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 inode vfs_inode; 28 }; 29 30 struct shmem_sb_info { 31 unsigned long max_blocks; /* How many blocks are allowed */ 32 struct percpu_counter used_blocks; /* How many are allocated */ 33 unsigned long max_inodes; /* How many inodes are allowed */ 34 unsigned long free_inodes; /* How many are left for allocation */ 35 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 36 umode_t mode; /* Mount mode for root directory */ 37 unsigned char huge; /* Whether to try for hugepages */ 38 kuid_t uid; /* Mount uid for root directory */ 39 kgid_t gid; /* Mount gid for root directory */ 40 bool full_inums; /* If i_ino should be uint or ino_t */ 41 ino_t next_ino; /* The next per-sb inode number to use */ 42 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 43 struct mempolicy *mpol; /* default memory policy for mappings */ 44 spinlock_t shrinklist_lock; /* Protects shrinklist */ 45 struct list_head shrinklist; /* List of shinkable inodes */ 46 unsigned long shrinklist_len; /* Length of shrinklist */ 47 }; 48 49 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 50 { 51 return container_of(inode, struct shmem_inode_info, vfs_inode); 52 } 53 54 /* 55 * Functions in mm/shmem.c called directly from elsewhere: 56 */ 57 extern const struct fs_parameter_spec shmem_fs_parameters[]; 58 extern int shmem_init(void); 59 extern int shmem_init_fs_context(struct fs_context *fc); 60 extern struct file *shmem_file_setup(const char *name, 61 loff_t size, unsigned long flags); 62 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 63 unsigned long flags); 64 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 65 const char *name, loff_t size, unsigned long flags); 66 extern int shmem_zero_setup(struct vm_area_struct *); 67 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 68 unsigned long len, unsigned long pgoff, unsigned long flags); 69 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 70 #ifdef CONFIG_SHMEM 71 extern const struct address_space_operations shmem_aops; 72 static inline bool shmem_mapping(struct address_space *mapping) 73 { 74 return mapping->a_ops == &shmem_aops; 75 } 76 #else 77 static inline bool shmem_mapping(struct address_space *mapping) 78 { 79 return false; 80 } 81 #endif /* CONFIG_SHMEM */ 82 extern void shmem_unlock_mapping(struct address_space *mapping); 83 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 84 pgoff_t index, gfp_t gfp_mask); 85 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 86 int shmem_unuse(unsigned int type); 87 88 extern bool shmem_is_huge(struct vm_area_struct *vma, 89 struct inode *inode, pgoff_t index); 90 static inline bool shmem_huge_enabled(struct vm_area_struct *vma) 91 { 92 return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff); 93 } 94 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 95 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 96 pgoff_t start, pgoff_t end); 97 98 /* Flag allocation requirements to shmem_getpage */ 99 enum sgp_type { 100 SGP_READ, /* don't exceed i_size, don't allocate page */ 101 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */ 102 SGP_CACHE, /* don't exceed i_size, may allocate page */ 103 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 104 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 105 }; 106 107 extern int shmem_getpage(struct inode *inode, pgoff_t index, 108 struct page **pagep, enum sgp_type sgp); 109 110 static inline struct page *shmem_read_mapping_page( 111 struct address_space *mapping, pgoff_t index) 112 { 113 return shmem_read_mapping_page_gfp(mapping, index, 114 mapping_gfp_mask(mapping)); 115 } 116 117 static inline bool shmem_file(struct file *file) 118 { 119 if (!IS_ENABLED(CONFIG_SHMEM)) 120 return false; 121 if (!file || !file->f_mapping) 122 return false; 123 return shmem_mapping(file->f_mapping); 124 } 125 126 /* 127 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages 128 * beyond i_size's notion of EOF, which fallocate has committed to reserving: 129 * which split_huge_page() must therefore not delete. This use of a single 130 * "fallocend" per inode errs on the side of not deleting a reservation when 131 * in doubt: there are plenty of cases when it preserves unreserved pages. 132 */ 133 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof) 134 { 135 return max(eof, SHMEM_I(inode)->fallocend); 136 } 137 138 extern bool shmem_charge(struct inode *inode, long pages); 139 extern void shmem_uncharge(struct inode *inode, long pages); 140 141 #ifdef CONFIG_USERFAULTFD 142 #ifdef CONFIG_SHMEM 143 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 144 struct vm_area_struct *dst_vma, 145 unsigned long dst_addr, 146 unsigned long src_addr, 147 bool zeropage, 148 struct page **pagep); 149 #else /* !CONFIG_SHMEM */ 150 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ 151 src_addr, zeropage, pagep) ({ BUG(); 0; }) 152 #endif /* CONFIG_SHMEM */ 153 #endif /* CONFIG_USERFAULTFD */ 154 155 #endif 156