From: Fugang Duan <[email protected]>
dma_map_sg() may use swiotlb buffer when kernel parameter include
"swiotlb=force" or the dma_addr is out of dev->dma_mask range. After
DMA complete the memory moving from device to memory, then user call
dma_sync_sg_for_cpu() to sync with DMA buffer, and copy the original
virtual buffer to other space.
So dma_direct_sync_sg_for_cpu() should use swiotlb physical addr, not
the original physical addr from sg_phys(sg).
dma_direct_sync_sg_for_device() also has the similar issue, correct it.
Fixes: 55897af63091("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
Signed-off-by: Fugang Duan <[email protected]>
---
kernel/dma/direct.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index b90e1ae..0e87f86 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -242,12 +242,14 @@ void dma_direct_sync_sg_for_device(struct device *dev,
int i;
for_each_sg(sgl, sg, nents, i) {
- if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
- swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
+ phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
+ if (unlikely(is_swiotlb_buffer(paddr)))
+ swiotlb_tbl_sync_single(dev, paddr, sg->length,
dir, SYNC_FOR_DEVICE);
if (!dev_is_dma_coherent(dev))
- arch_sync_dma_for_device(dev, sg_phys(sg), sg->length,
+ arch_sync_dma_for_device(dev, paddr, sg->length,
dir);
}
}
@@ -279,11 +281,13 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
int i;
for_each_sg(sgl, sg, nents, i) {
+ phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
if (!dev_is_dma_coherent(dev))
- arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
-
- if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
- swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length, dir,
+ arch_sync_dma_for_cpu(dev, paddr, sg->length, dir);
+
+ if (unlikely(is_swiotlb_buffer(paddr)))
+ swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
SYNC_FOR_CPU);
}
--
2.7.4
On 19/07/2019 10:26, [email protected] wrote:
> From: Fugang Duan <[email protected]>
>
> dma_map_sg() may use swiotlb buffer when kernel parameter include
> "swiotlb=force" or the dma_addr is out of dev->dma_mask range. After
> DMA complete the memory moving from device to memory, then user call
> dma_sync_sg_for_cpu() to sync with DMA buffer, and copy the original
> virtual buffer to other space.
>
> So dma_direct_sync_sg_for_cpu() should use swiotlb physical addr, not
> the original physical addr from sg_phys(sg).
>
> dma_direct_sync_sg_for_device() also has the similar issue, correct it.
Yikes, that was unfortunate. There aren't too many users of
dma_sync_sg*(), but I note that a few of them are in and around v4l2, so
this could well explain the video brokenness that Al reported.
AFAICS the fix looks appropriate;
Reviewed-by: Robin Murphy <[email protected]>
> Fixes: 55897af63091("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
> Signed-off-by: Fugang Duan <[email protected]>
> ---
> kernel/dma/direct.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index b90e1ae..0e87f86 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -242,12 +242,14 @@ void dma_direct_sync_sg_for_device(struct device *dev,
> int i;
>
> for_each_sg(sgl, sg, nents, i) {
> - if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
> - swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
> + phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
> +
> + if (unlikely(is_swiotlb_buffer(paddr)))
> + swiotlb_tbl_sync_single(dev, paddr, sg->length,
> dir, SYNC_FOR_DEVICE);
>
> if (!dev_is_dma_coherent(dev))
> - arch_sync_dma_for_device(dev, sg_phys(sg), sg->length,
> + arch_sync_dma_for_device(dev, paddr, sg->length,
> dir);
> }
> }
> @@ -279,11 +281,13 @@ void dma_direct_sync_sg_for_cpu(struct device *dev,
> int i;
>
> for_each_sg(sgl, sg, nents, i) {
> + phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
> +
> if (!dev_is_dma_coherent(dev))
> - arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
> -
> - if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
> - swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length, dir,
> + arch_sync_dma_for_cpu(dev, paddr, sg->length, dir);
> +
> + if (unlikely(is_swiotlb_buffer(paddr)))
> + swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
> SYNC_FOR_CPU);
> }
>
>
Thanks,
applied to the dma-mapping tree and I'll sent it to Linus this
weekend.