Linux kernel mirror (for testing)
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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
15struct 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
37struct 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
56static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
57{
58 return container_of(inode, struct shmem_inode_info, vfs_inode);
59}
60
61/*
62 * Functions in mm/shmem.c called directly from elsewhere:
63 */
64extern const struct fs_parameter_spec shmem_fs_parameters[];
65extern void shmem_init(void);
66extern int shmem_init_fs_context(struct fs_context *fc);
67extern struct file *shmem_file_setup(const char *name,
68 loff_t size, unsigned long flags);
69extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
70 unsigned long flags);
71extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
72 const char *name, loff_t size, unsigned long flags);
73extern int shmem_zero_setup(struct vm_area_struct *);
74extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
75 unsigned long len, unsigned long pgoff, unsigned long flags);
76extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
77#ifdef CONFIG_SHMEM
78extern const struct address_space_operations shmem_aops;
79static inline bool shmem_mapping(struct address_space *mapping)
80{
81 return mapping->a_ops == &shmem_aops;
82}
83#else
84static inline bool shmem_mapping(struct address_space *mapping)
85{
86 return false;
87}
88#endif /* CONFIG_SHMEM */
89extern void shmem_unlock_mapping(struct address_space *mapping);
90extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
91 pgoff_t index, gfp_t gfp_mask);
92extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
93int shmem_unuse(unsigned int type);
94
95extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
96 struct mm_struct *mm, unsigned long vm_flags);
97extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
98extern 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 */
102enum 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
110int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
111 enum sgp_type sgp);
112struct folio *shmem_read_folio_gfp(struct address_space *mapping,
113 pgoff_t index, gfp_t gfp);
114
115static 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
121static inline struct page *shmem_read_mapping_page(
122 struct address_space *mapping, pgoff_t index)
123{
124 return shmem_read_mapping_page_gfp(mapping, index,
125 mapping_gfp_mask(mapping));
126}
127
128static 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 */
144static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
145{
146 return max(eof, SHMEM_I(inode)->fallocend);
147}
148
149extern bool shmem_charge(struct inode *inode, long pages);
150extern void shmem_uncharge(struct inode *inode, long pages);
151
152#ifdef CONFIG_USERFAULTFD
153#ifdef CONFIG_SHMEM
154extern 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