* [PATCH v2] swiotlb: manipulate orig_addr when tlb_addr has offset
[not found] <CGME20210510091047epcas2p46daccaa59f30e7444be0ff2b5955228c@epcas2p4.samsung.com>
@ 2021-05-10 9:10 ` Chanho Park
2021-05-10 9:18 ` Christoph Hellwig
0 siblings, 1 reply; 2+ messages in thread
From: Chanho Park @ 2021-05-10 9:10 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk, Christoph Hellwig
Cc: Marek Szyprowski, Robin Murphy, iommu, linux-kernel, Bumyong Lee,
Chanho Park
From: Bumyong Lee <bumyong.lee@samsung.com>
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 due to below case.
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 <bumyong.lee@samsung.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
---
Changes since v1:
- Move swiotlb_align_offset to avoid forward declaration
- Make tlb_offset calculation as single assignment
kernel/dma/swiotlb.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8ca7d505d61c..e50df8d8f87e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -334,6 +334,14 @@ void __init swiotlb_exit(void)
io_tlb_default_mem = NULL;
}
+/*
+ * Return the offset into a iotlb slot required to keep the device happy.
+ */
+static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
+{
+ return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
+}
+
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
@@ -346,10 +354,17 @@ 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 = (tlb_addr & (IO_TLB_SIZE - 1)) -
+ 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",
@@ -390,14 +405,6 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
#define slot_addr(start, idx) ((start) + ((idx) << IO_TLB_SHIFT))
-/*
- * Return the offset into a iotlb slot required to keep the device happy.
- */
-static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
-{
- return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
-}
-
/*
* Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
*/
--
2.31.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] swiotlb: manipulate orig_addr when tlb_addr has offset
2021-05-10 9:10 ` [PATCH v2] swiotlb: manipulate orig_addr when tlb_addr has offset Chanho Park
@ 2021-05-10 9:18 ` Christoph Hellwig
0 siblings, 0 replies; 2+ messages in thread
From: Christoph Hellwig @ 2021-05-10 9:18 UTC (permalink / raw)
To: Chanho Park
Cc: Konrad Rzeszutek Wilk, Christoph Hellwig, Marek Szyprowski,
Robin Murphy, iommu, linux-kernel, Bumyong Lee
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-05-10 9:10 ` [PATCH v2] swiotlb: manipulate orig_addr when tlb_addr has offset Chanho Park
2021-05-10 9:18 ` Christoph Hellwig
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