mm: rename page_order() to buddy_order()

The current page_order() can only be called on pages in the buddy
allocator.  For compound pages, you have to use compound_order().  This is
confusing and led to a bug, so rename page_order() to buddy_order().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20201001152259.14932-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 15 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3b032dac62e6..ccf615c0627e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -792,7 +792,7 @@ static inline void clear_page_guard(struct zone *zone, struct page *page,
 				unsigned int order, int migratetype) {}
 #endif
 
-static inline void set_page_order(struct page *page, unsigned int order)
+static inline void set_buddy_order(struct page *page, unsigned int order)
 {
 	set_page_private(page, order);
 	__SetPageBuddy(page);
@@ -817,7 +817,7 @@ static inline bool page_is_buddy(struct page *page, struct page *buddy,
 	if (!page_is_guard(buddy) && !PageBuddy(buddy))
 		return false;
 
-	if (page_order(buddy) != order)
+	if (buddy_order(buddy) != order)
 		return false;
 
 	/*
@@ -1059,7 +1059,7 @@ continue_merging:
 	}
 
 done_merging:
-	set_page_order(page, order);
+	set_buddy_order(page, order);
 
 	if (fpi_flags & FPI_TO_TAIL)
 		to_tail = true;
@@ -2178,7 +2178,7 @@ static inline void expand(struct zone *zone, struct page *page,
 			continue;
 
 		add_to_free_list(&page[size], zone, high, migratetype);
-		set_page_order(&page[size], high);
+		set_buddy_order(&page[size], high);
 	}
 }
 
@@ -2392,7 +2392,7 @@ static int move_freepages(struct zone *zone,
 		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
 		VM_BUG_ON_PAGE(page_zone(page) != zone, page);
 
-		order = page_order(page);
+		order = buddy_order(page);
 		move_to_free_list(page, zone, order, migratetype);
 		page += 1 << order;
 		pages_moved += 1 << order;
@@ -2516,7 +2516,7 @@ static inline void boost_watermark(struct zone *zone)
 static void steal_suitable_fallback(struct zone *zone, struct page *page,
 		unsigned int alloc_flags, int start_type, bool whole_block)
 {
-	unsigned int current_order = page_order(page);
+	unsigned int current_order = buddy_order(page);
 	int free_pages, movable_pages, alike_pages;
 	int old_block_type;
 
@@ -8344,7 +8344,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
 		 */
 		if (!page_ref_count(page)) {
 			if (PageBuddy(page))
-				iter += (1 << page_order(page)) - 1;
+				iter += (1 << buddy_order(page)) - 1;
 			continue;
 		}
 
@@ -8557,7 +8557,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 	}
 
 	if (outer_start != start) {
-		order = page_order(pfn_to_page(outer_start));
+		order = buddy_order(pfn_to_page(outer_start));
 
 		/*
 		 * outer_start page could be small order buddy page and
@@ -8782,7 +8782,7 @@ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 
 		BUG_ON(page_count(page));
 		BUG_ON(!PageBuddy(page));
-		order = page_order(page);
+		order = buddy_order(page);
 		del_page_from_free_list(page, zone, order);
 		pfn += (1 << order);
 	}
@@ -8801,7 +8801,7 @@ bool is_free_buddy_page(struct page *page)
 	for (order = 0; order < MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
 
-		if (PageBuddy(page_head) && page_order(page_head) >= order)
+		if (PageBuddy(page_head) && buddy_order(page_head) >= order)
 			break;
 	}
 	spin_unlock_irqrestore(&zone->lock, flags);
@@ -8838,7 +8838,7 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page,
 
 		if (current_buddy != target) {
 			add_to_free_list(current_buddy, zone, high, migratetype);
-			set_page_order(current_buddy, high);
+			set_buddy_order(current_buddy, high);
 			page = next_page;
 		}
 	}
@@ -8858,16 +8858,16 @@ bool take_page_off_buddy(struct page *page)
 	spin_lock_irqsave(&zone->lock, flags);
 	for (order = 0; order < MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
-		int buddy_order = page_order(page_head);
+		int page_order = buddy_order(page_head);
 
-		if (PageBuddy(page_head) && buddy_order >= order) {
+		if (PageBuddy(page_head) && page_order >= order) {
 			unsigned long pfn_head = page_to_pfn(page_head);
 			int migratetype = get_pfnblock_migratetype(page_head,
 								   pfn_head);
 
-			del_page_from_free_list(page_head, zone, buddy_order);
+			del_page_from_free_list(page_head, zone, page_order);
 			break_down_buddy_pages(zone, page_head, page, 0,
-						buddy_order, migratetype);
+						page_order, migratetype);
 			ret = true;
 			break;
 		}