Line data Source code
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 : unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */
29 : struct inode vfs_inode;
30 : };
31 :
32 : #define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE
33 : #define SHMEM_FL_USER_MODIFIABLE \
34 : (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
35 : #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL)
36 :
37 : struct shmem_sb_info {
38 : unsigned long max_blocks; /* How many blocks are allowed */
39 : struct percpu_counter used_blocks; /* How many are allocated */
40 : unsigned long max_inodes; /* How many inodes are allowed */
41 : unsigned long free_inodes; /* How many are left for allocation */
42 : raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
43 : umode_t mode; /* Mount mode for root directory */
44 : unsigned char huge; /* Whether to try for hugepages */
45 : kuid_t uid; /* Mount uid for root directory */
46 : kgid_t gid; /* Mount gid for root directory */
47 : bool full_inums; /* If i_ino should be uint or ino_t */
48 : ino_t next_ino; /* The next per-sb inode number to use */
49 : ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
50 : struct mempolicy *mpol; /* default memory policy for mappings */
51 : spinlock_t shrinklist_lock; /* Protects shrinklist */
52 : struct list_head shrinklist; /* List of shinkable inodes */
53 : unsigned long shrinklist_len; /* Length of shrinklist */
54 : };
55 :
56 : static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
57 : {
58 1 : return container_of(inode, struct shmem_inode_info, vfs_inode);
59 : }
60 :
61 : /*
62 : * Functions in mm/shmem.c called directly from elsewhere:
63 : */
64 : extern const struct fs_parameter_spec shmem_fs_parameters[];
65 : extern void shmem_init(void);
66 : extern int shmem_init_fs_context(struct fs_context *fc);
67 : extern struct file *shmem_file_setup(const char *name,
68 : loff_t size, unsigned long flags);
69 : extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
70 : unsigned long flags);
71 : extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
72 : const char *name, loff_t size, unsigned long flags);
73 : extern int shmem_zero_setup(struct vm_area_struct *);
74 : extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
75 : unsigned long len, unsigned long pgoff, unsigned long flags);
76 : extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
77 : #ifdef CONFIG_SHMEM
78 : extern const struct address_space_operations shmem_aops;
79 : static inline bool shmem_mapping(struct address_space *mapping)
80 : {
81 : return mapping->a_ops == &shmem_aops;
82 : }
83 : #else
84 : static inline bool shmem_mapping(struct address_space *mapping)
85 : {
86 : return false;
87 : }
88 : #endif /* CONFIG_SHMEM */
89 : extern void shmem_unlock_mapping(struct address_space *mapping);
90 : extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
91 : pgoff_t index, gfp_t gfp_mask);
92 : extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
93 : int shmem_unuse(unsigned int type);
94 :
95 : extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
96 : struct mm_struct *mm, unsigned long vm_flags);
97 : extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
98 : extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
99 : pgoff_t start, pgoff_t end);
100 :
101 : /* Flag allocation requirements to shmem_get_folio */
102 : enum sgp_type {
103 : SGP_READ, /* don't exceed i_size, don't allocate page */
104 : SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
105 : SGP_CACHE, /* don't exceed i_size, may allocate page */
106 : SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
107 : SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
108 : };
109 :
110 : int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
111 : enum sgp_type sgp);
112 : struct folio *shmem_read_folio_gfp(struct address_space *mapping,
113 : pgoff_t index, gfp_t gfp);
114 :
115 : static inline struct folio *shmem_read_folio(struct address_space *mapping,
116 : pgoff_t index)
117 : {
118 : return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping));
119 : }
120 :
121 : static inline struct page *shmem_read_mapping_page(
122 : struct address_space *mapping, pgoff_t index)
123 : {
124 0 : return shmem_read_mapping_page_gfp(mapping, index,
125 : mapping_gfp_mask(mapping));
126 : }
127 :
128 : static inline bool shmem_file(struct file *file)
129 : {
130 : if (!IS_ENABLED(CONFIG_SHMEM))
131 : return false;
132 : if (!file || !file->f_mapping)
133 : return false;
134 : return shmem_mapping(file->f_mapping);
135 : }
136 :
137 : /*
138 : * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
139 : * beyond i_size's notion of EOF, which fallocate has committed to reserving:
140 : * which split_huge_page() must therefore not delete. This use of a single
141 : * "fallocend" per inode errs on the side of not deleting a reservation when
142 : * in doubt: there are plenty of cases when it preserves unreserved pages.
143 : */
144 : static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
145 : {
146 : return max(eof, SHMEM_I(inode)->fallocend);
147 : }
148 :
149 : extern bool shmem_charge(struct inode *inode, long pages);
150 : extern void shmem_uncharge(struct inode *inode, long pages);
151 :
152 : #ifdef CONFIG_USERFAULTFD
153 : #ifdef CONFIG_SHMEM
154 : extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
155 : struct vm_area_struct *dst_vma,
156 : unsigned long dst_addr,
157 : unsigned long src_addr,
158 : bool zeropage, bool wp_copy,
159 : struct page **pagep);
160 : #else /* !CONFIG_SHMEM */
161 : #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \
162 : src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; })
163 : #endif /* CONFIG_SHMEM */
164 : #endif /* CONFIG_USERFAULTFD */
165 :
166 : #endif
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