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         unsigned long           next_index;     /* highest alloced index + 1 */
  21         struct shared_policy    policy;         /* NUMA memory alloc policy */
  22         struct page             *i_indirect;    /* top indirect blocks page */
  23         union {
  24                 swp_entry_t     i_direct[SHMEM_NR_DIRECT]; /* first blocks */
  25                 char            inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
  26         };
  27         struct list_head        swaplist;       /* chain of maybes on swap */
  28         struct list_head        xattr_list;     /* list of shmem_xattr */
  29         struct inode            vfs_inode;
  30 };
  31
  32 struct shmem_sb_info {
  33         unsigned long max_blocks;   /* How many blocks are allowed */
  34         struct percpu_counter used_blocks;  /* How many are allocated */
  35         unsigned long max_inodes;   /* How many inodes are allowed */
  36         unsigned long free_inodes;  /* How many are left for allocation */
  37         spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
  38         uid_t uid;                  /* Mount uid for root directory */
  39         gid_t gid;                  /* Mount gid for root directory */
  40         mode_t mode;                /* Mount mode for root directory */
  41         struct mempolicy *mpol;     /* default memory policy for mappings */
  42 };
  43
  44 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
  45 {
  46         return container_of(inode, struct shmem_inode_info, vfs_inode);
  47 }
  48
  49 /*
  50  * Functions in mm/shmem.c called directly from elsewhere:
  51  */
  52 extern int init_tmpfs(void);
  53 extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
  54 extern struct file *shmem_file_setup(const char *name,
  55                                         loff_t size, unsigned long flags);
  56 extern int shmem_zero_setup(struct vm_area_struct *);
  57 extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  58 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  59                                         pgoff_t index, gfp_t gfp_mask);
  60 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  61 extern int shmem_unuse(swp_entry_t entry, struct page *page);
  62 extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
  63                                         struct page **pagep, swp_entry_t *ent);
  64
  65 static inline struct page *shmem_read_mapping_page(
  66                                 struct address_space *mapping, pgoff_t index)
  67 {
  68         return shmem_read_mapping_page_gfp(mapping, index,
  69                                         mapping_gfp_mask(mapping));
  70 }
  71
  72 #endif