5.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Joerg Roedel <[email protected]> commit 492366f7b4237257ef50ca9c431a6a0d50225aca upstream. This function will be used from dma_direct code to determine the maximum segment size of a dma mapping. Cc: [email protected] Reviewed-by: Konrad Rzeszutek Wilk <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/linux/swiotlb.h | 6 ++++++ kernel/dma/swiotlb.c | 9 +++++++++ 2 files changed, 15 insertions(+) --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -77,6 +77,7 @@ bool swiotlb_map(struct device *dev, phy void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev); +bool is_swiotlb_active(void); #else #define swiotlb_force SWIOTLB_NO_FORCE static inline bool is_swiotlb_buffer(phys_addr_t paddr) @@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping { return SIZE_MAX; } + +static inline bool is_swiotlb_active(void) +{ + return false; +} #endif /* CONFIG_SWIOTLB */ extern void swiotlb_print_info(void); --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct d { return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE; } + +bool is_swiotlb_active(void) +{ + /* + * When SWIOTLB is initialized, even if io_tlb_start points to physical + * address zero, io_tlb_end surely doesn't. + */ + return io_tlb_end != 0; +}
