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authorNeilBrown <neilb@suse.de>2022-05-09 18:20:47 -0700
committerakpm <akpm@linux-foundation.org>2022-05-09 18:20:47 -0700
commit014bb1de4fc17d54907d54418126a9a9736f4aff (patch)
tree109d318394d0522baf3018899702e8b3fb17de5a /mm/swap.h
parent17de1e559cf1eb01d5d90afd3064d5a280060f6f (diff)
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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 <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swap.h')
-rw-r--r--mm/swap.h133
1 files changed, 133 insertions, 0 deletions
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 <linux/blk_types.h> /* 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 */