dma-mapping: use offset_in_page macro

Use offset_in_page macro instead of (addr & ~PAGE_MASK).
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/dma-mapping.h

@@ -129,10 +129,10 @@ static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
 	kmemcheck_mark_initialized(ptr, size);
 	BUG_ON(!valid_dma_direction(dir));
 	addr = ops->map_page(dev, virt_to_page(ptr),
-			     (unsigned long)ptr & ~PAGE_MASK, size,
+			     offset_in_page(ptr), size,
 			     dir, attrs);
 	debug_dma_map_page(dev, virt_to_page(ptr),
-			   (unsigned long)ptr & ~PAGE_MASK, size,
+			   offset_in_page(ptr), size,
 			   dir, addr, true);
 	return addr;
 }