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 : #include <linux/userfaultfd_k.h>
13 :
14 : /* inode in-kernel data */
15 :
16 : struct shmem_inode_info {
17 : spinlock_t lock;
18 : unsigned int seals; /* shmem seals */
19 : unsigned long flags;
20 : unsigned long alloced; /* data pages alloced to file */
21 : unsigned long swapped; /* subtotal assigned to swap */
22 : pgoff_t fallocend; /* highest fallocate endindex */
23 : struct list_head shrinklist; /* shrinkable hpage inodes */
24 : struct list_head swaplist; /* chain of maybes on swap */
25 : struct shared_policy policy; /* NUMA memory alloc policy */
26 : struct simple_xattrs xattrs; /* list of xattrs */
27 : atomic_t stop_eviction; /* hold when working on inode */
28 : struct timespec64 i_crtime; /* file creation time */
29 : unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */
30 : struct inode vfs_inode;
31 : };
32 :
33 : #define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE
34 : #define SHMEM_FL_USER_MODIFIABLE \
35 : (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
36 : #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL)
37 :
38 : struct shmem_sb_info {
39 : unsigned long max_blocks; /* How many blocks are allowed */
40 : struct percpu_counter used_blocks; /* How many are allocated */
41 : unsigned long max_inodes; /* How many inodes are allowed */
42 : unsigned long free_inodes; /* How many are left for allocation */
43 : raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
44 : umode_t mode; /* Mount mode for root directory */
45 : unsigned char huge; /* Whether to try for hugepages */
46 : kuid_t uid; /* Mount uid for root directory */
47 : kgid_t gid; /* Mount gid for root directory */
48 : bool full_inums; /* If i_ino should be uint or ino_t */
49 : bool noswap; /* ignores VM reclaim / swap requests */
50 : ino_t next_ino; /* The next per-sb inode number to use */
51 : ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
52 : struct mempolicy *mpol; /* default memory policy for mappings */
53 : spinlock_t shrinklist_lock; /* Protects shrinklist */
54 : struct list_head shrinklist; /* List of shinkable inodes */
55 : unsigned long shrinklist_len; /* Length of shrinklist */
56 : };
57 :
58 : static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
59 : {
60 1 : return container_of(inode, struct shmem_inode_info, vfs_inode);
61 : }
62 :
63 : /*
64 : * Functions in mm/shmem.c called directly from elsewhere:
65 : */
66 : extern const struct fs_parameter_spec shmem_fs_parameters[];
67 : extern void shmem_init(void);
68 : extern int shmem_init_fs_context(struct fs_context *fc);
69 : extern struct file *shmem_file_setup(const char *name,
70 : loff_t size, unsigned long flags);
71 : extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
72 : unsigned long flags);
73 : extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
74 : const char *name, loff_t size, unsigned long flags);
75 : extern int shmem_zero_setup(struct vm_area_struct *);
76 : extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
77 : unsigned long len, unsigned long pgoff, unsigned long flags);
78 : extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
79 : #ifdef CONFIG_SHMEM
80 : extern const struct address_space_operations shmem_aops;
81 : static inline bool shmem_mapping(struct address_space *mapping)
82 : {
83 : return mapping->a_ops == &shmem_aops;
84 : }
85 : #else
86 : static inline bool shmem_mapping(struct address_space *mapping)
87 : {
88 : return false;
89 : }
90 : #endif /* CONFIG_SHMEM */
91 : extern void shmem_unlock_mapping(struct address_space *mapping);
92 : extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
93 : pgoff_t index, gfp_t gfp_mask);
94 : extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
95 : int shmem_unuse(unsigned int type);
96 :
97 : extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
98 : struct mm_struct *mm, unsigned long vm_flags);
99 : #ifdef CONFIG_SHMEM
100 : extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
101 : #else
102 : static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
103 : {
104 : return 0;
105 : }
106 : #endif
107 : extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
108 : pgoff_t start, pgoff_t end);
109 :
110 : /* Flag allocation requirements to shmem_get_folio */
111 : enum sgp_type {
112 : SGP_READ, /* don't exceed i_size, don't allocate page */
113 : SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
114 : SGP_CACHE, /* don't exceed i_size, may allocate page */
115 : SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
116 : SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
117 : };
118 :
119 : int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
120 : enum sgp_type sgp);
121 : struct folio *shmem_read_folio_gfp(struct address_space *mapping,
122 : pgoff_t index, gfp_t gfp);
123 :
124 : static inline struct folio *shmem_read_folio(struct address_space *mapping,
125 : pgoff_t index)
126 : {
127 : return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping));
128 : }
129 :
130 : static inline struct page *shmem_read_mapping_page(
131 : struct address_space *mapping, pgoff_t index)
132 : {
133 : return shmem_read_mapping_page_gfp(mapping, index,
134 : mapping_gfp_mask(mapping));
135 : }
136 :
137 : static inline bool shmem_file(struct file *file)
138 : {
139 : if (!IS_ENABLED(CONFIG_SHMEM))
140 : return false;
141 : if (!file || !file->f_mapping)
142 : return false;
143 : return shmem_mapping(file->f_mapping);
144 : }
145 :
146 : /*
147 : * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
148 : * beyond i_size's notion of EOF, which fallocate has committed to reserving:
149 : * which split_huge_page() must therefore not delete. This use of a single
150 : * "fallocend" per inode errs on the side of not deleting a reservation when
151 : * in doubt: there are plenty of cases when it preserves unreserved pages.
152 : */
153 : static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
154 : {
155 : return max(eof, SHMEM_I(inode)->fallocend);
156 : }
157 :
158 : extern bool shmem_charge(struct inode *inode, long pages);
159 : extern void shmem_uncharge(struct inode *inode, long pages);
160 :
161 : #ifdef CONFIG_USERFAULTFD
162 : #ifdef CONFIG_SHMEM
163 : extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
164 : struct vm_area_struct *dst_vma,
165 : unsigned long dst_addr,
166 : unsigned long src_addr,
167 : uffd_flags_t flags,
168 : struct folio **foliop);
169 : #else /* !CONFIG_SHMEM */
170 : #define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
171 : src_addr, flags, foliop) ({ BUG(); 0; })
172 : #endif /* CONFIG_SHMEM */
173 : #endif /* CONFIG_USERFAULTFD */
174 :
175 : #endif
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