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 struct inode vfs_inode; 29 }; 30 31 struct shmem_sb_info { 32 unsigned long max_blocks; /* How many blocks are allowed */ 33 struct percpu_counter used_blocks; /* How many are allocated */ 34 unsigned long max_inodes; /* How many inodes are allowed */ 35 unsigned long free_inodes; /* How many are left for allocation */ 36 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 37 umode_t mode; /* Mount mode for root directory */ 38 unsigned char huge; /* Whether to try for hugepages */ 39 kuid_t uid; /* Mount uid for root directory */ 40 kgid_t gid; /* Mount gid for root directory */ 41 bool full_inums; /* If i_ino should be uint or ino_t */ 42 ino_t next_ino; /* The next per-sb inode number to use */ 43 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 44 struct mempolicy *mpol; /* default memory policy for mappings */ 45 spinlock_t shrinklist_lock; /* Protects shrinklist */ 46 struct list_head shrinklist; /* List of shinkable inodes */ 47 unsigned long shrinklist_len; /* Length of shrinklist */ 48 }; 49 50 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 51 { 52 return container_of(inode, struct shmem_inode_info, vfs_inode); 53 } 54 55 /* 56 * Functions in mm/shmem.c called directly from elsewhere: 57 */ 58 extern const struct fs_parameter_spec shmem_fs_parameters[]; 59 extern void shmem_init(void); 60 extern int shmem_init_fs_context(struct fs_context *fc); 61 extern struct file *shmem_file_setup(const char *name, 62 loff_t size, unsigned long flags); 63 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 64 unsigned long flags); 65 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 66 const char *name, loff_t size, unsigned long flags); 67 extern int shmem_zero_setup(struct vm_area_struct *); 68 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 69 unsigned long len, unsigned long pgoff, unsigned long flags); 70 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 71 #ifdef CONFIG_SHMEM 72 extern const struct address_space_operations shmem_aops; 73 static inline bool shmem_mapping(struct address_space *mapping) 74 { 75 return mapping->a_ops == &shmem_aops; 76 } 77 #else 78 static inline bool shmem_mapping(struct address_space *mapping) 79 { 80 return false; 81 } 82 #endif /* CONFIG_SHMEM */ 83 extern void shmem_unlock_mapping(struct address_space *mapping); 84 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 85 pgoff_t index, gfp_t gfp_mask); 86 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 87 int shmem_unuse(unsigned int type); 88 89 extern bool shmem_is_huge(struct vm_area_struct *vma, 90 struct inode *inode, pgoff_t index); 91 static inline bool shmem_huge_enabled(struct vm_area_struct *vma) 92 { 93 return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff); 94 } 95 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 96 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 97 pgoff_t start, pgoff_t end); 98 99 /* Flag allocation requirements to shmem_getpage */ 100 enum sgp_type { 101 SGP_READ, /* don't exceed i_size, don't allocate page */ 102 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */ 103 SGP_CACHE, /* don't exceed i_size, may allocate page */ 104 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 105 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 106 }; 107 108 extern int shmem_getpage(struct inode *inode, pgoff_t index, 109 struct page **pagep, enum sgp_type sgp); 110 111 static inline struct page *shmem_read_mapping_page( 112 struct address_space *mapping, pgoff_t index) 113 { 114 return shmem_read_mapping_page_gfp(mapping, index, 115 mapping_gfp_mask(mapping)); 116 } 117 118 static inline bool shmem_file(struct file *file) 119 { 120 if (!IS_ENABLED(CONFIG_SHMEM)) 121 return false; 122 if (!file || !file->f_mapping) 123 return false; 124 return shmem_mapping(file->f_mapping); 125 } 126 127 /* 128 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages 129 * beyond i_size's notion of EOF, which fallocate has committed to reserving: 130 * which split_huge_page() must therefore not delete. This use of a single 131 * "fallocend" per inode errs on the side of not deleting a reservation when 132 * in doubt: there are plenty of cases when it preserves unreserved pages. 133 */ 134 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof) 135 { 136 return max(eof, SHMEM_I(inode)->fallocend); 137 } 138 139 extern bool shmem_charge(struct inode *inode, long pages); 140 extern void shmem_uncharge(struct inode *inode, long pages); 141 142 #ifdef CONFIG_USERFAULTFD 143 #ifdef CONFIG_SHMEM 144 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 145 struct vm_area_struct *dst_vma, 146 unsigned long dst_addr, 147 unsigned long src_addr, 148 bool zeropage, bool wp_copy, 149 struct page **pagep); 150 #else /* !CONFIG_SHMEM */ 151 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ 152 src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; }) 153 #endif /* CONFIG_SHMEM */ 154 #endif /* CONFIG_USERFAULTFD */ 155 156 #endif 157