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
12/* inode in-kernel data */
13
14struct shmem_inode_info {
15 spinlock_t lock;
16 unsigned int seals; /* shmem seals */
17 unsigned long flags;
18 unsigned long alloced; /* data pages alloced to file */
19 unsigned long swapped; /* subtotal assigned to swap */
20 struct list_head shrinklist; /* shrinkable hpage inodes */
21 struct list_head swaplist; /* chain of maybes on swap */
22 struct shared_policy policy; /* NUMA memory alloc policy */
23 struct simple_xattrs xattrs; /* list of xattrs */
24 atomic_t stop_eviction; /* hold when working on inode */
25 struct inode vfs_inode;
26};
27
28struct shmem_sb_info {
29 unsigned long max_blocks; /* How many blocks are allowed */
30 struct percpu_counter used_blocks; /* How many are allocated */
31 unsigned long max_inodes; /* How many inodes are allowed */
32 unsigned long free_inodes; /* How many are left for allocation */
33 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
34 umode_t mode; /* Mount mode for root directory */
35 unsigned char huge; /* Whether to try for hugepages */
36 kuid_t uid; /* Mount uid for root directory */
37 kgid_t gid; /* Mount gid for root directory */
38 struct mempolicy *mpol; /* default memory policy for mappings */
39 spinlock_t shrinklist_lock; /* Protects shrinklist */
40 struct list_head shrinklist; /* List of shinkable inodes */
41 unsigned long shrinklist_len; /* Length of shrinklist */
42};
43
44static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
45{
46 return container_of(inode, struct shmem_inode_info, vfs_inode);
47}
48
49/*
50 * Functions in mm/shmem.c called directly from elsewhere:
51 */
52extern const struct fs_parameter_description shmem_fs_parameters;
53extern int shmem_init(void);
54extern int shmem_init_fs_context(struct fs_context *fc);
55extern struct file *shmem_file_setup(const char *name,
56 loff_t size, unsigned long flags);
57extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
58 unsigned long flags);
59extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
60 const char *name, loff_t size, unsigned long flags);
61extern int shmem_zero_setup(struct vm_area_struct *);
62extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
63 unsigned long len, unsigned long pgoff, unsigned long flags);
64extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
65#ifdef CONFIG_SHMEM
66extern bool shmem_mapping(struct address_space *mapping);
67#else
68static inline bool shmem_mapping(struct address_space *mapping)
69{
70 return false;
71}
72#endif /* CONFIG_SHMEM */
73extern void shmem_unlock_mapping(struct address_space *mapping);
74extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
75 pgoff_t index, gfp_t gfp_mask);
76extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
77extern int shmem_unuse(unsigned int type, bool frontswap,
78 unsigned long *fs_pages_to_unuse);
79
80extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
81extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
82 pgoff_t start, pgoff_t end);
83
84/* Flag allocation requirements to shmem_getpage */
85enum sgp_type {
86 SGP_READ, /* don't exceed i_size, don't allocate page */
87 SGP_CACHE, /* don't exceed i_size, may allocate page */
88 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
89 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
90 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
91 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
92};
93
94extern int shmem_getpage(struct inode *inode, pgoff_t index,
95 struct page **pagep, enum sgp_type sgp);
96
97static inline struct page *shmem_read_mapping_page(
98 struct address_space *mapping, pgoff_t index)
99{
100 return shmem_read_mapping_page_gfp(mapping, index,
101 mapping_gfp_mask(mapping));
102}
103
104static inline bool shmem_file(struct file *file)
105{
106 if (!IS_ENABLED(CONFIG_SHMEM))
107 return false;
108 if (!file || !file->f_mapping)
109 return false;
110 return shmem_mapping(file->f_mapping);
111}
112
113extern bool shmem_charge(struct inode *inode, long pages);
114extern void shmem_uncharge(struct inode *inode, long pages);
115
116#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
117extern bool shmem_huge_enabled(struct vm_area_struct *vma);
118#else
119static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
120{
121 return false;
122}
123#endif
124
125#ifdef CONFIG_SHMEM
126extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
127 struct vm_area_struct *dst_vma,
128 unsigned long dst_addr,
129 unsigned long src_addr,
130 struct page **pagep);
131extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
132 pmd_t *dst_pmd,
133 struct vm_area_struct *dst_vma,
134 unsigned long dst_addr);
135#else
136#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
137 src_addr, pagep) ({ BUG(); 0; })
138#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
139 dst_addr) ({ BUG(); 0; })
140#endif
141
142#endif