[PATCH 6.6.y 3/5] mm/hugetlb: rename folio_putback_active_hugetlb() to folio_putback_hugetlb()

[Sasha Levin <sashal@kernel.org>]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit b235448e8cab7eea17d164efc7bf55505985ba65 ]

Now that folio_putback_hugetlb() is only called on folios that were
previously isolated through folio_isolate_hugetlb(), let's rename it to
match folio_putback_lru().

Add some kernel doc to clarify how this function is supposed to be used.

Link: https://lkml.kernel.org/r/20250113131611.2554758-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 3c2d42b8ee34 ("mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/hugetlb.h |  4 ++--
 mm/hugetlb.c            | 15 +++++++++++++--
 mm/migrate.c            |  6 +++---
 3 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 851502655e646d..0461616efdbf9b 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -166,7 +166,7 @@ bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list);
 int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
 int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 				bool *migratable_cleared);
-void folio_putback_active_hugetlb(struct folio *folio);
+void folio_putback_hugetlb(struct folio *folio);
 void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason);
 void hugetlb_fix_reserve_counts(struct inode *inode);
 extern struct mutex *hugetlb_fault_mutex_table;
@@ -462,7 +462,7 @@ static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 	return 0;
 }
 
-static inline void folio_putback_active_hugetlb(struct folio *folio)
+static inline void folio_putback_hugetlb(struct folio *folio)
 {
 }
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0c6b34dbe9e133..82e77880b0f3bc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7240,7 +7240,7 @@ __weak unsigned long hugetlb_mask_last_page(struct hstate *h)
  * it is already isolated/non-migratable.
  *
  * On success, an additional folio reference is taken that must be dropped
- * using folio_putback_active_hugetlb() to undo the isolation.
+ * using folio_putback_hugetlb() to undo the isolation.
  *
  * Return: True if isolation worked, otherwise False.
  */
@@ -7292,7 +7292,18 @@ int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 	return ret;
 }
 
-void folio_putback_active_hugetlb(struct folio *folio)
+/**
+ * folio_putback_hugetlb - unisolate a hugetlb folio
+ * @folio: the isolated hugetlb folio
+ *
+ * Putback/un-isolate the hugetlb folio that was previous isolated using
+ * folio_isolate_hugetlb(): marking it non-isolated/migratable and putting it
+ * back onto the active list.
+ *
+ * Will drop the additional folio reference obtained through
+ * folio_isolate_hugetlb().
+ */
+void folio_putback_hugetlb(struct folio *folio)
 {
 	spin_lock_irq(&hugetlb_lock);
 	folio_set_hugetlb_migratable(folio);
diff --git a/mm/migrate.c b/mm/migrate.c
index bd3ab46c989c79..620871d193c7ca 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -151,7 +151,7 @@ void putback_movable_pages(struct list_head *l)
 
 	list_for_each_entry_safe(folio, folio2, l, lru) {
 		if (unlikely(folio_test_hugetlb(folio))) {
-			folio_putback_active_hugetlb(folio);
+			folio_putback_hugetlb(folio);
 			continue;
 		}
 		list_del(&folio->lru);
@@ -1373,7 +1373,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
 
 	if (folio_ref_count(src) == 1) {
 		/* page was freed from under us. So we are done. */
-		folio_putback_active_hugetlb(src);
+		folio_putback_hugetlb(src);
 		return MIGRATEPAGE_SUCCESS;
 	}
 
@@ -1456,7 +1456,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
 	folio_unlock(src);
 out:
 	if (rc == MIGRATEPAGE_SUCCESS)
-		folio_putback_active_hugetlb(src);
+		folio_putback_hugetlb(src);
 	else if (rc != -EAGAIN)
 		list_move_tail(&src->lru, ret);
 
-- 
2.53.0