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