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