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 #include <linux/fs_parser.h> 12 #include <linux/userfaultfd_k.h> 13 14 /* inode in-kernel data */ 15 16 struct shmem_inode_info { 17 spinlock_t lock; 18 unsigned int seals; /* shmem seals */ 19 unsigned long flags; 20 unsigned long alloced; /* data pages alloced to file */ 21 unsigned long swapped; /* subtotal assigned to swap */ 22 pgoff_t fallocend; /* highest fallocate endindex */ 23 struct list_head shrinklist; /* shrinkable hpage inodes */ 24 struct list_head swaplist; /* chain of maybes on swap */ 25 struct shared_policy policy; /* NUMA memory alloc policy */ 26 struct simple_xattrs xattrs; /* list of xattrs */ 27 atomic_t stop_eviction; /* hold when working on inode */ 28 struct timespec64 i_crtime; /* file creation time */ 29 unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */ 30 struct inode vfs_inode; 31 }; 32 33 #define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE 34 #define SHMEM_FL_USER_MODIFIABLE \ 35 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL) 36 #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL) 37 38 struct shmem_sb_info { 39 unsigned long max_blocks; /* How many blocks are allowed */ 40 struct percpu_counter used_blocks; /* How many are allocated */ 41 unsigned long max_inodes; /* How many inodes are allowed */ 42 unsigned long free_inodes; /* How many are left for allocation */ 43 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 44 umode_t mode; /* Mount mode for root directory */ 45 unsigned char huge; /* Whether to try for hugepages */ 46 kuid_t uid; /* Mount uid for root directory */ 47 kgid_t gid; /* Mount gid for root directory */ 48 bool full_inums; /* If i_ino should be uint or ino_t */ 49 bool noswap; /* ignores VM reclaim / swap requests */ 50 ino_t next_ino; /* The next per-sb inode number to use */ 51 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 52 struct mempolicy *mpol; /* default memory policy for mappings */ 53 spinlock_t shrinklist_lock; /* Protects shrinklist */ 54 struct list_head shrinklist; /* List of shinkable inodes */ 55 unsigned long shrinklist_len; /* Length of shrinklist */ 56 }; 57 58 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 59 { 60 return container_of(inode, struct shmem_inode_info, vfs_inode); 61 } 62 63 /* 64 * Functions in mm/shmem.c called directly from elsewhere: 65 */ 66 extern const struct fs_parameter_spec shmem_fs_parameters[]; 67 extern void shmem_init(void); 68 extern int shmem_init_fs_context(struct fs_context *fc); 69 extern struct file *shmem_file_setup(const char *name, 70 loff_t size, unsigned long flags); 71 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 72 unsigned long flags); 73 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 74 const char *name, loff_t size, unsigned long flags); 75 extern int shmem_zero_setup(struct vm_area_struct *); 76 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 77 unsigned long len, unsigned long pgoff, unsigned long flags); 78 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 79 #ifdef CONFIG_SHMEM 80 extern const struct address_space_operations shmem_aops; 81 static inline bool shmem_mapping(struct address_space *mapping) 82 { 83 return mapping->a_ops == &shmem_aops; 84 } 85 #else 86 static inline bool shmem_mapping(struct address_space *mapping) 87 { 88 return false; 89 } 90 #endif /* CONFIG_SHMEM */ 91 extern void shmem_unlock_mapping(struct address_space *mapping); 92 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 93 pgoff_t index, gfp_t gfp_mask); 94 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 95 int shmem_unuse(unsigned int type); 96 97 extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force, 98 struct mm_struct *mm, unsigned long vm_flags); 99 #ifdef CONFIG_SHMEM 100 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 101 #else 102 static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma) 103 { 104 return 0; 105 } 106 #endif 107 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 108 pgoff_t start, pgoff_t end); 109 110 /* Flag allocation requirements to shmem_get_folio */ 111 enum sgp_type { 112 SGP_READ, /* don't exceed i_size, don't allocate page */ 113 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */ 114 SGP_CACHE, /* don't exceed i_size, may allocate page */ 115 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 116 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 117 }; 118 119 int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, 120 enum sgp_type sgp); 121 struct folio *shmem_read_folio_gfp(struct address_space *mapping, 122 pgoff_t index, gfp_t gfp); 123 124 static inline struct folio *shmem_read_folio(struct address_space *mapping, 125 pgoff_t index) 126 { 127 return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping)); 128 } 129 130 static inline struct page *shmem_read_mapping_page( 131 struct address_space *mapping, pgoff_t index) 132 { 133 return shmem_read_mapping_page_gfp(mapping, index, 134 mapping_gfp_mask(mapping)); 135 } 136 137 static inline bool shmem_file(struct file *file) 138 { 139 if (!IS_ENABLED(CONFIG_SHMEM)) 140 return false; 141 if (!file || !file->f_mapping) 142 return false; 143 return shmem_mapping(file->f_mapping); 144 } 145 146 /* 147 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages 148 * beyond i_size's notion of EOF, which fallocate has committed to reserving: 149 * which split_huge_page() must therefore not delete. This use of a single 150 * "fallocend" per inode errs on the side of not deleting a reservation when 151 * in doubt: there are plenty of cases when it preserves unreserved pages. 152 */ 153 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof) 154 { 155 return max(eof, SHMEM_I(inode)->fallocend); 156 } 157 158 extern bool shmem_charge(struct inode *inode, long pages); 159 extern void shmem_uncharge(struct inode *inode, long pages); 160 161 #ifdef CONFIG_USERFAULTFD 162 #ifdef CONFIG_SHMEM 163 extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd, 164 struct vm_area_struct *dst_vma, 165 unsigned long dst_addr, 166 unsigned long src_addr, 167 uffd_flags_t flags, 168 struct folio **foliop); 169 #else /* !CONFIG_SHMEM */ 170 #define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \ 171 src_addr, flags, foliop) ({ BUG(); 0; }) 172 #endif /* CONFIG_SHMEM */ 173 #endif /* CONFIG_USERFAULTFD */ 174 175 #endif 176