Bug Fix arch/ia64/kernel/pci-dma.c: fix recursive dma_supported() call in iommu_dma_supporte

In commit dfb805e831cc5306b14eacd64e0b36d0d973ee0d, dma_ops->dma_supported = iommu_dma_supported;

This dma_ops->dma_supported is first called in platform_dma_init() during kernel boot. Then dma_ops->dma_supported will be called recursively in iommu_dma_supported.

Kernel can not boot because kernel can not get out of iommu_dma_supported until it runs out of stack memory.

Signed-off-by Fenghua Yu <[email protected]>

---

 arch/ia64/kernel/pci-dma.c |    5 -----
 1 files changed, 5 deletions(-)

arch/ia64/kernel/pci-dma.c +0 -6

index 0569596..f6b1ff0 100644
@@ -69,11 +69,6 @@ iommu_dma_init(void)
 
 int iommu_dma_supported(struct device *dev, u64 mask)
 {
-	struct dma_map_ops *ops = platform_dma_get_ops(dev);
-
-	if (ops->dma_supported)
-		return ops->dma_supported(dev, mask);
-
 	/* Copied from i386. Doesn't make much sense, because it will
 	   only work for pci_alloc_coherent.
 	   The caller just has to use GFP_DMA in this case. */
--

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On Tue, 4 Aug 2009 15:35:26 -0700
Fenghua Yu <[email protected]> wrote:

Quoted 2 lines

In commit dfb805e831cc5306b14eacd64e0b36d0d973ee0d, dma_ops->dma_supported = iommu_dma_supported;

Hmm, the dfb805e831cc5306b14eacd64e0b36d0d973ee0d commit touches only dma_ops->mapping_error. It doesn't like like that this commit is related with the bug.

I guess that I added the bug when I rewrote IA64 dma operations.