x86: don't do dma if mask is NULL.

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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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 f134de3833a2..d2f70744a93a 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: