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Subject[RFC PATCH 5/7] swiotlb: Use physical addresses for swiotlb_tbl_unmap_single
Date
This change makes it so that the unmap functionality also uses physical
addresses. This helps to further reduce the use of virt_to_phys and
phys_to_virt functions.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---

drivers/xen/swiotlb-xen.c | 4 ++--
include/linux/swiotlb.h | 3 ++-
lib/swiotlb.c | 35 ++++++++++++++++++-----------------
3 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 8a6035a..4cedc28 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -364,7 +364,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
* Ensure that the address returned is DMA'ble
*/
if (!dma_capable(dev, dev_addr, size)) {
- swiotlb_tbl_unmap_single(dev, phys_to_virt(map), size, dir);
+ swiotlb_tbl_unmap_single(dev, map, size, dir);
dev_addr = 0;
}
return dev_addr;
@@ -388,7 +388,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,

/* NOTE: We use dev_addr here, not paddr! */
if (is_xen_swiotlb_buffer(dev_addr)) {
- swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
return;
}

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 1995f3e..5a5a654 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -43,7 +43,8 @@ extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
phys_addr_t phys, size_t size,
enum dma_data_direction dir);

-extern void swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr,
+extern void swiotlb_tbl_unmap_single(struct device *hwdev,
+ phys_addr_t dma_addr,
size_t size, enum dma_data_direction dir);

extern void swiotlb_tbl_sync_single(struct device *hwdev, char *dma_addr,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 55e052e..41e1d9a 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -510,20 +510,20 @@ phys_addr_t map_single(struct device *hwdev, phys_addr_t phys, size_t size,
/*
* dma_addr is the kernel virtual address of the bounce buffer to unmap.
*/
-void
-swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr, size_t size,
- enum dma_data_direction dir)
+void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t dma_addr,
+ size_t size, enum dma_data_direction dir)
{
unsigned long flags;
int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- int index = (dma_addr - (char *)phys_to_virt(io_tlb_start)) >> IO_TLB_SHIFT;
+ int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t phys = io_tlb_orig_addr[index];

/*
* First, sync the memory before unmapping the entry
*/
if (phys && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
- swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
+ swiotlb_bounce(phys, phys_to_virt(dma_addr),
+ size, DMA_FROM_DEVICE);

/*
* Return the buffer to the free list by setting the corresponding
@@ -616,17 +616,18 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,

ret = phys_to_virt(paddr);
dev_addr = phys_to_dma(hwdev, paddr);
- }

- /* Confirm address can be DMA'd by device */
- if (dev_addr + size - 1 > dma_mask) {
- printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
- (unsigned long long)dma_mask,
- (unsigned long long)dev_addr);
+ /* Confirm address can be DMA'd by device */
+ if (dev_addr + size - 1 > dma_mask) {
+ printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
+ (unsigned long long)dma_mask,
+ (unsigned long long)dev_addr);

- /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
- swiotlb_tbl_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
- return NULL;
+ /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
+ swiotlb_tbl_unmap_single(hwdev, paddr,
+ size, DMA_TO_DEVICE);
+ return NULL;
+ }
}

*dma_handle = dev_addr;
@@ -647,7 +648,7 @@ swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
free_pages((unsigned long)vaddr, get_order(size));
else
/* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
- swiotlb_tbl_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
}
EXPORT_SYMBOL(swiotlb_free_coherent);

@@ -711,7 +712,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,

/* Ensure that the address returned is DMA'ble */
if (!dma_capable(dev, dev_addr, size)) {
- swiotlb_tbl_unmap_single(dev, phys_to_virt(map), size, dir);
+ swiotlb_tbl_unmap_single(dev, map, size, dir);
return phys_to_dma(dev, io_tlb_overflow_buffer);
}

@@ -735,7 +736,7 @@ static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
BUG_ON(dir == DMA_NONE);

if (is_swiotlb_buffer(paddr)) {
- swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
return;
}



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