From: Joerg Roedel <[email protected]> The SWIOTLB implementation has a maximum size it can allocate dma-handles for. This needs to be exported so that device drivers don't try to allocate larger chunks.
This is especially important for block device drivers like virtio-blk, that might do DMA through SWIOTLB. Signed-off-by: Joerg Roedel <[email protected]> --- include/linux/swiotlb.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 7c007ed7505f..0bcc80a97036 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -72,6 +72,11 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr) return paddr >= io_tlb_start && paddr < io_tlb_end; } +static inline size_t swiotlb_max_alloc_size(void) +{ + return ((1UL << IO_TLB_SHIFT) * IO_TLB_SEGSIZE); +} + bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir, unsigned long attrs); void __init swiotlb_exit(void); @@ -95,6 +100,13 @@ static inline unsigned int swiotlb_max_segment(void) { return 0; } + +static inline size_t swiotlb_max_alloc_size(void) +{ + /* There is no limit when SWIOTLB isn't used */ + return ~0UL; +} + #endif /* CONFIG_SWIOTLB */ extern void swiotlb_print_info(void); -- 2.17.1
