1 files changed, 31 insertions, 0 deletions

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 0a1408abcc62..4e612d20170a 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -134,6 +134,37 @@ unsigned long iommu_num_pages(unsigned long addr, unsigned long len)
 EXPORT_SYMBOL(iommu_num_pages);
 #endif
 
+void *dma_generic_alloc_coherent(struct device *dev, size_t size,
+                                 dma_addr_t *dma_addr, gfp_t flag)
+{
+        unsigned long dma_mask;
+        struct page *page;
+        dma_addr_t addr;
+
+        dma_mask = dma_alloc_coherent_mask(dev, flag);
+
+        flag |= __GFP_ZERO;
+again:
+        page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
+        if (!page)
+                return NULL;
+
+        addr = page_to_phys(page);
+        if (!is_buffer_dma_capable(dma_mask, addr, size)) {
+                __free_pages(page, get_order(size));
+
+                if (dma_mask < DMA_32BIT_MASK && !(flag & GFP_DMA)) {
+                        flag = (flag & ~GFP_DMA32) | GFP_DMA;
+                        goto again;
+                }
+
+                return NULL;
+        }
+
+        *dma_addr = addr;
+        return page_address(page);
+}
+
 /*
  * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
  * documentation.