From 014bb1de4fc17d54907d54418126a9a9736f4aff Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 9 May 2022 18:20:47 -0700 Subject: mm: create new mm/swap.h header file Patch series "MM changes to improve swap-over-NFS support". Assorted improvements for swap-via-filesystem. This is a resend of these patches, rebased on current HEAD. The only substantial changes is that swap_dirty_folio has replaced swap_set_page_dirty. Currently swap-via-fs (SWP_FS_OPS) doesn't work for any filesystem. It has previously worked for NFS but that broke a few releases back. This series changes to use a new ->swap_rw rather than ->readpage and ->direct_IO. It also makes other improvements. There is a companion series already in linux-next which fixes various issues with NFS. Once both series land, a final patch is needed which changes NFS over to use ->swap_rw. This patch (of 10): Many functions declared in include/linux/swap.h are only used within mm/ Create a new "mm/swap.h" and move some of these declarations there. Remove the redundant 'extern' from the function declarations. [akpm@linux-foundation.org: mm/memory-failure.c needs mm/swap.h] Link: https://lkml.kernel.org/r/164859751830.29473.5309689752169286816.stgit@noble.brown Link: https://lkml.kernel.org/r/164859778120.29473.11725907882296224053.stgit@noble.brown Signed-off-by: NeilBrown Reviewed-by: Christoph Hellwig Tested-by: David Howells Tested-by: Geert Uytterhoeven Cc: Trond Myklebust Cc: Hugh Dickins Cc: Mel Gorman Cc: Miaohe Lin Signed-off-by: Andrew Morton --- mm/swap.h | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 mm/swap.h (limited to 'mm/swap.h') diff --git a/mm/swap.h b/mm/swap.h new file mode 100644 index 000000000000..f8265bf0ce00 --- /dev/null +++ b/mm/swap.h @@ -0,0 +1,133 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _MM_SWAP_H +#define _MM_SWAP_H + +#ifdef CONFIG_SWAP +#include /* for bio_end_io_t */ + +/* linux/mm/page_io.c */ +int swap_readpage(struct page *page, bool do_poll); +int swap_writepage(struct page *page, struct writeback_control *wbc); +void end_swap_bio_write(struct bio *bio); +int __swap_writepage(struct page *page, struct writeback_control *wbc, + bio_end_io_t end_write_func); + +/* 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); +int add_to_swap(struct page *page); +void *get_shadow_from_swap_cache(swp_entry_t entry); +int add_to_swap_cache(struct page *page, swp_entry_t entry, + gfp_t gfp, void **shadowp); +void __delete_from_swap_cache(struct page *page, + swp_entry_t entry, void *shadow); +void delete_from_swap_cache(struct page *page); +void clear_shadow_from_swap_cache(int type, unsigned long begin, + unsigned long end); +void free_swap_cache(struct page *page); +struct page *lookup_swap_cache(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 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); + +#else /* CONFIG_SWAP */ +static inline int swap_readpage(struct page *page, bool do_poll) +{ + return 0; +} + +static inline struct address_space *swap_address_space(swp_entry_t entry) +{ + return NULL; +} + +static inline void free_swap_cache(struct page *page) +{ +} + +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 page *lookup_swap_cache(swp_entry_t swp, + 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 int add_to_swap(struct page *page) +{ + return 0; +} + +static inline void *get_shadow_from_swap_cache(swp_entry_t entry) +{ + return NULL; +} + +static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, + gfp_t gfp_mask, void **shadowp) +{ + return -1; +} + +static inline void __delete_from_swap_cache(struct page *page, + swp_entry_t entry, void *shadow) +{ +} + +static inline void delete_from_swap_cache(struct page *page) +{ +} + +static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, + unsigned long end) +{ +} + +#endif /* CONFIG_SWAP */ +#endif /* _MM_SWAP_H */ -- cgit v1.2.3