1 files changed, 42 insertions, 25 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4ec90019c1a4..a2602a8207a6 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -145,38 +145,43 @@ enum {
         SWP_DISCARDABLE = (1 << 2),     /* blkdev supports discard */
         SWP_DISCARDING  = (1 << 3),     /* now discarding a free cluster */
         SWP_SOLIDSTATE  = (1 << 4),     /* blkdev seeks are cheap */
+        SWP_CONTINUED   = (1 << 5),     /* swap_map has count continuation */
                                         /* add others here before... */
         SWP_SCANNING    = (1 << 8),     /* refcount in scan_swap_map */
 };
 
 #define SWAP_CLUSTER_MAX 32
 
-#define SWAP_MAP_MAX    0x7ffe
-#define SWAP_MAP_BAD    0x7fff
-#define SWAP_HAS_CACHE  0x8000          /* There is a swap cache of entry. */
-#define SWAP_COUNT_MASK (~SWAP_HAS_CACHE)
+#define SWAP_MAP_MAX    0x3e    /* Max duplication count, in first swap_map */
+#define SWAP_MAP_BAD    0x3f    /* Note pageblock is bad, in first swap_map */
+#define SWAP_HAS_CACHE  0x40    /* Flag page is cached, in first swap_map */
+#define SWAP_CONT_MAX   0x7f    /* Max count, in each swap_map continuation */
+#define COUNT_CONTINUED 0x80    /* See swap_map continuation for full count */
+#define SWAP_MAP_SHMEM  0xbf    /* Owned by shmem/tmpfs, in first swap_map */
+
 /*
  * The in-memory structure used to track swap areas.
  */
 struct swap_info_struct {
-        unsigned long flags;
-        int prio;                       /* swap priority */
-        int next;                       /* next entry on swap list */
-        struct file *swap_file;
-        struct block_device *bdev;
-        struct list_head extent_list;
-        struct swap_extent *curr_swap_extent;
-        unsigned short *swap_map;
-        unsigned int lowest_bit;
-        unsigned int highest_bit;
+        unsigned long   flags;          /* SWP_USED etc: see above */
+        signed short    prio;           /* swap priority of this type */
+        signed char     type;           /* strange name for an index */
+        signed char     next;           /* next type on the swap list */
+        unsigned int    max;            /* extent of the swap_map */
+        unsigned char *swap_map;        /* vmalloc'ed array of usage counts */
+        unsigned int lowest_bit;        /* index of first free in swap_map */
+        unsigned int highest_bit;       /* index of last free in swap_map */
+        unsigned int pages;             /* total of usable pages of swap */
+        unsigned int inuse_pages;       /* number of those currently in use */
+        unsigned int cluster_next;      /* likely index for next allocation */
+        unsigned int cluster_nr;        /* countdown to next cluster search */
         unsigned int lowest_alloc;      /* while preparing discard cluster */
         unsigned int highest_alloc;     /* while preparing discard cluster */
-        unsigned int cluster_next;
-        unsigned int cluster_nr;
-        unsigned int pages;
-        unsigned int max;
-        unsigned int inuse_pages;
-        unsigned int old_block_size;
+        struct swap_extent *curr_swap_extent;
+        struct swap_extent first_swap_extent;
+        struct block_device *bdev;      /* swap device or bdev of swap file */
+        struct file *swap_file;         /* seldom referenced */
+        unsigned int old_block_size;    /* seldom referenced */
 };
 
 struct swap_list_t {
@@ -273,6 +278,7 @@ extern int scan_unevictable_register_node(struct node *node);
 extern void scan_unevictable_unregister_node(struct node *node);
 
 extern int kswapd_run(int nid);
+extern void kswapd_stop(int nid);
 
 #ifdef CONFIG_MMU
 /* linux/mm/shmem.c */
@@ -309,17 +315,18 @@ extern long total_swap_pages;
 extern void si_swapinfo(struct sysinfo *);
 extern swp_entry_t get_swap_page(void);
 extern swp_entry_t get_swap_page_of_type(int);
-extern void swap_duplicate(swp_entry_t);
-extern int swapcache_prepare(swp_entry_t);
 extern int valid_swaphandles(swp_entry_t, unsigned long *);
+extern int add_swap_count_continuation(swp_entry_t, gfp_t);
+extern void swap_shmem_alloc(swp_entry_t);
+extern int swap_duplicate(swp_entry_t);
+extern int swapcache_prepare(swp_entry_t);
 extern void swap_free(swp_entry_t);
 extern void swapcache_free(swp_entry_t, struct page *page);
 extern int free_swap_and_cache(swp_entry_t);
 extern int swap_type_of(dev_t, sector_t, struct block_device **);
 extern unsigned int count_swap_pages(int, int);
-extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
+extern sector_t map_swap_page(struct page *, struct block_device **);
 extern sector_t swapdev_block(int, pgoff_t);
-extern struct swap_info_struct *get_swap_info_struct(unsigned);
 extern int reuse_swap_page(struct page *);
 extern int try_to_free_swap(struct page *);
 struct backing_dev_info;
@@ -384,8 +391,18 @@ static inline void show_swap_cache_info(void)
 #define free_swap_and_cache(swp)        is_migration_entry(swp)
 #define swapcache_prepare(swp)          is_migration_entry(swp)
 
-static inline void swap_duplicate(swp_entry_t swp)
+static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
 {
+        return 0;
+}
+
+static inline void swap_shmem_alloc(swp_entry_t swp)
+{
+}
+
+static inline int swap_duplicate(swp_entry_t swp)
+{
+        return 0;
 }
 
 static inline void swap_free(swp_entry_t swp)