[PATCH mm-unstable 1/8] mm/hugetlb: convert isolate_hugetlb to folios

[Sidhartha Kumar]

Convert isolate_hugetlb() to take in a folio and convert its callers to
pass a folio. Using page_folio() to convert the callers to use a folio is
safe as isolate_hugetlb() operates on a head page.

Also add a folio equivalent of get_page_unless_zero().

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
---
 include/linux/hugetlb.h |  4 ++--
 include/linux/mm.h      |  5 +++++
 mm/gup.c                |  2 +-
 mm/hugetlb.c            | 16 ++++++++--------
 mm/memory-failure.c     |  2 +-
 mm/memory_hotplug.c     |  2 +-
 mm/mempolicy.c          |  2 +-
 mm/migrate.c            |  2 +-
 8 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 551834cd5299..482929b2d044 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -169,7 +169,7 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
 						vm_flags_t vm_flags);
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
 						long freed);
-int isolate_hugetlb(struct page *page, struct list_head *list);
+int isolate_hugetlb(struct folio *folio, struct list_head *list);
 int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison);
 int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 				bool *migratable_cleared);
@@ -374,7 +374,7 @@ static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
 	return NULL;
 }
 
-static inline int isolate_hugetlb(struct page *page, struct list_head *list)
+static inline int isolate_hugetlb(struct folio *folio, struct list_head *list)
 {
 	return -EBUSY;
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e2dd5a37d078..cd8508d728f1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -775,6 +775,11 @@ static inline bool get_page_unless_zero(struct page *page)
 	return page_ref_add_unless(page, 1, 0);
 }
 
+static inline bool get_folio_unless_zero(struct folio *folio)
+{
+	return folio_ref_add_unless(folio, 1, 0);
+}
+
 extern int page_is_ram(unsigned long pfn);
 
 enum {
diff --git a/mm/gup.c b/mm/gup.c
index 5182abaaecde..bdb00b9df89e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1843,7 +1843,7 @@ static unsigned long collect_longterm_unpinnable_pages(
 			continue;
 
 		if (folio_test_hugetlb(folio)) {
-			isolate_hugetlb(&folio->page, movable_page_list);
+			isolate_hugetlb(folio, movable_page_list);
 			continue;
 		}
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0c58f6519b9a..90c6f0402c7b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2781,7 +2781,7 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
 		 * Fail with -EBUSY if not possible.
 		 */
 		spin_unlock_irq(&hugetlb_lock);
-		ret = isolate_hugetlb(&old_folio->page, list);
+		ret = isolate_hugetlb(old_folio, list);
 		spin_lock_irq(&hugetlb_lock);
 		goto free_new;
 	} else if (!folio_test_hugetlb_freed(old_folio)) {
@@ -2856,7 +2856,7 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
 	if (hstate_is_gigantic(h))
 		return -ENOMEM;
 
-	if (folio_ref_count(folio) && !isolate_hugetlb(&folio->page, list))
+	if (folio_ref_count(folio) && !isolate_hugetlb(folio, list))
 		ret = 0;
 	else if (!folio_ref_count(folio))
 		ret = alloc_and_dissolve_hugetlb_folio(h, folio, list);
@@ -7271,19 +7271,19 @@ __weak unsigned long hugetlb_mask_last_page(struct hstate *h)
  * These functions are overwritable if your architecture needs its own
  * behavior.
  */
-int isolate_hugetlb(struct page *page, struct list_head *list)
+int isolate_hugetlb(struct folio *folio, struct list_head *list)
 {
 	int ret = 0;
 
 	spin_lock_irq(&hugetlb_lock);
-	if (!PageHeadHuge(page) ||
-	    !HPageMigratable(page) ||
-	    !get_page_unless_zero(page)) {
+	if (!folio_test_hugetlb(folio) ||
+	    !folio_test_hugetlb_migratable(folio) ||
+	    !get_folio_unless_zero(folio)) {
 		ret = -EBUSY;
 		goto unlock;
 	}
-	ClearHPageMigratable(page);
-	list_move_tail(&page->lru, list);
+	folio_clear_hugetlb_migratable(folio);
+	list_move_tail(&folio->lru, list);
 unlock:
 	spin_unlock_irq(&hugetlb_lock);
 	return ret;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 63d8501001c6..cf60c0fa795c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2438,7 +2438,7 @@ static bool isolate_page(struct page *page, struct list_head *pagelist)
 	bool isolated = false;
 
 	if (PageHuge(page)) {
-		isolated = !isolate_hugetlb(page, pagelist);
+		isolated = !isolate_hugetlb(page_folio(page), pagelist);
 	} else {
 		bool lru = !__PageMovable(page);
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index fd40f7e9f176..a1e8c3e9ab08 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1641,7 +1641,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 
 		if (PageHuge(page)) {
 			pfn = page_to_pfn(head) + compound_nr(head) - 1;
-			isolate_hugetlb(head, &source);
+			isolate_hugetlb(folio, &source);
 			continue;
 		} else if (PageTransHuge(page))
 			pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 61aa9aedb728..4e62b26539c9 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -601,7 +601,7 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
 	/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
 	if (flags & (MPOL_MF_MOVE_ALL) ||
 	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
-		if (isolate_hugetlb(page, qp->pagelist) &&
+		if (isolate_hugetlb(page_folio(page), qp->pagelist) &&
 			(flags & MPOL_MF_STRICT))
 			/*
 			 * Failed to isolate page but allow migrating pages
diff --git a/mm/migrate.c b/mm/migrate.c
index 4aea647a0180..6932b3d5a9dd 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1732,7 +1732,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
 
 	if (PageHuge(page)) {
 		if (PageHead(page)) {
-			err = isolate_hugetlb(page, pagelist);
+			err = isolate_hugetlb(page_folio(page), pagelist);
 			if (!err)
 				err = 1;
 		}
-- 
2.39.0