LXR linux/include/linux/shmem

   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
  13struct 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
  26struct 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
  42static 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 */
  50extern int shmem_init(void);
  51extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
  52extern struct file *shmem_file_setup(const char *name,
  53                                        loff_t size, unsigned long flags);
  54extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
  55                                            unsigned long flags);
  56extern int shmem_zero_setup(struct vm_area_struct *);
  57extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
  58                unsigned long len, unsigned long pgoff, unsigned long flags);
  59extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  60#ifdef CONFIG_SHMEM
  61extern bool shmem_mapping(struct address_space *mapping);
  62#else
  63static inline bool shmem_mapping(struct address_space *mapping)
  64{
  65        return false;
  66}
  67#endif /* CONFIG_SHMEM */
  68extern void shmem_unlock_mapping(struct address_space *mapping);
  69extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  70                                        pgoff_t index, gfp_t gfp_mask);
  71extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  72extern int shmem_unuse(swp_entry_t entry, struct page *page);
  73
  74extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
  75extern 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 */
  79enum 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
  88extern int shmem_getpage(struct inode *inode, pgoff_t index,
  89                struct page **pagep, enum sgp_type sgp);
  90
  91static 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
  98static 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
 107extern bool shmem_charge(struct inode *inode, long pages);
 108extern void shmem_uncharge(struct inode *inode, long pages);
 109
 110#ifdef CONFIG_TMPFS
 111
 112extern int shmem_add_seals(struct file *file, unsigned int seals);
 113extern int shmem_get_seals(struct file *file);
 114extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
 115
 116#else
 117
 118static 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
 126extern bool shmem_huge_enabled(struct vm_area_struct *vma);
 127#else
 128static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
 129{
 130        return false;
 131}
 132#endif
 133
 134#ifdef CONFIG_SHMEM
 135extern 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
 146