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 struct list_head shrinklist; /* shrinkable hpage inodes */ 22 struct list_head swaplist; /* chain of maybes on swap */ 23 struct shared_policy policy; /* NUMA memory alloc policy */ 24 struct simple_xattrs xattrs; /* list of xattrs */ 25 atomic_t stop_eviction; /* hold when working on inode */ 26 struct inode vfs_inode; 27 }; 28 29 struct shmem_sb_info { 30 unsigned long max_blocks; /* How many blocks are allowed */ 31 struct percpu_counter used_blocks; /* How many are allocated */ 32 unsigned long max_inodes; /* How many inodes are allowed */ 33 unsigned long free_inodes; /* How many are left for allocation */ 34 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 35 umode_t mode; /* Mount mode for root directory */ 36 unsigned char huge; /* Whether to try for hugepages */ 37 kuid_t uid; /* Mount uid for root directory */ 38 kgid_t gid; /* Mount gid for root directory */ 39 bool full_inums; /* If i_ino should be uint or ino_t */ 40 ino_t next_ino; /* The next per-sb inode number to use */ 41 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 42 struct mempolicy *mpol; /* default memory policy for mappings */ 43 spinlock_t shrinklist_lock; /* Protects shrinklist */ 44 struct list_head shrinklist; /* List of shinkable inodes */ 45 unsigned long shrinklist_len; /* Length of shrinklist */ 46 }; 47 48 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 49 { 50 return container_of(inode, struct shmem_inode_info, vfs_inode); 51 } 52 53 /* 54 * Functions in mm/shmem.c called directly from elsewhere: 55 */ 56 extern const struct fs_parameter_spec shmem_fs_parameters[]; 57 extern int shmem_init(void); 58 extern int shmem_init_fs_context(struct fs_context *fc); 59 extern struct file *shmem_file_setup(const char *name, 60 loff_t size, unsigned long flags); 61 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 62 unsigned long flags); 63 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 64 const char *name, loff_t size, unsigned long flags); 65 extern int shmem_zero_setup(struct vm_area_struct *); 66 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 67 unsigned long len, unsigned long pgoff, unsigned long flags); 68 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 69 #ifdef CONFIG_SHMEM 70 extern const struct address_space_operations shmem_aops; 71 static inline bool shmem_mapping(struct address_space *mapping) 72 { 73 return mapping->a_ops == &shmem_aops; 74 } 75 #else 76 static inline bool shmem_mapping(struct address_space *mapping) 77 { 78 return false; 79 } 80 #endif /* CONFIG_SHMEM */ 81 extern void shmem_unlock_mapping(struct address_space *mapping); 82 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 83 pgoff_t index, gfp_t gfp_mask); 84 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 85 extern int shmem_unuse(unsigned int type, bool frontswap, 86 unsigned long *fs_pages_to_unuse); 87 88 extern bool shmem_huge_enabled(struct vm_area_struct *vma); 89 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 90 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 91 pgoff_t start, pgoff_t end); 92 93 /* Flag allocation requirements to shmem_getpage */ 94 enum sgp_type { 95 SGP_READ, /* don't exceed i_size, don't allocate page */ 96 SGP_CACHE, /* don't exceed i_size, may allocate page */ 97 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */ 98 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */ 99 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 100 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 101 }; 102 103 extern int shmem_getpage(struct inode *inode, pgoff_t index, 104 struct page **pagep, enum sgp_type sgp); 105 106 static inline struct page *shmem_read_mapping_page( 107 struct address_space *mapping, pgoff_t index) 108 { 109 return shmem_read_mapping_page_gfp(mapping, index, 110 mapping_gfp_mask(mapping)); 111 } 112 113 static inline bool shmem_file(struct file *file) 114 { 115 if (!IS_ENABLED(CONFIG_SHMEM)) 116 return false; 117 if (!file || !file->f_mapping) 118 return false; 119 return shmem_mapping(file->f_mapping); 120 } 121 122 extern bool shmem_charge(struct inode *inode, long pages); 123 extern void shmem_uncharge(struct inode *inode, long pages); 124 125 #ifdef CONFIG_USERFAULTFD 126 #ifdef CONFIG_SHMEM 127 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 128 struct vm_area_struct *dst_vma, 129 unsigned long dst_addr, 130 unsigned long src_addr, 131 bool zeropage, 132 struct page **pagep); 133 #else /* !CONFIG_SHMEM */ 134 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \ 135 src_addr, zeropage, pagep) ({ BUG(); 0; }) 136 #endif /* CONFIG_SHMEM */ 137 #endif /* CONFIG_USERFAULTFD */ 138 139 #endif 140