Fail dma_alloc_coherent on dma less devices 

This should fix an oops with PCMCIA PATA devices

http://bugzilla.kernel.org/show_bug.cgi?id=8424


Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/x86_64/kernel/pci-dma.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux/arch/x86_64/kernel/pci-dma.c
===================================================================
--- linux.orig/arch/x86_64/kernel/pci-dma.c
+++ linux/arch/x86_64/kernel/pci-dma.c
@@ -82,6 +82,10 @@ dma_alloc_coherent(struct device *dev, s
 	if (dma_mask == 0)
 		dma_mask = DMA_32BIT_MASK;
 
+	/* Device not DMA able */
+	if (dev->dma_mask == NULL)
+		return NULL;
+
 	/* Don't invoke OOM killer */
 	gfp |= __GFP_NORETRY;