[PATCH 26/28] x86: return conditional to mmu

[Glauber Costa <gcosta@redhat.com>]

Just return our allocation if we don't have an mmu. For i386, where this patch
is being applied, we never have. So our goal is just to have the code to look like
x86_64's.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
---
 arch/x86/kernel/pci-dma_32.c |   34 ++++++++++++++++++++++++++++++++--
 1 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 5450bd1..f134de3 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -116,12 +116,42 @@ again:
 				gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
 				goto again;
 			}
+
+			/* Let low level make its own zone decisions */
+			gfp &= ~(GFP_DMA32|GFP_DMA);
+
+			if (dma_ops->alloc_coherent)
+				return dma_ops->alloc_coherent(dev, size,
+							   dma_handle, gfp);
+			return NULL;
+
 		}
 		memset(ret, 0, size);
-		*dma_handle = bus;
+		if (!mmu) {
+			*dma_handle = bus;
+			return ret;
+		}
+	}
+
+	if (dma_ops->alloc_coherent) {
+		free_pages((unsigned long)ret, get_order(size));
+		gfp &= ~(GFP_DMA|GFP_DMA32);
+		return dma_ops->alloc_coherent(dev, size, dma_handle, gfp);
+	}
+
+	if (dma_ops->map_simple) {
+		*dma_handle = dma_ops->map_simple(dev, virt_to_phys(ret),
+					      size,
+					      PCI_DMA_BIDIRECTIONAL);
+		if (*dma_handle != bad_dma_address)
+			return ret;
 	}
 
-	return ret;
+	if (panic_on_overflow)
+		panic("dma_alloc_coherent: IOMMU overflow by %lu bytes\n",
+		      (unsigned long)size);
+	free_pages((unsigned long)ret, get_order(size));
+	return NULL;
 }
 EXPORT_SYMBOL(dma_alloc_coherent);
 
-- 
1.5.0.6