[PATCH 1/3] mm: move offset_in_page() to page_helpers.h

[Thorsten Blum <thorsten.blum@linux.dev>]

Move offset_in_page() out of linux/mm.h so users that only need page
offset calculations can include this lightweight header instead of
pulling in all of linux/mm.h.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 include/linux/mm.h           |  2 +-
 include/linux/page_helpers.h | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/page_helpers.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index af23453e9dbd..bf49e52f749a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -17,6 +17,7 @@
 #include <linux/mm_types.h>
 #include <linux/mmap_lock.h>
 #include <linux/range.h>
+#include <linux/page_helpers.h>
 #include <linux/pfn.h>
 #include <linux/percpu-refcount.h>
 #include <linux/bit_spinlock.h>
@@ -3033,7 +3034,6 @@ static inline void clear_page_pfmemalloc(struct page *page)
  */
 extern void pagefault_out_of_memory(void);
 
-#define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
 #define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))
 
 /*
diff --git a/include/linux/page_helpers.h b/include/linux/page_helpers.h
new file mode 100644
index 000000000000..102a4f3c3868
--- /dev/null
+++ b/include/linux/page_helpers.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_PAGE_HELPERS_H
+#define _LINUX_PAGE_HELPERS_H
+
+#include <asm/page.h>
+
+#define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
+
+#endif /* _LINUX_PAGE_HELPERS_H */