1 files changed, 148 insertions, 0 deletions
diff --git a/mm/swap.h b/mm/swap.h
new file mode 100644
index 000000000..cc08c459c
--- /dev/null
+++ b/mm/swap.h
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MM_SWAP_H
+#define _MM_SWAP_H
+
+#ifdef CONFIG_SWAP
+#include <linux/blk_types.h> /* for bio_end_io_t */
+
+/* linux/mm/page_io.c */
+int sio_pool_init(void);
+struct swap_iocb;
+int swap_readpage(struct page *page, bool do_poll,
+		  struct swap_iocb **plug);
+void __swap_read_unplug(struct swap_iocb *plug);
+static inline void swap_read_unplug(struct swap_iocb *plug)
+{
+	if (unlikely(plug))
+		__swap_read_unplug(plug);
+}
+void swap_write_unplug(struct swap_iocb *sio);
+int swap_writepage(struct page *page, struct writeback_control *wbc);
+int __swap_writepage(struct page *page, struct writeback_control *wbc);
+
+/* linux/mm/swap_state.c */
+/* One swap address space for each 64M swap space */
+#define SWAP_ADDRESS_SPACE_SHIFT	14
+#define SWAP_ADDRESS_SPACE_PAGES	(1 << SWAP_ADDRESS_SPACE_SHIFT)
+extern struct address_space *swapper_spaces[];
+#define swap_address_space(entry)			    \
+	(&swapper_spaces[swp_type(entry)][swp_offset(entry) \
+		>> SWAP_ADDRESS_SPACE_SHIFT])
+
+void show_swap_cache_info(void);
+bool add_to_swap(struct folio *folio);
+void *get_shadow_from_swap_cache(swp_entry_t entry);
+int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
+		      gfp_t gfp, void **shadowp);
+void __delete_from_swap_cache(struct folio *folio,
+			      swp_entry_t entry, void *shadow);
+void delete_from_swap_cache(struct folio *folio);
+void clear_shadow_from_swap_cache(int type, unsigned long begin,
+				  unsigned long end);
+struct folio *swap_cache_get_folio(swp_entry_t entry,
+		struct vm_area_struct *vma, unsigned long addr);
+struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
+
+struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
+				   struct vm_area_struct *vma,
+				   unsigned long addr,
+				   bool do_poll,
+				   struct swap_iocb **plug);
+struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
+				     struct vm_area_struct *vma,
+				     unsigned long addr,
+				     bool *new_page_allocated);
+struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
+				    struct vm_fault *vmf);
+struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
+			      struct vm_fault *vmf);
+
+static inline unsigned int folio_swap_flags(struct folio *folio)
+{
+	return page_swap_info(&folio->page)->flags;
+}
+#else /* CONFIG_SWAP */
+struct swap_iocb;
+static inline int swap_readpage(struct page *page, bool do_poll,
+				struct swap_iocb **plug)
+{
+	return 0;
+}
+static inline void swap_write_unplug(struct swap_iocb *sio)
+{
+}
+
+static inline struct address_space *swap_address_space(swp_entry_t entry)
+{
+	return NULL;
+}
+
+static inline void show_swap_cache_info(void)
+{
+}
+
+static inline struct page *swap_cluster_readahead(swp_entry_t entry,
+				gfp_t gfp_mask, struct vm_fault *vmf)
+{
+	return NULL;
+}
+
+static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
+			struct vm_fault *vmf)
+{
+	return NULL;
+}
+
+static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
+{
+	return 0;
+}
+
+static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
+		struct vm_area_struct *vma, unsigned long addr)
+{
+	return NULL;
+}
+
+static inline
+struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
+{
+	return find_get_page(mapping, index);
+}
+
+static inline bool add_to_swap(struct folio *folio)
+{
+	return false;
+}
+
+static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
+{
+	return NULL;
+}
+
+static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
+					gfp_t gfp_mask, void **shadowp)
+{
+	return -1;
+}
+
+static inline void __delete_from_swap_cache(struct folio *folio,
+					swp_entry_t entry, void *shadow)
+{
+}
+
+static inline void delete_from_swap_cache(struct folio *folio)
+{
+}
+
+static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
+				unsigned long end)
+{
+}
+
+static inline unsigned int folio_swap_flags(struct folio *folio)
+{
+	return 0;
+}
+#endif /* CONFIG_SWAP */
+#endif /* _MM_SWAP_H */