mm: kmsan: use helper macro offset_in_page()

Use helper macro offset_in_page() to improve code readability.  No
functional modification involved.

Link: https://lkml.kernel.org/r/20230727011612.2721843-3-zhangpeng362@huawei.comSigned-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Marco Elver <elver@google.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/kmsan/hooks.c

@@ -339,7 +339,7 @@ void kmsan_handle_dma(struct page *page, size_t offset, size_t size,
 	 * internal KMSAN checks.
 	 */
 	while (size > 0) {
-		page_offset = addr % PAGE_SIZE;
+		page_offset = offset_in_page(addr);
 		to_go = min(PAGE_SIZE - page_offset, (u64)size);
 		kmsan_handle_dma_page((void *)addr, to_go, dir);
 		addr += to_go;

mm/kmsan/shadow.c

@@ -145,7 +145,7 @@ void *kmsan_get_metadata(void *address, bool is_origin)
 		return NULL;
 	if (!page_has_metadata(page))
 		return NULL;
-	off = addr % PAGE_SIZE;
+	off = offset_in_page(addr);
 
 	return (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off;
 }