Re: Swiotlb breaks pseries
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2009-06-23 09:32:38
On Tue, 2009-06-23 at 19:13 +1000, Michael Ellerman wrote:
Hi all, Turning on SWIOTLB selects or enables PPC_NEED_DMA_SYNC_OPS, which means we get the non empty versions of dma_sync_* in asm/dma-mapping.h On my pseries machine the dma_ops have no such routines and we die with a null pointer - this patch gets it booting, is there a more elegant way to do it?
No that's the best way (checking for NULL in the inlines), avoids calling through a function pointer when not needed, since this can be a fairly hot path, especially with networking. Cheers, Ben.
quoted hunk ↗ jump to hunk
cheersdiff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h index 3d9e887..b44aaab 100644 --- a/arch/powerpc/include/asm/dma-mapping.h +++ b/arch/powerpc/include/asm/dma-mapping.h@@ -309,7 +309,9 @@ static inline void dma_sync_single_for_cpu(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_single_range_for_cpu(dev, dma_handle, 0, + + if (dma_ops->sync_single_range_for_cpu) + dma_ops->sync_single_range_for_cpu(dev, dma_handle, 0, size, direction); }@@ -320,7 +322,9 @@ static inline void dma_sync_single_for_device(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_single_range_for_device(dev, dma_handle, + + if (dma_ops->sync_single_range_for_device) + dma_ops->sync_single_range_for_device(dev, dma_handle, 0, size, direction); }@@ -331,7 +335,9 @@ static inline void dma_sync_sg_for_cpu(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_sg_for_cpu(dev, sgl, nents, direction); + + if (dma_ops->sync_sg_for_cpu) + dma_ops->sync_sg_for_cpu(dev, sgl, nents, direction); } static inline void dma_sync_sg_for_device(struct device *dev,@@ -341,7 +347,9 @@ static inline void dma_sync_sg_for_device(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_sg_for_device(dev, sgl, nents, direction); + + if (dma_ops->sync_sg_for_device) + dma_ops->sync_sg_for_device(dev, sgl, nents, direction); } static inline void dma_sync_single_range_for_cpu(struct device *dev,@@ -351,7 +359,9 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_single_range_for_cpu(dev, dma_handle, + + if (dma_ops->sync_single_range_for_cpu) + dma_ops->sync_single_range_for_cpu(dev, dma_handle, offset, size, direction); }@@ -362,7 +372,9 @@ static inline void dma_sync_single_range_for_device(struct device *dev, struct dma_mapping_ops *dma_ops = get_dma_ops(dev); BUG_ON(!dma_ops); - dma_ops->sync_single_range_for_device(dev, dma_handle, offset, + + if (dma_ops->sync_single_range_for_device) + dma_ops->sync_single_range_for_device(dev, dma_handle, offset, size, direction); } #else /* CONFIG_PPC_NEED_DMA_SYNC_OPS */