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Subject[PATCH 1/5] swiotlb: Introduce swiotlb_max_mapping_size()
Date
From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be remapped
by the SWIOTLB implementation. This function will be later
exposed to users through the DMA-API.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
include/linux/swiotlb.h | 5 +++++
kernel/dma/swiotlb.c | 5 +++++
2 files changed, 10 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 7c007ed7505f..1c22d96e1742 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -62,6 +62,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,

extern int
swiotlb_dma_supported(struct device *hwdev, u64 mask);
+size_t swiotlb_max_mapping_size(struct device *dev);

#ifdef CONFIG_SWIOTLB
extern enum swiotlb_force swiotlb_force;
@@ -95,6 +96,10 @@ static inline unsigned int swiotlb_max_segment(void)
{
return 0;
}
+static inline size_t swiotlb_max_mapping_size(struct device *dev)
+{
+ return SIZE_MAX;
+}
#endif /* CONFIG_SWIOTLB */

extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1fb6fd68b9c7..9cb21259cb0b 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -662,3 +662,8 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask)
{
return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
}
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+ return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+}
--
2.17.1
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