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>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index e6d70a4..def6711 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -427,62 +427,19 @@ extern void kswapd_stop(int nid);
 
 #ifdef CONFIG_SWAP
 
-#include <linux/blk_types.h> /* for bio_end_io_t */
-
-/* linux/mm/page_io.c */
-extern int swap_readpage(struct page *page, bool do_poll);
-extern int swap_writepage(struct page *page, struct writeback_control *wbc);
-extern void end_swap_bio_write(struct bio *bio);
-extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
-       bio_end_io_t end_write_func);
 bool swap_dirty_folio(struct address_space *mapping, struct folio *folio);
-
 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
                unsigned long nr_pages, sector_t start_block);
 int generic_swapfile_activate(struct swap_info_struct *, struct file *,
                sector_t *);
 
-/* 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])
 static inline unsigned long total_swapcache_pages(void)
 {
        return global_node_page_state(NR_SWAPCACHE);
 }
 
-extern void show_swap_cache_info(void);
-extern int add_to_swap(struct page *page);
-extern void *get_shadow_from_swap_cache(swp_entry_t entry);
-extern int add_to_swap_cache(struct page *page, swp_entry_t entry,
-                       gfp_t gfp, void **shadowp);
-extern void __delete_from_swap_cache(struct page *page,
-                       swp_entry_t entry, void *shadow);
-extern void delete_from_swap_cache(struct page *);
-extern void clear_shadow_from_swap_cache(int type, unsigned long begin,
-                               unsigned long end);
-extern void free_swap_cache(struct page *);
 extern void free_page_and_swap_cache(struct page *);
 extern void free_pages_and_swap_cache(struct page **, int);
-extern 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);
-extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
-                       struct vm_area_struct *vma, unsigned long addr,
-                       bool do_poll);
-extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
-                       struct vm_area_struct *vma, unsigned long addr,
-                       bool *new_page_allocated);
-extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
-                               struct vm_fault *vmf);
-extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
-                               struct vm_fault *vmf);
-
 /* linux/mm/swapfile.c */
 extern atomic_long_t nr_swap_pages;
 extern long total_swap_pages;
@@ -535,12 +492,6 @@ static inline void put_swap_device(struct swap_info_struct *si)
 }
 
 #else /* CONFIG_SWAP */
-
-static inline int swap_readpage(struct page *page, bool do_poll)
-{
-       return 0;
-}
-
 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
 {
        return NULL;
@@ -555,11 +506,6 @@ static inline void put_swap_device(struct swap_info_struct *si)
 {
 }
 
-static inline struct address_space *swap_address_space(swp_entry_t entry)
-{
-       return NULL;
-}
-
 #define get_nr_swap_pages()                    0L
 #define total_swap_pages                       0L
 #define total_swapcache_pages()                        0UL
@@ -574,14 +520,6 @@ static inline struct address_space *swap_address_space(swp_entry_t entry)
 #define free_pages_and_swap_cache(pages, nr) \
        release_pages((pages), (nr));
 
-static inline void free_swap_cache(struct page *page)
-{
-}
-
-static inline void show_swap_cache_info(void)
-{
-}
-
 /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
 #define free_swap_and_cache(e) is_pfn_swap_entry(e)
 
@@ -607,65 +545,6 @@ static inline void put_swap_page(struct page *page, swp_entry_t swp)
 {
 }
 
-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)
-{
-}
 
 static inline int page_swapcount(struct page *page)
 {

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a2f44d8..86eae68 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -39,6 +39,7 @@
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
 #include "internal.h"
+#include "swap.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/thp.h>

diff --git a/mm/madvise.c b/mm/madvise.c
index c965fac..b19daed 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -35,6 +35,7 @@
 #include <asm/tlb.h>
 
 #include "internal.h"
+#include "swap.h"
 
 struct madvise_walk_private {
        struct mmu_gather *tlb;

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d180ef9..235c85e 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -67,6 +67,7 @@
 #include <net/sock.h>
 #include <net/ip.h>
 #include "slab.h"
+#include "swap.h"
 
 #include <linux/uaccess.h>
 

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 9711c0e..1d11719 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -59,6 +59,7 @@
 #include <linux/page-isolation.h>
 #include <linux/pagewalk.h>
 #include <linux/shmem_fs.h>
+#include "swap.h"
 #include "internal.h"
 #include "ras/ras_event.h"
 

diff --git a/mm/memory.c b/mm/memory.c
index bca6009..6e9428a 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -86,6 +86,7 @@
 
 #include "pgalloc-track.h"
 #include "internal.h"
+#include "swap.h"
 
 #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.

diff --git a/mm/mincore.c b/mm/mincore.c
index 9122676..f4f6273 100644 (file)
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -20,6 +20,7 @@
 #include <linux/pgtable.h>
 
 #include <linux/uaccess.h>
+#include "swap.h"
 
 static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
                        unsigned long end, struct mm_walk *walk)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f01c71e..e85a0dc 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -81,6 +81,7 @@
 #include "internal.h"
 #include "shuffle.h"
 #include "page_reporting.h"
+#include "swap.h"
 
 /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
 typedef int __bitwise fpi_t;

diff --git a/mm/page_io.c b/mm/page_io.c
index 89fbf3c..4b359e5 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -26,6 +26,7 @@
 #include <linux/uio.h>
 #include <linux/sched/task.h>
 #include <linux/delayacct.h>
+#include "swap.h"
 
 void end_swap_bio_write(struct bio *bio)
 {

diff --git a/mm/shmem.c b/mm/shmem.c
index e504d73..913c0b0 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -38,6 +38,7 @@
 #include <linux/hugetlb.h>
 #include <linux/fs_parser.h>
 #include <linux/swapfile.h>
+#include "swap.h"
 
 static struct vfsmount *shm_mnt;
 

diff --git a/mm/swap.h b/mm/swap.h
new file mode 100644 (file)
index 0000000..f8265bf
--- /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 */

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 0138560..5437dd3 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -23,6 +23,7 @@
 #include <linux/huge_mm.h>
 #include <linux/shmem_fs.h>
 #include "internal.h"
+#include "swap.h"
 
 /*
  * swapper_space is a fiction, retained to simplify the path through

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 7279b2d..f08bf67 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -44,6 +44,7 @@
 #include <asm/tlbflush.h>
 #include <linux/swapops.h>
 #include <linux/swap_cgroup.h>
+#include "swap.h"
 
 static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
                                 unsigned char);

diff --git a/mm/util.c b/mm/util.c
index 3492a9e..f27c796 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -27,6 +27,7 @@
 #include <linux/uaccess.h>
 
 #include "internal.h"
+#include "swap.h"
 
 /**
  * kfree_const - conditionally free memory

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6e255e2..b1b91d5 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -59,6 +59,7 @@
 #include <linux/sched/sysctl.h>
 
 #include "internal.h"
+#include "swap.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/vmscan.h>

diff --git a/mm/zswap.c b/mm/zswap.c
index 3efd8ca..2c5db4c 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -36,6 +36,8 @@
 #include <linux/pagemap.h>
 #include <linux/workqueue.h>
 
+#include "swap.h"
+
 /*********************************
 * statistics
 **********************************/