include/linux/shmem_fs.h

   1 #ifndef __SHMEM_FS_H
   2 #define __SHMEM_FS_H
   3
   4 #include <linux/swap.h>
   5 #include <linux/mempolicy.h>
   6 #include <linux/pagemap.h>
   7 #include <linux/percpu_counter.h>
   8
   9 /* inode in-kernel data */
  10
  11 #define SHMEM_NR_DIRECT 16
  12
  13 #define SHMEM_SYMLINK_INLINE_LEN (SHMEM_NR_DIRECT * sizeof(swp_entry_t))
  14
  15 struct shmem_inode_info {
  16         spinlock_t              lock;
  17         unsigned long           flags;
  18         unsigned long           alloced;        /* data pages alloced to file */
  19         unsigned long           swapped;        /* subtotal assigned to swap */
  20         struct shared_policy    policy;         /* NUMA memory alloc policy */
  21         union {
  22                 swp_entry_t     i_direct[SHMEM_NR_DIRECT]; /* first blocks */
  23                 char            inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
  24         };
  25         struct list_head        swaplist;       /* chain of maybes on swap */
  26         struct list_head        xattr_list;     /* list of shmem_xattr */
  27         struct inode            vfs_inode;
  28 };
  29
  30 struct shmem_sb_info {
  31         unsigned long max_blocks;   /* How many blocks are allowed */
  32         struct percpu_counter used_blocks;  /* How many are allocated */
  33         unsigned long max_inodes;   /* How many inodes are allowed */
  34         unsigned long free_inodes;  /* How many are left for allocation */
  35         spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
  36         uid_t uid;                  /* Mount uid for root directory */
  37         gid_t gid;                  /* Mount gid for root directory */
  38         mode_t mode;                /* Mount mode for root directory */
  39         struct mempolicy *mpol;     /* default memory policy for mappings */
  40 };
  41
  42 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
  43 {
  44         return container_of(inode, struct shmem_inode_info, vfs_inode);
  45 }
  46
  47 /*
  48  * Functions in mm/shmem.c called directly from elsewhere:
  49  */
  50 extern int shmem_init(void);
  51 extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
  52 extern struct file *shmem_file_setup(const char *name,
  53                                         loff_t size, unsigned long flags);
  54 extern int shmem_zero_setup(struct vm_area_struct *);
  55 extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  56 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  57                                         pgoff_t index, gfp_t gfp_mask);
  58 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  59 extern int shmem_unuse(swp_entry_t entry, struct page *page);
  60
  61 static inline struct page *shmem_read_mapping_page(
  62                                 struct address_space *mapping, pgoff_t index)
  63 {
  64         return shmem_read_mapping_page_gfp(mapping, index,
  65                                         mapping_gfp_mask(mapping));
  66 }
  67
  68 #endif