swiotlb: remove swiotlb_max_segment

swiotlb_max_segment has always been a bogus API, so remove it now that
the remaining callers are gone.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

include/linux/swiotlb.h

@@ -121,7 +121,6 @@ static inline bool is_swiotlb_force_bounce(struct device *dev)
 
 void swiotlb_init(bool addressing_limited, unsigned int flags);
 void __init swiotlb_exit(void);
-unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
 bool is_swiotlb_active(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long size);
@@ -140,10 +139,6 @@ static inline bool is_swiotlb_force_bounce(struct device *dev)
 static inline void swiotlb_exit(void)
 {
 }
-static inline unsigned int swiotlb_max_segment(void)
-{
-	return 0;
-}
 static inline size_t swiotlb_max_mapping_size(struct device *dev)
 {
 	return SIZE_MAX;

kernel/dma/swiotlb.c

@@ -156,14 +156,6 @@ setup_io_tlb_npages(char *str)
 }
 early_param("swiotlb", setup_io_tlb_npages);
 
-unsigned int swiotlb_max_segment(void)
-{
-	if (!io_tlb_default_mem.nslabs)
-		return 0;
-	return rounddown(io_tlb_default_mem.nslabs << IO_TLB_SHIFT, PAGE_SIZE);
-}
-EXPORT_SYMBOL_GPL(swiotlb_max_segment);
-
 unsigned long swiotlb_size_or_default(void)
 {
 	return default_nslabs << IO_TLB_SHIFT;