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Subject: [mm PATCH v2 01/26] swiotlb: Drop unused functions swiotlb_map_sg and swiotlb_unmap_sg

There are no users for swiotlb_map_sg or swiotlb_unmap_sg so we might as
well just drop them.

Cc: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Alexander Duyck <[email protected]>
---

v2: Added swiotlb_unmap_sg to functions dropped.

include/linux/swiotlb.h | 8 --------
lib/swiotlb.c | 16 ----------------
2 files changed, 24 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 5f81f8a..f0d2589 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -73,14 +73,6 @@ extern void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
unsigned long attrs);

extern int
-swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
- enum dma_data_direction dir);
-
-extern void
-swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents,
- enum dma_data_direction dir);
-
-extern int
swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
enum dma_data_direction dir,
unsigned long attrs);
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 22e13a0..5005316 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -910,14 +910,6 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
}
EXPORT_SYMBOL(swiotlb_map_sg_attrs);

-int
-swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
- enum dma_data_direction dir)
-{
- return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, 0);
-}
-EXPORT_SYMBOL(swiotlb_map_sg);
-
/*
* Unmap a set of streaming mode DMA translations. Again, cpu read rules
* concerning calls here are the same as for swiotlb_unmap_page() above.
@@ -938,14 +930,6 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
}
EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);

-void
-swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
- enum dma_data_direction dir)
-{
- return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, 0);
-}
-EXPORT_SYMBOL(swiotlb_unmap_sg);
-
/*
* Make physical memory consistent for a set of streaming mode DMA translations
* after a transfer.

2016-11-02 17:14:30

by Duyck, Alexander H

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Subject: [mm PATCH v2 06/26] arch/avr32: Add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the DMA
APIs in the arch/arm folder. This change is meant to correct that so that
we get consistent behavior.

Acked-by: Hans-Christian Noren Egtvedt <[email protected]>
Signed-off-by: Alexander Duyck <[email protected]>
---
arch/avr32/mm/dma-coherent.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/avr32/mm/dma-coherent.c b/arch/avr32/mm/dma-coherent.c
index 58610d0..54534e5 100644
--- a/arch/avr32/mm/dma-coherent.c
+++ b/arch/avr32/mm/dma-coherent.c
@@ -146,7 +146,8 @@ static dma_addr_t avr32_dma_map_page(struct device *dev, struct page *page,
{
void *cpu_addr = page_address(page) + offset;

- dma_cache_sync(dev, cpu_addr, size, direction);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ dma_cache_sync(dev, cpu_addr, size, direction);
return virt_to_bus(cpu_addr);
}

@@ -162,6 +163,10 @@ static int avr32_dma_map_sg(struct device *dev, struct scatterlist *sglist,

sg->dma_address = page_to_bus(sg_page(sg)) + sg->offset;
virt = sg_virt(sg);
+
+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ continue;
+
dma_cache_sync(dev, virt, sg->length, direction);
}

2016-11-02 17:14:42

by Duyck, Alexander H

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2016-11-02 17:15:13

by Duyck, Alexander H

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.. snip..
> @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
> * First, sync the memory before unmapping the entry
> */
> if (orig_addr != INVALID_PHYS_ADDR &&
> + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
> swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
>
> @@ -654,7 +659,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
> * GFP_DMA memory; fall back on map_single(), which
> * will grab memory from the lowest available address range.
> */
> - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
> + phys_addr_t paddr = map_single(hwdev, 0, size,
> + DMA_FROM_DEVICE, 0);
> if (paddr == SWIOTLB_MAP_ERROR)
> goto err_warn;
>
> @@ -669,7 +675,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>
> /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
> swiotlb_tbl_unmap_single(hwdev, paddr,
> - size, DMA_TO_DEVICE);
> + size, DMA_TO_DEVICE,
> + DMA_ATTR_SKIP_CPU_SYNC);

This I believe is redundant. That is swiotlb_tbl_unmap_single only
does an bounce if the dir is DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.

I added /* optional. */
> goto err_warn;
> }
> }
> @@ -699,7 +706,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
> free_pages((unsigned long)vaddr, get_order(size));
> else
> /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
> - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
> + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, 0);

.. but here you choose to put 0? I changed that to
DMA_ATTR_SKIP_CPU_SYNC and expanded the comment above.

Time to test the patches.

2016-11-05 23:13:35

by Alexander Duyck

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Subject: Re: [mm PATCH v2 03/26] swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC

On Sat, Nov 5, 2016 at 12:39 PM, Konrad Rzeszutek Wilk
<[email protected]> wrote:
> .. snip..
>> @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
>> * First, sync the memory before unmapping the entry
>> */
>> if (orig_addr != INVALID_PHYS_ADDR &&
>> + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
>> ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
>> swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
>>
>> @@ -654,7 +659,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>> * GFP_DMA memory; fall back on map_single(), which
>> * will grab memory from the lowest available address range.
>> */
>> - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
>> + phys_addr_t paddr = map_single(hwdev, 0, size,
>> + DMA_FROM_DEVICE, 0);
>> if (paddr == SWIOTLB_MAP_ERROR)
>> goto err_warn;
>>
>> @@ -669,7 +675,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>>
>> /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
>> swiotlb_tbl_unmap_single(hwdev, paddr,
>> - size, DMA_TO_DEVICE);
>> + size, DMA_TO_DEVICE,
>> + DMA_ATTR_SKIP_CPU_SYNC);
>
> This I believe is redundant. That is swiotlb_tbl_unmap_single only
> does an bounce if the dir is DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.
>
> I added /* optional. */

You are probably right. I don't need to add the DMA_ATTR_SKIP_CPU_SYNC here.

>> goto err_warn;
>> }
>> }
>> @@ -699,7 +706,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>> free_pages((unsigned long)vaddr, get_order(size));
>> else
>> /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
>> - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
>> + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, 0);
>
> .. but here you choose to put 0? I changed that to
> DMA_ATTR_SKIP_CPU_SYNC and expanded the comment above.
>
> Time to test the patches.

I think I had probably realized the fact that I didn't need it above
and so just used 0 here. I can clean this up and resubmit if you
want.

Do you want me to just split this patch set up so that I submit the
swiotlb patches to you and leave the rest of the patches for the mm
tree?

Thanks.

- Alex