From 7453c549f5f6485c0d79cad7844870dcc7d1b34d Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 20 Dec 2016 10:02:02 -0500 Subject: swiotlb: Export swiotlb_max_segment to users So they can figure out what is the optimal number of pages that can be contingously stitched together without fear of bounce buffer. We also expose an mechanism for sub-users of SWIOTLB API, such as Xen-SWIOTLB to set the max segment value. And lastly if swiotlb=force is set (which mandates we bounce buffer everything) we set max_segment so at least we can bounce buffer one 4K page instead of a giant 512KB one for which we may not have space. Signed-off-by: Konrad Rzeszutek Wilk Reported-and-Tested-by: Juergen Gross --- include/linux/swiotlb.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index d9c84a9cde3d..4ee479f2f355 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -114,11 +114,14 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask); #ifdef CONFIG_SWIOTLB extern void __init swiotlb_free(void); +unsigned int swiotlb_max_segment(void); #else static inline void swiotlb_free(void) { } +static inline unsigned int swiotlb_max_segment(void) { return 0; } #endif extern void swiotlb_print_info(void); extern int is_swiotlb_buffer(phys_addr_t paddr); +extern void swiotlb_set_max_segment(unsigned int); #endif /* __LINUX_SWIOTLB_H */ -- cgit v1.2.3