From: Dmitry Ilvokhin <d@ilvokhin.com>
Date: Wed, 29 Apr 2026 12:02:09 +0000 (+0000)
Subject: mm: use zone lock guard in set_migratetype_isolate()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=feb0df835fde31ba6af7ab2b7b05751cadc97472;p=thirdparty%2Fkernel%2Fstable.git

mm: use zone lock guard in set_migratetype_isolate()

Use spinlock_irqsave scoped lock guard in set_migratetype_isolate() to
replace the explicit lock/unlock pattern with automatic scope-based
cleanup.  The scoped variant is used to keep dump_page() outside the
locked section to avoid a lockdep splat.

Link: https://lore.kernel.org/6883351ad7f74d20875fff30e0e3214a089cea97.1777462630.git.d@ilvokhin.com
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 9d606052dd80..7a9d631945a3 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -167,48 +167,40 @@ static int set_migratetype_isolate(struct page *page, enum pb_isolate_mode mode,
 {
 	struct zone *zone = page_zone(page);
 	struct page *unmovable;
-	unsigned long flags;
 	unsigned long check_unmovable_start, check_unmovable_end;
 
 	if (PageUnaccepted(page))
 		accept_page(page);
 
-	spin_lock_irqsave(&zone->lock, flags);
-
-	/*
-	 * We assume the caller intended to SET migrate type to isolate.
-	 * If it is already set, then someone else must have raced and
-	 * set it before us.
-	 */
-	if (is_migrate_isolate_page(page)) {
-		spin_unlock_irqrestore(&zone->lock, flags);
-		return -EBUSY;
-	}
-
-	/*
-	 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
-	 * We just check MOVABLE pages.
-	 *
-	 * Pass the intersection of [start_pfn, end_pfn) and the page's pageblock
-	 * to avoid redundant checks.
-	 */
-	check_unmovable_start = max(page_to_pfn(page), start_pfn);
-	check_unmovable_end = min(pageblock_end_pfn(page_to_pfn(page)),
-				  end_pfn);
-
-	unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
-			mode);
-	if (!unmovable) {
-		if (!pageblock_isolate_and_move_free_pages(zone, page)) {
-			spin_unlock_irqrestore(&zone->lock, flags);
+	scoped_guard(spinlock_irqsave, &zone->lock) {
+		/*
+		 * We assume the caller intended to SET migrate type to
+		 * isolate. If it is already set, then someone else must have
+		 * raced and set it before us.
+		 */
+		if (is_migrate_isolate_page(page))
 			return -EBUSY;
+
+		/*
+		 * FIXME: Now, memory hotplug doesn't call shrink_slab() by
+		 * itself. We just check MOVABLE pages.
+		 *
+		 * Pass the intersection of [start_pfn, end_pfn) and the page's
+		 * pageblock to avoid redundant checks.
+		 */
+		check_unmovable_start = max(page_to_pfn(page), start_pfn);
+		check_unmovable_end = min(pageblock_end_pfn(page_to_pfn(page)),
+					  end_pfn);
+
+		unmovable = has_unmovable_pages(check_unmovable_start,
+				check_unmovable_end, mode);
+		if (!unmovable) {
+			if (!pageblock_isolate_and_move_free_pages(zone, page))
+				return -EBUSY;
+			zone->nr_isolate_pageblock++;
+			return 0;
 		}
-		zone->nr_isolate_pageblock++;
-		spin_unlock_irqrestore(&zone->lock, flags);
-		return 0;
 	}
-
-	spin_unlock_irqrestore(&zone->lock, flags);
 	if (mode == PB_ISOLATE_MODE_MEM_OFFLINE) {
 		/*
 		 * printk() with zone->lock held will likely trigger a