From: Bumyong Lee <[email protected]>
in case of driver wants to sync part of ranges with offset,
swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with offset
it makes data mismatch
it removed from "swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single",
but it have to be recovered
1. Get dma_addr_t from dma_map_single()
dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE);
|<---------------vsize------------->|
+-----------------------------------+
| | original buffer
+-----------------------------------+
vaddr
swiotlb_align_offset
|<----->|<---------------vsize------------->|
+-------+-----------------------------------+
| | | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
2. Do something
3. Sync dma_addr_t through dma_sync_single_for_device(..)
dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE);
Error case.
copy data to original buffer.
but it is from base addr in original buffer
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- size ->|
+-----------------------------------+
|##########| | original buffer
+-----------------------------------+
vaddr
FIX. copy data to original buffer.
but it is from base addr in original buffer
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- offset ->|<- size ->|
+-----------------------------------+
| |##########| | original buffer
+-----------------------------------+
vaddr
Fixes: 16fc3cef33a0 ("swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single")
Signed-off-by: Bumyong Lee <[email protected]>
Signed-off-by: Chanho Park <[email protected]>
---
kernel/dma/swiotlb.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8ca7d505d61c..e8243725e298 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -334,6 +334,7 @@ void __init swiotlb_exit(void)
io_tlb_default_mem = NULL;
}
+static unsigned int swiotlb_align_offset(struct device *dev, u64 addr);
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
@@ -346,10 +347,17 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
size_t alloc_size = mem->slots[index].alloc_size;
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = phys_to_virt(tlb_addr);
+ unsigned int tlb_offset;
if (orig_addr == INVALID_PHYS_ADDR)
return;
+ tlb_offset = (unsigned int)tlb_addr & (IO_TLB_SIZE - 1);
+ tlb_offset -= swiotlb_align_offset(dev, orig_addr);
+
+ orig_addr += tlb_offset;
+ alloc_size -= tlb_offset;
+
if (size > alloc_size) {
dev_WARN_ONCE(dev, 1,
"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
--
2.31.1
On Mon, May 10, 2021 at 05:30:57PM +0900, Chanho Park wrote:
> +static unsigned int swiotlb_align_offset(struct device *dev, u64 addr);
Please just move swiotlb_align_offset up to avoid the forward declaration.
> /*
> * Bounce: copy the swiotlb buffer from or back to the original dma location
> */
> @@ -346,10 +347,17 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
> size_t alloc_size = mem->slots[index].alloc_size;
> unsigned long pfn = PFN_DOWN(orig_addr);
> unsigned char *vaddr = phys_to_virt(tlb_addr);
> + unsigned int tlb_offset;
>
> if (orig_addr == INVALID_PHYS_ADDR)
> return;
>
> + tlb_offset = (unsigned int)tlb_addr & (IO_TLB_SIZE - 1);
> + tlb_offset -= swiotlb_align_offset(dev, orig_addr);
Nit: I'd write this as:
tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) -
swiotlb_align_offset(dev, orig_addr);
as there is no need for the cast, and just having a single assignment
is easier to follow.
(RESEND due to wrong encrypted message setting)
Hi,
> On Mon, May 10, 2021 at 05:30:57PM +0900, Chanho Park wrote:
> > +static unsigned int swiotlb_align_offset(struct device *dev, u64
> > +addr);
>
> Please just move swiotlb_align_offset up to avoid the forward declaration.
Okay. I'll move the position of the function next patch.
>
> > /*
> > * Bounce: copy the swiotlb buffer from or back to the original dma
> location
> > */
> > @@ -346,10 +347,17 @@ static void swiotlb_bounce(struct device *dev,
> phys_addr_t tlb_addr, size_t size
> > size_t alloc_size = mem->slots[index].alloc_size;
> > unsigned long pfn = PFN_DOWN(orig_addr);
> > unsigned char *vaddr = phys_to_virt(tlb_addr);
> > + unsigned int tlb_offset;
> >
> > if (orig_addr == INVALID_PHYS_ADDR)
> > return;
> >
> > + tlb_offset = (unsigned int)tlb_addr & (IO_TLB_SIZE - 1);
> > + tlb_offset -= swiotlb_align_offset(dev, orig_addr);
>
> Nit: I'd write this as:
>
> tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) -
> swiotlb_align_offset(dev, orig_addr);
>
> as there is no need for the cast, and just having a single assignment is
> easier to follow.
Great. It can be a single assignment as you suggested.
Best Regards,
Chanho Park