[PATCH v2 01/10] mm: swap: introduce pfn_swap_entry_to_folio()

Kefeng Wang
2023-11-04T03:55:49Z

Introduce a new pfn_swap_entry_to_folio(), it is similar to
pfn_swap_entry_to_page(), but return a folio, which allow us
to completely replace the struct page variables with struct
folio variables.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
include/linux/swapops.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index bff1e8d97de0..85cb84e4be95 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -468,6 +468,19 @@ static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
return p;
}

+static inline struct folio *pfn_swap_entry_to_folio(swp_entry_t entry)
+{
+ struct folio *folio = pfn_folio(swp_offset_pfn(entry));
+
+ /*
+ * Any use of migration entries may only occur while the
+ * corresponding folio is locked
+ */
+ BUG_ON(is_migration_entry(entry) && !folio_test_locked(folio));
+
+ return folio;
+}
+
/*
* A pfn swap entry is a special type of swap entry that always has a pfn stored
* in the swap offset. They are used to represent unaddressable device memory
--
2.27.0