Linux kernel mirror (for testing)
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linux
1#ifndef __SHMEM_FS_H
2#define __SHMEM_FS_H
3
4#include <linux/file.h>
5#include <linux/swap.h>
6#include <linux/mempolicy.h>
7#include <linux/pagemap.h>
8#include <linux/percpu_counter.h>
9#include <linux/xattr.h>
10
11/* inode in-kernel data */
12
13struct shmem_inode_info {
14 spinlock_t lock;
15 unsigned int seals; /* shmem seals */
16 unsigned long flags;
17 unsigned long alloced; /* data pages alloced to file */
18 unsigned long swapped; /* subtotal assigned to swap */
19 struct list_head shrinklist; /* shrinkable hpage inodes */
20 struct list_head swaplist; /* chain of maybes on swap */
21 struct shared_policy policy; /* NUMA memory alloc policy */
22 struct simple_xattrs xattrs; /* list of xattrs */
23 struct inode vfs_inode;
24};
25
26struct shmem_sb_info {
27 unsigned long max_blocks; /* How many blocks are allowed */
28 struct percpu_counter used_blocks; /* How many are allocated */
29 unsigned long max_inodes; /* How many inodes are allowed */
30 unsigned long free_inodes; /* How many are left for allocation */
31 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
32 umode_t mode; /* Mount mode for root directory */
33 unsigned char huge; /* Whether to try for hugepages */
34 kuid_t uid; /* Mount uid for root directory */
35 kgid_t gid; /* Mount gid for root directory */
36 struct mempolicy *mpol; /* default memory policy for mappings */
37 spinlock_t shrinklist_lock; /* Protects shrinklist */
38 struct list_head shrinklist; /* List of shinkable inodes */
39 unsigned long shrinklist_len; /* Length of shrinklist */
40};
41
42static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
43{
44 return container_of(inode, struct shmem_inode_info, vfs_inode);
45}
46
47/*
48 * Functions in mm/shmem.c called directly from elsewhere:
49 */
50extern int shmem_init(void);
51extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
52extern struct file *shmem_file_setup(const char *name,
53 loff_t size, unsigned long flags);
54extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
55 unsigned long flags);
56extern int shmem_zero_setup(struct vm_area_struct *);
57extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
58 unsigned long len, unsigned long pgoff, unsigned long flags);
59extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
60extern bool shmem_mapping(struct address_space *mapping);
61extern void shmem_unlock_mapping(struct address_space *mapping);
62extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
63 pgoff_t index, gfp_t gfp_mask);
64extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
65extern int shmem_unuse(swp_entry_t entry, struct page *page);
66
67extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
68extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
69 pgoff_t start, pgoff_t end);
70
71/* Flag allocation requirements to shmem_getpage */
72enum sgp_type {
73 SGP_READ, /* don't exceed i_size, don't allocate page */
74 SGP_CACHE, /* don't exceed i_size, may allocate page */
75 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
76 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
77 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
78 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
79};
80
81extern int shmem_getpage(struct inode *inode, pgoff_t index,
82 struct page **pagep, enum sgp_type sgp);
83
84static inline struct page *shmem_read_mapping_page(
85 struct address_space *mapping, pgoff_t index)
86{
87 return shmem_read_mapping_page_gfp(mapping, index,
88 mapping_gfp_mask(mapping));
89}
90
91static inline bool shmem_file(struct file *file)
92{
93 if (!IS_ENABLED(CONFIG_SHMEM))
94 return false;
95 if (!file || !file->f_mapping)
96 return false;
97 return shmem_mapping(file->f_mapping);
98}
99
100extern bool shmem_charge(struct inode *inode, long pages);
101extern void shmem_uncharge(struct inode *inode, long pages);
102
103#ifdef CONFIG_TMPFS
104
105extern int shmem_add_seals(struct file *file, unsigned int seals);
106extern int shmem_get_seals(struct file *file);
107extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
108
109#else
110
111static inline long shmem_fcntl(struct file *f, unsigned int c, unsigned long a)
112{
113 return -EINVAL;
114}
115
116#endif
117
118#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
119extern bool shmem_huge_enabled(struct vm_area_struct *vma);
120#else
121static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
122{
123 return false;
124}
125#endif
126
127#endif