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