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Subject[PATCH 1/7 v3] dma-mapping: add generic dma_get_page_shift API
Drivers like NVMe need to be able to determine the page size used for
DMA transfers. Add a new API that defaults to return PAGE_SHIFT on all
architectures.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>

---
v1 -> v2:
Based upon feedback from Christoph Hellwig, implement the IOMMU page
size lookup as a generic DMA API, rather than an architecture-specific
hack.
v2 -> v3:
Based upon feedback from Christoph Hellwig that not all architectures
have moved to dma-mapping-common.h, so move the #ifdef and default to
linux/dma-mapping.h.
---
include/linux/dma-mapping.h | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ac07ff0..7eaba8d 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -95,6 +95,13 @@ static inline u64 dma_get_mask(struct device *dev)
return DMA_BIT_MASK(32);
}

+#ifndef HAVE_ARCH_DMA_GET_PAGE_SHIFT
+static inline unsigned long dma_get_page_shift(struct device *dev)
+{
+ return PAGE_SHIFT;
+}
+#endif
+
#ifdef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
int dma_set_coherent_mask(struct device *dev, u64 mask);
#else
--
1.9.1


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