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swiotlb: move orig addr and size validation into swiotlb_bounce

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Move the code to find and validate the original buffer address and size
from the callers into swiotlb_bounce.  This means a tiny bit of extra
work in the swiotlb_map path, but avoids code duplication and a leads to
a better code structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Christoph Hellwig 2021-03-01 08:44:25 +01:00 committed by Konrad Rzeszutek Wilk
parent 2973073a80
commit 2bdba622c3
1 changed files with 23 additions and 36 deletions
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59
kernel/dma/swiotlb.c
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@ -460,12 +460,25 @@ void __init swiotlb_exit(void)
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
enum dma_data_direction dir)
{
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
size_t alloc_size = io_tlb_alloc_size[index];
phys_addr_t orig_addr = io_tlb_orig_addr[index];
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = phys_to_virt(tlb_addr);
if (orig_addr == INVALID_PHYS_ADDR)
return;
if (size > alloc_size) {
dev_WARN_ONCE(dev, 1,
"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
alloc_size, size);
size = alloc_size;
}
if (PageHighMem(pfn_to_page(pfn))) {
/* The buffer does not have a mapping. Map it in and copy */
unsigned int offset = orig_addr & ~PAGE_MASK;
@ -644,21 +657,10 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
tlb_addr = slot_addr(io_tlb_start, index) + offset;
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE);
return tlb_addr;
}
static void validate_sync_size_and_truncate(struct device *hwdev, size_t alloc_size, size_t *size)
{
if (*size > alloc_size) {
/* Warn and truncate mapping_size */
dev_WARN_ONCE(hwdev, 1,
"Attempt for buffer overflow. Original size: %zu. Mapping size: %zu.\n",
alloc_size, *size);
*size = alloc_size;
}
}
/*
* tlb_addr is the physical address of the bounce buffer to unmap.
*/
@ -669,19 +671,15 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
unsigned long flags;
unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr);
int index = (tlb_addr - offset - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];
size_t alloc_size = io_tlb_alloc_size[index];
int i, count, nslots = nr_slots(alloc_size + offset);
validate_sync_size_and_truncate(hwdev, alloc_size, &mapping_size);
int nslots = nr_slots(io_tlb_alloc_size[index] + offset);
int count, i;
/*
* 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, mapping_size, DMA_FROM_DEVICE);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
swiotlb_bounce(hwdev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
/*
* Return the buffer to the free list by setting the corresponding
@ -721,27 +719,16 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir,
enum dma_sync_target target)
{
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
size_t alloc_size = io_tlb_alloc_size[index];
phys_addr_t orig_addr = io_tlb_orig_addr[index];
if (orig_addr == INVALID_PHYS_ADDR)
return;
validate_sync_size_and_truncate(hwdev, alloc_size, &size);
switch (target) {
case SYNC_FOR_CPU:
if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
swiotlb_bounce(orig_addr, tlb_addr,
size, DMA_FROM_DEVICE);
swiotlb_bounce(hwdev, tlb_addr, size, DMA_FROM_DEVICE);
else
BUG_ON(dir != DMA_TO_DEVICE);
break;
case SYNC_FOR_DEVICE:
if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
swiotlb_bounce(orig_addr, tlb_addr,
size, DMA_TO_DEVICE);
swiotlb_bounce(hwdev, tlb_addr, size, DMA_TO_DEVICE);
else
BUG_ON(dir != DMA_FROM_DEVICE);
break;