include/linux/shmem_fs.h

   1 #ifndef __SHMEM_FS_H
   2 #define __SHMEM_FS_H
   3
   4 #include <linux/file.h>
   5 #include <linux/swap.h>
   6 #include <linux/mempolicy.h>
   7 #include <linux/pagemap.h>
   8 #include <linux/percpu_counter.h>
   9 #include <linux/xattr.h>
  10
  11 /* inode in-kernel data */
  12
  13 struct shmem_inode_info {
  14         spinlock_t              lock;
  15         unsigned int            seals;          /* shmem seals */
  16         unsigned long           flags;
  17         unsigned long           alloced;        /* data pages alloced to file */
  18         unsigned long           swapped;        /* subtotal assigned to swap */
  19         struct list_head        shrinklist;     /* shrinkable hpage inodes */
  20         struct list_head        swaplist;       /* chain of maybes on swap */
  21         struct shared_policy    policy;         /* NUMA memory alloc policy */
  22         struct simple_xattrs    xattrs;         /* list of xattrs */
  23         struct inode            vfs_inode;
  24 };
  25
  26 struct shmem_sb_info {
  27         unsigned long max_blocks;   /* How many blocks are allowed */
  28         struct percpu_counter used_blocks;  /* How many are allocated */
  29         unsigned long max_inodes;   /* How many inodes are allowed */
  30         unsigned long free_inodes;  /* How many are left for allocation */
  31         spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
  32         umode_t mode;               /* Mount mode for root directory */
  33         unsigned char huge;         /* Whether to try for hugepages */
  34         kuid_t uid;                 /* Mount uid for root directory */
  35         kgid_t gid;                 /* Mount gid for root directory */
  36         struct mempolicy *mpol;     /* default memory policy for mappings */
  37         spinlock_t shrinklist_lock;   /* Protects shrinklist */
  38         struct list_head shrinklist;  /* List of shinkable inodes */
  39         unsigned long shrinklist_len; /* Length of shrinklist */
  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 struct file *shmem_kernel_file_setup(const char *name, loff_t size,
  55                                             unsigned long flags);
  56 extern int shmem_zero_setup(struct vm_area_struct *);
  57 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
  58                 unsigned long len, unsigned long pgoff, unsigned long flags);
  59 extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  60 #ifdef CONFIG_SHMEM
  61 extern bool shmem_mapping(struct address_space *mapping);
  62 #else
  63 static inline bool shmem_mapping(struct address_space *mapping)
  64 {
  65         return false;
  66 }
  67 #endif /* CONFIG_SHMEM */
  68 extern void shmem_unlock_mapping(struct address_space *mapping);
  69 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  70                                         pgoff_t index, gfp_t gfp_mask);
  71 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  72 extern int shmem_unuse(swp_entry_t entry, struct page *page);
  73
  74 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
  75 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
  76                                                 pgoff_t start, pgoff_t end);
  77
  78 /* Flag allocation requirements to shmem_getpage */
  79 enum sgp_type {
  80         SGP_READ,       /* don't exceed i_size, don't allocate page */
  81         SGP_CACHE,      /* don't exceed i_size, may allocate page */
  82         SGP_NOHUGE,     /* like SGP_CACHE, but no huge pages */
  83         SGP_HUGE,       /* like SGP_CACHE, huge pages preferred */
  84         SGP_WRITE,      /* may exceed i_size, may allocate !Uptodate page */
  85         SGP_FALLOC,     /* like SGP_WRITE, but make existing page Uptodate */
  86 };
  87
  88 extern int shmem_getpage(struct inode *inode, pgoff_t index,
  89                 struct page **pagep, enum sgp_type sgp);
  90
  91 static inline struct page *shmem_read_mapping_page(
  92                                 struct address_space *mapping, pgoff_t index)
  93 {
  94         return shmem_read_mapping_page_gfp(mapping, index,
  95                                         mapping_gfp_mask(mapping));
  96 }
  97
  98 static inline bool shmem_file(struct file *file)
  99 {
 100         if (!IS_ENABLED(CONFIG_SHMEM))
 101                 return false;
 102         if (!file || !file->f_mapping)
 103                 return false;
 104         return shmem_mapping(file->f_mapping);
 105 }
 106
 107 extern bool shmem_charge(struct inode *inode, long pages);
 108 extern void shmem_uncharge(struct inode *inode, long pages);
 109
 110 #ifdef CONFIG_TMPFS
 111
 112 extern int shmem_add_seals(struct file *file, unsigned int seals);
 113 extern int shmem_get_seals(struct file *file);
 114 extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
 115
 116 #else
 117
 118 static inline long shmem_fcntl(struct file *f, unsigned int c, unsigned long a)
 119 {
 120         return -EINVAL;
 121 }
 122
 123 #endif
 124
 125 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
 126 extern bool shmem_huge_enabled(struct vm_area_struct *vma);
 127 #else
 128 static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
 129 {
 130         return false;
 131 }
 132 #endif
 133
 134 #ifdef CONFIG_SHMEM
 135 extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
 136                                   struct vm_area_struct *dst_vma,
 137                                   unsigned long dst_addr,
 138                                   unsigned long src_addr,
 139                                   struct page **pagep);
 140 #else
 141 #define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
 142                                src_addr, pagep)        ({ BUG(); 0; })
 143 #endif
 144
 145 #endif