alloc_tag: outline and export free_reserved_page()

Outline and export free_reserved_page() because modules use it and it in
turn uses page_ext_{get|put} which should not be exported.  The same
result could be obtained by outlining {get|put}_page_tag_ref() but that
would have higher performance impact as these functions are used in more
performance critical paths.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: dcfe378 ("lib: introduce support for page allocation tagging")
Signed-off-by: Suren Baghdasaryan <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Suggested-by: Christoph Hellwig <[email protected]>
Suggested-by: Vlastimil Babka <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Sourav Panda <[email protected]>
Cc: <[email protected]>	[6.10]
Signed-off-by: Andrew Morton <[email protected]>

include/linux/mm.h

@@ -3137,21 +3137,7 @@ extern void reserve_bootmem_region(phys_addr_t start,
 				   phys_addr_t end, int nid);
 
 /* Free the reserved page into the buddy system, so it gets managed. */
-static inline void free_reserved_page(struct page *page)
-{
-	if (mem_alloc_profiling_enabled()) {
-		union codetag_ref *ref = get_page_tag_ref(page);
-
-		if (ref) {
-			set_codetag_empty(ref);
-			put_page_tag_ref(ref);
-		}
-	}
-	ClearPageReserved(page);
-	init_page_count(page);
-	__free_page(page);
-	adjust_managed_page_count(page, 1);
-}
+void free_reserved_page(struct page *page);
 #define free_highmem_page(page) free_reserved_page(page)
 
 static inline void mark_page_reserved(struct page *page)

mm/page_alloc.c

@@ -5815,6 +5815,23 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
 	return pages;
 }
 
+void free_reserved_page(struct page *page)
+{
+	if (mem_alloc_profiling_enabled()) {
+		union codetag_ref *ref = get_page_tag_ref(page);
+
+		if (ref) {
+			set_codetag_empty(ref);
+			put_page_tag_ref(ref);
+		}
+	}
+	ClearPageReserved(page);
+	init_page_count(page);
+	__free_page(page);
+	adjust_managed_page_count(page, 1);
+}
+EXPORT_SYMBOL(free_reserved_page);
+
 static int page_alloc_cpu_dead(unsigned int cpu)
 {
 	struct zone *zone;