sgt);
>  		kfree(sgt);
> +	} else {
> +		dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
> +				   buf->dma_dir, 0);
>  	}
>  	vb2_destroy_framevec(buf->vec);
>  	kfree(buf);
>  }
>  
> -/*
> - * For some kind of reserved memory there might be no struct page available,
> - * so all that can be done to support such 'pages' is to try to convert
> - * pfn to dma address or at the last resort just assume that
> - * dma address == physical address (like it has been assumed in earlier version
> - * of videobuf2-dma-contig
> - */
> -
> -#ifdef __arch_pfn_to_dma
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
> -}
> -#elif defined(__pfn_to_bus)
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__pfn_to_bus(pfn);
> -}
> -#elif defined(__pfn_to_phys)
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	return (dma_addr_t)__pfn_to_phys(pfn);
> -}
> -#else
> -static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
> -{
> -	/* really, we cannot do anything better at this point */
> -	return (dma_addr_t)(pfn) << PAGE_SHIFT;
> -}
> -#endif
> -
>  static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
>  	unsigned long size, enum dma_data_direction dma_dir)
>  {
> @@ -528,7 +500,12 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
>  		for (i = 1; i < n_pages; i++)
>  			if (nums[i-1] + 1 != nums[i])
>  				goto fail_pfnvec;
> -		buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
> +		buf->dma_addr = dma_map_resource(buf->dev,
> +				__pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
> +		if (dma_mapping_error(buf->dev, buf->dma_addr)) {
> +			ret = -ENOMEM;
> +			goto fail_pfnvec;
> +		}
>  		goto out;
>  	}
>  

Best regards

Patch
diff mbox series

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index aff0ab7bf83d..82389aead6ed 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -439,42 +439,14 @@  static void vb2_dc_put_userptr(void *buf_priv)
 				set_page_dirty_lock(pages[i]);
 		sg_free_table(sgt);
 		kfree(sgt);
+	} else {
+		dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
+				   buf->dma_dir, 0);
 	}
 	vb2_destroy_framevec(buf->vec);
 	kfree(buf);
 }
 
-/*
- * For some kind of reserved memory there might be no struct page available,
- * so all that can be done to support such 'pages' is to try to convert
- * pfn to dma address or at the last resort just assume that
- * dma address == physical address (like it has been assumed in earlier version
- * of videobuf2-dma-contig
- */
-
-#ifdef __arch_pfn_to_dma
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
-	return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
-}
-#elif defined(__pfn_to_bus)
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
-	return (dma_addr_t)__pfn_to_bus(pfn);
-}
-#elif defined(__pfn_to_phys)
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
-	return (dma_addr_t)__pfn_to_phys(pfn);
-}
-#else
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
-	/* really, we cannot do anything better at this point */
-	return (dma_addr_t)(pfn) << PAGE_SHIFT;
-}
-#endif
-
 static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
 	unsigned long size, enum dma_data_direction dma_dir)
 {
@@ -528,7 +500,12 @@  static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
 		for (i = 1; i < n_pages; i++)
 			if (nums[i-1] + 1 != nums[i])
 				goto fail_pfnvec;
-		buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
+		buf->dma_addr = dma_map_resource(buf->dev,
+				__pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
+		if (dma_mapping_error(buf->dev, buf->dma_addr)) {
+			ret = -ENOMEM;
+			goto fail_pfnvec;
+		}
 		goto out;
 	}