Commit 2bdba622 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Konrad Rzeszutek Wilk
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swiotlb: move orig addr and size validation into swiotlb_bounce 



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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 2973073a

kernel/dma/swiotlb.c

+23 −36
Original line number Diff line number Diff line
@@ -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;