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 \ 34 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL) 35 #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL) 36 37 struct shmem_sb_info { 38 unsigned long max_blocks; /* How many blocks are allowed */ 39 struct percpu_counter used_blocks; /* How many are allocated */ 40 unsigned long max_inodes; /* How many inodes are allowed */ 41 unsigned long free_inodes; /* How many are left for allocation */ 42 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 43 umode_t mode; /* Mount mode for root directory */ 44 unsigned char huge; /* Whether to try for hugepages */ 45 kuid_t uid; /* Mount uid for root directory */ 46 kgid_t gid; /* Mount gid for root directory */ 47 bool full_inums; /* If i_ino should be uint or ino_t */ 48 ino_t next_ino; /* The next per-sb inode number to use */ 49 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 50 struct mempolicy *mpol; /* default memory policy for mappings */ 51 spinlock_t shrinklist_lock; /* Protects shrinklist */ 52 struct list_head shrinklist; /* List of shinkable inodes */ 53 unsigned long shrinklist_len; /* Length of shrinklist */ 54 }; 55 56 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 57 { 58 return container_of(inode, struct shmem_inode_info, vfs_inode); 59 } 60 61 /* 62 * Functions in mm/shmem.c called directly from elsewhere: 63 */ 64 extern const struct fs_parameter_spec shmem_fs_parameters[]; 65 extern void shmem_init(void); 66 extern int shmem_init_fs_context(struct fs_context *fc); 67 extern struct file *shmem_file_setup(const char *name, 68 loff_t size, unsigned long flags); 69 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 70 unsigned long flags); 71 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 72 const char *name, loff_t size, unsigned long flags); 73 extern int shmem_zero_setup(struct vm_area_struct *); 74 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 75 unsigned long len, unsigned long pgoff, unsigned long flags); 76 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 77 #ifdef CONFIG_SHMEM 78 extern const struct address_space_operations shmem_aops; 79 static inline bool shmem_mapping(struct address_space *mapping) 80 { 81 return mapping->a_ops == &shmem_aops; 82 } 83 #else 84 static inline bool shmem_mapping(struct address_space *mapping) 85 { 86 return false; 87 } 88 #endif /* CONFIG_SHMEM */ 89 extern void shmem_unlock_mapping(struct address_space *mapping); 90 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 91 pgoff_t index, gfp_t gfp_mask); 92 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 93 int shmem_unuse(unsigned int type); 94 95 extern bool shmem_is_huge(struct vm_area_struct *vma, 96 struct inode *inode, pgoff_t index); 97 static inline bool shmem_huge_enabled(struct vm_area_struct *vma) 98 { 99 return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff); 100 } 101 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 102 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 103 pgoff_t start, pgoff_t end); 104 105 /* Flag allocation requirements to shmem_getpage */ 106 enum sgp_type { 107 SGP_READ, /* don't exceed i_size, don't allocate page */ 108 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */ 109 SGP_CACHE, /* don't exceed i_size, may allocate page */ 110 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 111 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 112 }; 113 114 extern int shmem_getpage(struct inode *inode, pgoff_t index, 115 struct page **pagep, enum sgp_type sgp); 116 117 static inline struct page *shmem_read_mapping_page( 118 struct address_space *mapping, pgoff_t index) 119 { 120 return shmem_read_mapping_page_gfp(mapping, index, 121 mapping_gfp_mask(mapping)); 122 } 123 124 static inline bool shmem_file(struct file *file) 125 { 126 if (!IS_ENABLED(CONFIG_SHMEM)) 127 return false; 128 if (!file || !file->f_mapping) 129 return false; 130 return shmem_mapping(file->f_mapping); 131 } 132 133 /* 134 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages 135 * beyond i_size's notion of EOF, which fallocate has committed to reserving: 136 * which split_huge_page() must therefore not delete. This use of a single 137 * "fallocend" per inode errs on the side of not deleting a reservation when 138 * in doubt: there are plenty of cases when it preserves unreserved pages. 139 */ 140 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof) 141 { 142 return max(eof, SHMEM_I(inode)->fallocend); 143 } 144 145 extern bool shmem_charge(struct inode *inode, long pages); 146 extern void shmem_uncharge(struct inode *inode, long pages); 147 148 #ifdef CONFIG_USERFAULTFD 149 #ifdef CONFIG_SHMEM 150 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 151 struct vm_area_struct *dst_vma, 152 unsigned long dst_addr, 153 unsigned long src_addr, 154 bool zeropage, bool wp_copy, 155 struct page **pagep); 156 #else /* !CONFIG_SHMEM */ 157 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ 158 src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; }) 159 #endif /* CONFIG_SHMEM */ 160 #endif /* CONFIG_USERFAULTFD */ 161 162 #endif 163