[PATCH 1/8] mm: use zone lock guard in reserve_highatomic_pageblock()

[Dmitry Ilvokhin]

Use the newly introduced zone_lock_irqsave lock guard in
reserve_highatomic_pageblock() to replace the explicit lock/unlock and
goto out_unlock pattern with automatic scope-based cleanup.

Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Dmitry Ilvokhin <d@xxxxxxxxxxxx>
---
 include/linux/mmzone_lock.h |  9 +++++++++
 mm/page_alloc.c             | 13 +++++--------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/include/linux/mmzone_lock.h b/include/linux/mmzone_lock.h
index 6bd8b026029f..fe399a4505ba 100644
--- a/include/linux/mmzone_lock.h
+++ b/include/linux/mmzone_lock.h
@@ -97,4 +97,13 @@ static inline void zone_unlock_irq(struct zone *zone)
 	spin_unlock_irq(&zone->_lock);
 }
 
+DEFINE_LOCK_GUARD_1(zone_lock_irqsave, struct zone,
+		zone_lock_irqsave(_T->lock, _T->flags),
+		zone_unlock_irqrestore(_T->lock, _T->flags),
+		unsigned long flags)
+DECLARE_LOCK_GUARD_1_ATTRS(zone_lock_irqsave,
+		__acquires(_T), __releases(*(struct zone **)_T))
+#define class_zone_lock_irqsave_constructor(_T) \
+	WITH_LOCK_GUARD_1_ATTRS(zone_lock_irqsave, _T)
+
 #endif /* _LINUX_MMZONE_LOCK_H */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 75ee81445640..260fb003822a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3407,7 +3407,7 @@ static void reserve_highatomic_pageblock(struct page *page, int order,
 					 struct zone *zone)
 {
 	int mt;
-	unsigned long max_managed, flags;
+	unsigned long max_managed;
 
 	/*
 	 * The number reserved as: minimum is 1 pageblock, maximum is
@@ -3421,29 +3421,26 @@ static void reserve_highatomic_pageblock(struct page *page, int order,
 	if (zone->nr_reserved_highatomic >= max_managed)
 		return;
 
-	zone_lock_irqsave(zone, flags);
+	guard(zone_lock_irqsave)(zone);
 
 	/* Recheck the nr_reserved_highatomic limit under the lock */
 	if (zone->nr_reserved_highatomic >= max_managed)
-		goto out_unlock;
+		return;
 
 	/* Yoink! */
 	mt = get_pageblock_migratetype(page);
 	/* Only reserve normal pageblocks (i.e., they can merge with others) */
 	if (!migratetype_is_mergeable(mt))
-		goto out_unlock;
+		return;
 
 	if (order < pageblock_order) {
 		if (move_freepages_block(zone, page, mt, MIGRATE_HIGHATOMIC) == -1)
-			goto out_unlock;
+			return;
 		zone->nr_reserved_highatomic += pageblock_nr_pages;
 	} else {
 		change_pageblock_range(page, order, MIGRATE_HIGHATOMIC);
 		zone->nr_reserved_highatomic += 1 << order;
 	}
-
-out_unlock:
-	zone_unlock_irqrestore(zone, flags);
 }
 
 /*
-- 
2.47.3