IB/ipath: use offset_in_page macro

Use offset_in_page macro instead of (addr & ~PAGE_MASK).
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rdma/ipath/ipath_user_sdma.c

@@ -239,7 +239,7 @@ static int ipath_user_sdma_num_pages(const struct iovec *iov)
 /* truncate length to page boundary */
 static int ipath_user_sdma_page_length(unsigned long addr, unsigned long len)
 {
-	const unsigned long offset = addr & ~PAGE_MASK;
+	const unsigned long offset = offset_in_page(addr);
 
 	return ((offset + len) > PAGE_SIZE) ? (PAGE_SIZE - offset) : len;
 }
@@ -298,7 +298,7 @@ static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd,
 		dma_addr_t dma_addr =
 			dma_map_page(&dd->pcidev->dev,
 				     pages[j], 0, flen, DMA_TO_DEVICE);
-		unsigned long fofs = addr & ~PAGE_MASK;
+		unsigned long fofs = offset_in_page(addr);
 
 		if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
 			ret = -ENOMEM;