LXR linux/include/linux/shmem

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __SHMEM_FS_H
   3#define __SHMEM_FS_H
   4
   5#include <linux/file.h>
   6#include <linux/swap.h>
   7#include <linux/mempolicy.h>
   8#include <linux/pagemap.h>
   9#include <linux/percpu_counter.h>
  10#include <linux/xattr.h>
  11
  12/* inode in-kernel data */
  13
  14struct shmem_inode_info {
  15        spinlock_t              lock;
  16        unsigned int            seals;          /* shmem seals */
  17        unsigned long           flags;
  18        unsigned long           alloced;        /* data pages alloced to file */
  19        unsigned long           swapped;        /* subtotal assigned to swap */
  20        struct list_head        shrinklist;     /* shrinkable hpage inodes */
  21        struct list_head        swaplist;       /* chain of maybes on swap */
  22        struct shared_policy    policy;         /* NUMA memory alloc policy */
  23        struct simple_xattrs    xattrs;         /* list of xattrs */
  24        atomic_t                stop_eviction;  /* hold when working on inode */
  25        struct inode            vfs_inode;
  26};
  27
  28struct shmem_sb_info {
  29        unsigned long max_blocks;   /* How many blocks are allowed */
  30        struct percpu_counter used_blocks;  /* How many are allocated */
  31        unsigned long max_inodes;   /* How many inodes are allowed */
  32        unsigned long free_inodes;  /* How many are left for allocation */
  33        spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
  34        umode_t mode;               /* Mount mode for root directory */
  35        unsigned char huge;         /* Whether to try for hugepages */
  36        kuid_t uid;                 /* Mount uid for root directory */
  37        kgid_t gid;                 /* Mount gid for root directory */
  38        struct mempolicy *mpol;     /* default memory policy for mappings */
  39        spinlock_t shrinklist_lock;   /* Protects shrinklist */
  40        struct list_head shrinklist;  /* List of shinkable inodes */
  41        unsigned long shrinklist_len; /* Length of shrinklist */
  42};
  43
  44static 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 */
  52extern int shmem_init(void);
  53extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
  54extern struct file *shmem_file_setup(const char *name,
  55                                        loff_t size, unsigned long flags);
  56extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
  57                                            unsigned long flags);
  58extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
  59                const char *name, loff_t size, unsigned long flags);
  60extern int shmem_zero_setup(struct vm_area_struct *);
  61extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
  62                unsigned long len, unsigned long pgoff, unsigned long flags);
  63extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  64#ifdef CONFIG_SHMEM
  65extern bool shmem_mapping(struct address_space *mapping);
  66#else
  67static inline bool shmem_mapping(struct address_space *mapping)
  68{
  69        return false;
  70}
  71#endif /* CONFIG_SHMEM */
  72extern void shmem_unlock_mapping(struct address_space *mapping);
  73extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  74                                        pgoff_t index, gfp_t gfp_mask);
  75extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  76extern int shmem_unuse(unsigned int type, bool frontswap,
  77                       unsigned long *fs_pages_to_unuse);
  78
  79extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
  80extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
  81                                                pgoff_t start, pgoff_t end);
  82
  83/* Flag allocation requirements to shmem_getpage */
  84enum sgp_type {
  85        SGP_READ,       /* don't exceed i_size, don't allocate page */
  86        SGP_CACHE,      /* don't exceed i_size, may allocate page */
  87        SGP_NOHUGE,     /* like SGP_CACHE, but no huge pages */
  88        SGP_HUGE,       /* like SGP_CACHE, huge pages preferred */
  89        SGP_WRITE,      /* may exceed i_size, may allocate !Uptodate page */
  90        SGP_FALLOC,     /* like SGP_WRITE, but make existing page Uptodate */
  91};
  92
  93extern int shmem_getpage(struct inode *inode, pgoff_t index,
  94                struct page **pagep, enum sgp_type sgp);
  95
  96static inline struct page *shmem_read_mapping_page(
  97                                struct address_space *mapping, pgoff_t index)
  98{
  99        return shmem_read_mapping_page_gfp(mapping, index,
 100                                        mapping_gfp_mask(mapping));
 101}
 102
 103static inline bool shmem_file(struct file *file)
 104{
 105        if (!IS_ENABLED(CONFIG_SHMEM))
 106                return false;
 107        if (!file || !file->f_mapping)
 108                return false;
 109        return shmem_mapping(file->f_mapping);
 110}
 111
 112extern bool shmem_charge(struct inode *inode, long pages);
 113extern void shmem_uncharge(struct inode *inode, long pages);
 114
 115#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
 116extern bool shmem_huge_enabled(struct vm_area_struct *vma);
 117#else
 118static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
 119{
 120        return false;
 121}
 122#endif
 123
 124#ifdef CONFIG_SHMEM
 125extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
 126                                  struct vm_area_struct *dst_vma,
 127                                  unsigned long dst_addr,
 128                                  unsigned long src_addr,
 129                                  struct page **pagep);
 130extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
 131                                    pmd_t *dst_pmd,
 132                                    struct vm_area_struct *dst_vma,
 133                                    unsigned long dst_addr);
 134#else
 135#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
 136                               src_addr, pagep)        ({ BUG(); 0; })
 137#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
 138                                 dst_addr)      ({ BUG(); 0; })
 139#endif
 140
 141#endif
 142