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 12 /* inode in-kernel data */ 13 14 struct shmem_inode_info { 15 spinlock_t lock; 16 unsigned int seals; /* shmem seals */ 17 unsigned long flags; 18 unsigned long alloced; /* data pages alloced to file */ 19 unsigned long swapped; /* subtotal assigned to swap */ 20 struct list_head shrinklist; /* shrinkable hpage inodes */ 21 struct list_head swaplist; /* chain of maybes on swap */ 22 struct shared_policy policy; /* NUMA memory alloc policy */ 23 struct simple_xattrs xattrs; /* list of xattrs */ 24 atomic_t stop_eviction; /* hold when working on inode */ 25 struct inode vfs_inode; 26 }; 27 28 struct shmem_sb_info { 29 unsigned long max_blocks; /* How many blocks are allowed */ 30 struct percpu_counter used_blocks; /* How many are allocated */ 31 unsigned long max_inodes; /* How many inodes are allowed */ 32 unsigned long free_inodes; /* How many are left for allocation */ 33 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 34 umode_t mode; /* Mount mode for root directory */ 35 unsigned char huge; /* Whether to try for hugepages */ 36 kuid_t uid; /* Mount uid for root directory */ 37 kgid_t gid; /* Mount gid for root directory */ 38 struct mempolicy *mpol; /* default memory policy for mappings */ 39 spinlock_t shrinklist_lock; /* Protects shrinklist */ 40 struct list_head shrinklist; /* List of shinkable inodes */ 41 unsigned long shrinklist_len; /* Length of shrinklist */ 42 }; 43 44 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 45 { 46 return container_of(inode, struct shmem_inode_info, vfs_inode); 47 } 48 49 /* 50 * Functions in mm/shmem.c called directly from elsewhere: 51 */ 52 extern const struct fs_parameter_description shmem_fs_parameters; 53 extern int shmem_init(void); 54 extern int shmem_init_fs_context(struct fs_context *fc); 55 extern struct file *shmem_file_setup(const char *name, 56 loff_t size, unsigned long flags); 57 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 58 unsigned long flags); 59 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 60 const char *name, loff_t size, unsigned long flags); 61 extern int shmem_zero_setup(struct vm_area_struct *); 62 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 63 unsigned long len, unsigned long pgoff, unsigned long flags); 64 extern int shmem_lock(struct file *file, int lock, struct user_struct *user); 65 #ifdef CONFIG_SHMEM 66 extern bool shmem_mapping(struct address_space *mapping); 67 #else 68 static inline bool shmem_mapping(struct address_space *mapping) 69 { 70 return false; 71 } 72 #endif /* CONFIG_SHMEM */ 73 extern void shmem_unlock_mapping(struct address_space *mapping); 74 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 75 pgoff_t index, gfp_t gfp_mask); 76 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); 77 extern int shmem_unuse(unsigned int type, bool frontswap, 78 unsigned long *fs_pages_to_unuse); 79 80 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 81 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 82 pgoff_t start, pgoff_t end); 83 84 /* Flag allocation requirements to shmem_getpage */ 85 enum sgp_type { 86 SGP_READ, /* don't exceed i_size, don't allocate page */ 87 SGP_CACHE, /* don't exceed i_size, may allocate page */ 88 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */ 89 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */ 90 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 91 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 92 }; 93 94 extern int shmem_getpage(struct inode *inode, pgoff_t index, 95 struct page **pagep, enum sgp_type sgp); 96 97 static inline struct page *shmem_read_mapping_page( 98 struct address_space *mapping, pgoff_t index) 99 { 100 return shmem_read_mapping_page_gfp(mapping, index, 101 mapping_gfp_mask(mapping)); 102 } 103 104 static inline bool shmem_file(struct file *file) 105 { 106 if (!IS_ENABLED(CONFIG_SHMEM)) 107 return false; 108 if (!file || !file->f_mapping) 109 return false; 110 return shmem_mapping(file->f_mapping); 111 } 112 113 extern bool shmem_charge(struct inode *inode, long pages); 114 extern void shmem_uncharge(struct inode *inode, long pages); 115 116 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE 117 extern bool shmem_huge_enabled(struct vm_area_struct *vma); 118 #else 119 static inline bool shmem_huge_enabled(struct vm_area_struct *vma) 120 { 121 return false; 122 } 123 #endif 124 125 #ifdef CONFIG_SHMEM 126 extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 127 struct vm_area_struct *dst_vma, 128 unsigned long dst_addr, 129 unsigned long src_addr, 130 struct page **pagep); 131 extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, 132 pmd_t *dst_pmd, 133 struct vm_area_struct *dst_vma, 134 unsigned long dst_addr); 135 #else 136 #define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \ 137 src_addr, pagep) ({ BUG(); 0; }) 138 #define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \ 139 dst_addr) ({ BUG(); 0; }) 140 #endif 141 142 #endif 143