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        struct inode            vfs_inode;
  25};
  26
  27struct shmem_sb_info {
  28        unsigned long max_blocks;   /* How many blocks are allowed */
  29        struct percpu_counter used_blocks;  /* How many are allocated */
  30        unsigned long max_inodes;   /* How many inodes are allowed */
  31        unsigned long free_inodes;  /* How many are left for allocation */
  32        spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
  33        umode_t mode;               /* Mount mode for root directory */
  34        unsigned char huge;         /* Whether to try for hugepages */
  35        kuid_t uid;                 /* Mount uid for root directory */
  36        kgid_t gid;                 /* Mount gid for root directory */
  37        struct mempolicy *mpol;     /* default memory policy for mappings */
  38        spinlock_t shrinklist_lock;   /* Protects shrinklist */
  39        struct list_head shrinklist;  /* List of shinkable inodes */
  40        unsigned long shrinklist_len; /* Length of shrinklist */
  41};
  42
  43static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
  44{
  45        return container_of(inode, struct shmem_inode_info, vfs_inode);
  46}
  47
  48/*
  49 * Functions in mm/shmem.c called directly from elsewhere:
  50 */
  51extern int shmem_init(void);
  52extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
  53extern struct file *shmem_file_setup(const char *name,
  54                                        loff_t size, unsigned long flags);
  55extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
  56                                            unsigned long flags);
  57extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
  58                const char *name, loff_t size, unsigned long flags);
  59extern int shmem_zero_setup(struct vm_area_struct *);
  60extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
  61                unsigned long len, unsigned long pgoff, unsigned long flags);
  62extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
  63#ifdef CONFIG_SHMEM
  64extern bool shmem_mapping(struct address_space *mapping);
  65#else
  66static inline bool shmem_mapping(struct address_space *mapping)
  67{
  68        return false;
  69}
  70#endif /* CONFIG_SHMEM */
  71extern void shmem_unlock_mapping(struct address_space *mapping);
  72extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
  73                                        pgoff_t index, gfp_t gfp_mask);
  74extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
  75extern int shmem_unuse(swp_entry_t entry, struct page *page);
  76
  77extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
  78extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
  79                                                pgoff_t start, pgoff_t end);
  80
  81/* Flag allocation requirements to shmem_getpage */
  82enum sgp_type {
  83        SGP_READ,       /* don't exceed i_size, don't allocate page */
  84        SGP_CACHE,      /* don't exceed i_size, may allocate page */
  85        SGP_NOHUGE,     /* like SGP_CACHE, but no huge pages */
  86        SGP_HUGE,       /* like SGP_CACHE, huge pages preferred */
  87        SGP_WRITE,      /* may exceed i_size, may allocate !Uptodate page */
  88        SGP_FALLOC,     /* like SGP_WRITE, but make existing page Uptodate */
  89};
  90
  91extern int shmem_getpage(struct inode *inode, pgoff_t index,
  92                struct page **pagep, enum sgp_type sgp);
  93
  94static inline struct page *shmem_read_mapping_page(
  95                                struct address_space *mapping, pgoff_t index)
  96{
  97        return shmem_read_mapping_page_gfp(mapping, index,
  98                                        mapping_gfp_mask(mapping));
  99}
 100
 101static inline bool shmem_file(struct file *file)
 102{
 103        if (!IS_ENABLED(CONFIG_SHMEM))
 104                return false;
 105        if (!file || !file->f_mapping)
 106                return false;
 107        return shmem_mapping(file->f_mapping);
 108}
 109
 110extern bool shmem_charge(struct inode *inode, long pages);
 111extern void shmem_uncharge(struct inode *inode, long pages);
 112
 113#ifdef CONFIG_TMPFS
 114
 115extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
 116
 117#else
 118
 119static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned long a)
 120{
 121        return -EINVAL;
 122}
 123
 124#endif
 125
 126#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
 127extern bool shmem_huge_enabled(struct vm_area_struct *vma);
 128#else
 129static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
 130{
 131        return false;
 132}
 133#endif
 134
 135#ifdef CONFIG_SHMEM
 136extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
 137                                  struct vm_area_struct *dst_vma,
 138                                  unsigned long dst_addr,
 139                                  unsigned long src_addr,
 140                                  struct page **pagep);
 141extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
 142                                    pmd_t *dst_pmd,
 143                                    struct vm_area_struct *dst_vma,
 144                                    unsigned long dst_addr);
 145#else
 146#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
 147                               src_addr, pagep)        ({ BUG(); 0; })
 148#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
 149                                 dst_addr)      ({ BUG(); 0; })
 150#endif
 151
 152#endif
 153