[PATCH 27/28] x86: don't do dma if mask is NULL.

[Glauber Costa <gcosta@redhat.com>]

if the device hasn't provided a mask, abort allocation.
Note that we're using a fallback device now, so it does not cover
the case of a NULL device: just drivers passing NULL masks around.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
---
 arch/x86/kernel/pci-dma_32.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index f134de3..d2f7074 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -91,6 +91,9 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
 	if (dma_mask == 0)
 		dma_mask = DMA_32BIT_MASK;
 
+	if (dev->dma_mask == NULL)
+		return NULL;
+
 	/* Don't invoke OOM killer */
 	gfp |= __GFP_NORETRY;
 again:
-- 
1.5.0.6