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