swiotlb: Return physical addresses when calling swiotlb_tbl_map_single
This change makes it so that swiotlb_tbl_map_single will return a physical
address instead of a virtual address when called. The advantage to this once
again is that we are avoiding a number of virt_to_phys and phys_to_virt
translations by working with everything as a physical address.
One change I had to make in order to support using physical addresses is that
I could no longer trust 0 to be a invalid physical address on all platforms.
So instead I made it so that ~0 is returned on error. This should never be a
valid return value as it implies that only one byte would be available for
use.
In order to clarify things since we now have 2 physical addresses in use
inside of swiotlb_tbl_map_single I am renaming phys to orig_addr, and
dma_addr to tlb_addr. This way is should be clear that orig_addr is
contained within io_orig_addr and tlb_addr is an address within the
io_tlb_addr buffer.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 58db6df..8a6035a 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -338,9 +338,8 @@
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- phys_addr_t phys = page_to_phys(page) + offset;
+ phys_addr_t map, phys = page_to_phys(page) + offset;
dma_addr_t dev_addr = xen_phys_to_bus(phys);
- void *map;
BUG_ON(dir == DMA_NONE);
/*
@@ -356,16 +355,16 @@
* Oh well, have to allocate and map a bounce buffer.
*/
map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
- if (!map)
+ if (map == SWIOTLB_MAP_ERROR)
return DMA_ERROR_CODE;
- dev_addr = xen_virt_to_bus(map);
+ dev_addr = xen_phys_to_bus(map);
/*
* Ensure that the address returned is DMA'ble
*/
if (!dma_capable(dev, dev_addr, size)) {
- swiotlb_tbl_unmap_single(dev, map, size, dir);
+ swiotlb_tbl_unmap_single(dev, phys_to_virt(map), size, dir);
dev_addr = 0;
}
return dev_addr;
@@ -494,11 +493,12 @@
if (swiotlb_force ||
!dma_capable(hwdev, dev_addr, sg->length) ||
range_straddles_page_boundary(paddr, sg->length)) {
- void *map = swiotlb_tbl_map_single(hwdev,
- start_dma_addr,
- sg_phys(sg),
- sg->length, dir);
- if (!map) {
+ phys_addr_t map = swiotlb_tbl_map_single(hwdev,
+ start_dma_addr,
+ sg_phys(sg),
+ sg->length,
+ dir);
+ if (map == SWIOTLB_MAP_ERROR) {
/* Don't panic here, we expect map_sg users
to do proper error handling. */
xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
@@ -506,7 +506,7 @@
sgl[0].dma_length = 0;
return DMA_ERROR_CODE;
}
- sg->dma_address = xen_virt_to_bus(map);
+ sg->dma_address = xen_phys_to_bus(map);
} else
sg->dma_address = dev_addr;
sg->dma_length = sg->length;