[118/155] mm/page_alloc: simplify page_is_buddy() for better code readability

Commit Message

Andrew Morton April 2, 2020, 4:09 a.m. UTC

From: chenqiwu <[e-mail]>
Subject: mm/page_alloc: simplify page_is_buddy() for better code readability

Simplify page_is_buddy() to reduce the redundant code for better code
readability.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: chenqiwu <[e-mail]>
Reviewed-by: Alexander Duyck <[e-mail]>
Reviewed-by: Matthew Wilcox (Oracle) <[e-mail]>
Reviewed-by: Vlastimil Babka <[e-mail]>
Acked-by: Pankaj Gupta <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |   33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

Patch

--- a/mm/page_alloc.c~mm-page_alloc-simplify-page_is_buddy-for-better-code-readability
+++ a/mm/page_alloc.c
@@ -792,32 +792,25 @@  static inline void set_page_order(struct
  *
  * For recording page's order, we use page_private(page).
  */
-static inline int page_is_buddy(struct page *page, struct page *buddy,
+static inline bool page_is_buddy(struct page *page, struct page *buddy,
 							unsigned int order)
 {
-	if (page_is_guard(buddy) && page_order(buddy) == order) {
-		if (page_zone_id(page) != page_zone_id(buddy))
-			return 0;
+	if (!page_is_guard(buddy) && !PageBuddy(buddy))
+		return false;
 
-		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
+	if (page_order(buddy) != order)
+		return false;
 
-		return 1;
-	}
+	/*
+	 * zone check is done late to avoid uselessly calculating
+	 * zone/node ids for pages that could never merge.
+	 */
+	if (page_zone_id(page) != page_zone_id(buddy))
+		return false;
 
-	if (PageBuddy(buddy) && page_order(buddy) == order) {
-		/*
-		 * zone check is done late to avoid uselessly
-		 * calculating zone/node ids for pages that could
-		 * never merge.
-		 */
-		if (page_zone_id(page) != page_zone_id(buddy))
-			return 0;
+	VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
 
-		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
-
-		return 1;
-	}
-	return 0;
+	return true;
 }
 
 #ifdef CONFIG_COMPACTION