xen: make xen_create_contiguous_region return the dma address

Modify xen_create_contiguous_region to return the dma address of the
newly contiguous buffer.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>


Changes in v4:
- use virt_to_machine instead of virt_to_bus.

3 files changed, 8 insertions, 5 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index fdc3ba28ca38..6c34d7c03d5b 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2329,7 +2329,8 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
 }
 
 int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
-                                 unsigned int address_bits)
+                                 unsigned int address_bits,
+                                 dma_addr_t *dma_handle)
 {
         unsigned long *in_frames = discontig_frames, out_frame;
         unsigned long  flags;
@@ -2368,6 +2369,7 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
 
         spin_unlock_irqrestore(&xen_reservation_lock, flags);
 
+        *dma_handle = virt_to_machine(vstart).maddr;
         return success ? 0 : -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 1b2277c311d2..b72f31c1e018 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -126,6 +126,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
 {
         int i, rc;
         int dma_bits;
+        dma_addr_t dma_handle;
 
         dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
 
@@ -137,7 +138,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
                         rc = xen_create_contiguous_region(
                                 (unsigned long)buf + (i << IO_TLB_SHIFT),
                                 get_order(slabs << IO_TLB_SHIFT),
-                                dma_bits);
+                                dma_bits, &dma_handle);
                 } while (rc && dma_bits++ < max_dma_bits);
                 if (rc)
                         return rc;
@@ -294,11 +295,10 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                 *dma_handle = dev_addr;
         else {
                 if (xen_create_contiguous_region(vstart, order,
-                                                 fls64(dma_mask)) != 0) {
+                                                 fls64(dma_mask), dma_handle) != 0) {
                         free_pages(vstart, order);
                         return NULL;
                 }
-                *dma_handle = virt_to_machine(ret).maddr;
         }
         memset(ret, 0, size);
         return ret;
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index d6fe062cad6b..9ef704d3a9dd 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -20,7 +20,8 @@ int xen_setup_shutdown_event(void);
 
 extern unsigned long *xen_contiguous_bitmap;
 int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
-                                unsigned int address_bits);
+                                unsigned int address_bits,
+                                dma_addr_t *dma_handle);
 
 void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);